check pt: Before going to Chi (11/07/23, random scripts, etc.)

It should always be a number between 1-65535

.gitignore

@@ -54,4 +54,6 @@ trace_data/
 /src/Spark.Admin.WebApp/src/bin/
 **/CMakeDeps.cmake
 **/CMakeDeps_win.cmake
-**/devcontainer.json
+**/.devcontainer
+*.Generated.cs
+*.lst

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "externals"]
 	path = externals
 	url = git@bitbucket.org:bluetradesys/externals.git
+[submodule "vcpkg"]
+	path = vcpkg
+	url = https://github.com/microsoft/vcpkg.git

CMakeLists.txt

@@ -151,7 +151,6 @@ else()
       FILES
       "${SPARK_LIB}/libACE-5.7.5.so"
       "${SPARK_LIB}/libOnixS.IceImpactMulticastPriceFeedHandlerCpp.so.3.16.0.0"
-      "${CMAKE_SOURCE_DIR}/externals/src/emumba/sparkd.lic"
       DESTINATION "${SPARK_INSTALL_PREFIX}/bin")
   endif()
 endif()

CMakePresets.json

@@ -26,6 +26,7 @@
         "CMAKE_CXX_STANDARD": "20",
         "CMAKE_SHARED_LINKER_FLAGS_DEBUG": "/DEBUG",
         "CMAKE_SHARED_LINKER_FLAGS_RELEASE": "/OPT:REF /OPT:ICF /LTCG",
+        "CMAKE_TOOLCHAIN_FILE": "${sourceDir}/vcpkg/scripts/buildsystems/vcpkg.cmake",
         "EXTERNALS_ROOT": "${sourceDir}/externals/windows",
         "CONFIG_DEFAULTS_PATH": "config/profiles/default/*.conf",
         "DOTNET_BINARY_DIR": "${sourceDir}/build/$<CONFIG>/bin/net7.0",
@@ -223,7 +224,10 @@
       "inherits": "spark",
       "displayName": "Data Stream Suite",
       "description": "Data Stream utils ported over from Edge",
-      "binaryDir": "${sourceDir}/build/${presetName}"
+      "binaryDir": "${sourceDir}/build/${presetName}",
+      "cacheVariables": {
+        "CONFIG_DEFAULTS_PATH": "config/profiles/default/*.conf;config/profiles/data_stream/*.conf"
+      }
     }
   ],
 

KeyCode.conf

@@ -0,0 +1,15 @@
+#nusers: 
+#allow concurrent : true
+#expires: 2024-Oct-06 00:00:00   638637696000000000
+#generation_time: 2023-Oct-06 18:58:48.015723   5250008173707545134
+EncryptedKeyCode {
+  value {
+    keycode: "KgoMeiVPzf/kv65GYGCyQQJVY/11sId6LYRwNNlNwA83+sISiSQnOZrziSgxjEAcaAZQn1nV4hY6MRi4XXznvxLYnDKf2bK0yktWWpSSqxqNxbDQ6AVSk5MGHptbsQSGYpYHlyCi0Niv8ES5NTj/FiBJXPrGEZABZBbNkqXIOa0HDdcxY+joeIf32ekX+5/LXN5XDTZBFT2A7q+IPDrFbKzSBvlzGOONSlq+XyKZZPqt0rXGO45V/GxFUTMYiEvn1/72iPGQ715tFXkr9ozGtitonnixzvW8Sfwmu7vM8VpWfoAc9D/1w5m5Ol5BS+Je8wigQysyrC8rud2KU+f7bQ=="
+  }
+}
+
+PublicKey {
+  value {
+    key: "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvvtV/IP1l/F85ME8N8H+\n8TCBOB68Lxd7sdR0geJGssLBq5F22IIlVKylNxiQV3TE6/hmL9dmr8FuUMrjPCal\nvma0axyAdyCMjFH3U0bYzzxnxSWuj5VJIgaZKOVQuX/3Hb+l4RZi7VWZgQFvEJ+F\ny66S2wDu4ey71Mt0yxkMsl5WMZBL3M1z+bt3pKzmBoyIMVLDcV1k1Yr2wspIRriZ\n95er3JWofK1P9s8B3OoqypEopLRW5hJaZN8YRpFNq5VwRUSj83KVobBAQTWDdOA5\nzOkixPVklZFaNyR06iT0gcgZUUM2bjyfQJGQ4GBCZpZb8KPPgtP+WhghoWby9OLv\nKQIDAQAB\n-----END PUBLIC KEY-----"
+  }
+}

cfgl

@@ -0,0 +1,33 @@
+diff.astextplain.textconv=astextplain
+filter.lfs.clean=git-lfs clean -- %f
+filter.lfs.smudge=git-lfs smudge -- %f
+filter.lfs.process=git-lfs filter-process
+filter.lfs.required=true
+http.sslbackend=openssl
+http.sslcainfo=C:/Program Files/Git/mingw64/etc/ssl/certs/ca-bundle.crt
+core.autocrlf=true
+core.fscache=true
+core.symlinks=false
+pull.rebase=false
+credential.helper=manager
+credential.https://dev.azure.com.usehttppath=true
+init.defaultbranch=master
+status.short=true
+core.repositoryformatversion=0
+core.filemode=false
+core.bare=false
+core.logallrefupdates=true
+core.symlinks=false
+core.ignorecase=true
+submodule.active=.
+remote.origin.url=git@bitbucket.org:bluetradesys/spark.git
+remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
+branch.spark_crypto.dev.remote=origin
+branch.spark_crypto.dev.merge=refs/heads/spark_crypto.dev
+submodule.docker/linux.url=git@bitbucket.org:bluetradesys/linux_docker.git
+submodule.docker/windows.url=git@bitbucket.org:bluetradesys/windows_docker.git
+submodule.externals.url=git@bitbucket.org:bluetradesys/externals.git
+branch.development.remote=origin
+branch.development.merge=refs/heads/development
+user.name=John Colvin
+user.email=john.colvin@bluetradesys.com

docker/sparkd/dev/Dockerfile

@@ -1,66 +1,104 @@
-FROM ubuntu:22.10
+FROM ubuntu:latest
 
-RUN \
-    apt-get update \
-    && DEBIAN_FRONTEND=noninteractive apt-get install -y \
+ARG DEBIAN_FRONTEND=noninteractive
+ENV TZ=America/New_York
+
+# light deps (should be quick to download/install)
+RUN apt-get update && apt-get install -y \
+    ca-certificates \
+    curl \
+    gnupg \
+    liblttng-ust-dev \
+    libpcap0.8-dev \
+    locales \
+    ninja-build \
+    software-properties-common \
+    sqlite3 \
+    tzdata
+
+# clang
+RUN apt-get update && apt-get install -y \
     clang-13 \
     clang-format-13 \
     clangd-13 \
     clang-15 \
     clang-format-15 \
-    clangd-15 \
-    cmake \
-    curl \
-    dotnet7 \
-    fish \
+    clangd-15
+
+# g++
+RUN apt-get update && apt-get install -y \
     g++-11 \
-    g++-12 \
-    gnupg \
-    liblttng-ust-dev \
-    libssh2-1-dev \
-    libpcap0.8-dev \
-    locales \
-    ninja-build \
-    nodejs \
-    npm \
-    openssh-server \
+    g++-12
+
+# python
+RUN apt-get update && apt-get install -y \
     python3-pip \
     python3-venv \
-    rapidjson-dev \
-    software-properties-common \
-    sqlite3 \
-    sudo \
-    tar \
-    vim \
-    wget
+    && python3 -m pip install --upgrade pip
 
-# this is done here so that ccache sees clang++ installed, not clang-10
-RUN \
-    apt-get update \
-    && DEBIAN_FRONTEND=noninteractive apt-get install -y ccache 
+# dotnet
+RUN apt-get update && apt-get install -y \
+    dotnet7
 
-# emumba deps
+# ssh
+RUN apt-get update && apt-get install -y \
+    libssh2-1-dev \
+    openssh-server
+
+# cmake
 RUN \
-    apt-get update \
-    && DEBIAN_FRONTEND=noninteractive apt-get install -y \
-    tzdata \
+    curl -fsSL https://apt.kitware.com/keys/kitware-archive-latest.asc 2> /dev/null \
+    | gpg --dearmor - \
+    | tee /usr/share/keyrings/kitware-archive-keyring.gpg > /dev/null \
+    && echo "deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ $(lsb_release -cs) main" \
+    | tee /etc/apt/sources.list.d/kitware.list > /dev/null \
+    && apt-get update \
+    && rm /usr/share/keyrings/kitware-archive-keyring.gpg \
+    && apt-get install -y kitware-archive-keyring \
+    && echo "deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ $(lsb_release -cs)-rc main" \
+    | tee -a /etc/apt/sources.list.d/kitware.list >/dev/null \
+    && apt-get install -y cmake
+
+# node
+ARG node_major=18
+RUN mkdir -p /etc/apt/keyrings \
+    && curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key \
+    | gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg \
+    && echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_$node_major.x nodistro main" \
+    | tee /etc/apt/sources.list.d/nodesource.list \
+    && apt-get update \
+    && apt-get install -y nodejs
+
+# ccache is done here so that ccache sees clang++ installed, not clang-10
+RUN apt-get update && apt-get install -y \
+    ccache 
+
+# emumba (light deps)
+RUN apt-get update && apt-get install -y \
     build-essential \
-    cmake-curses-gui \
-    git-all \
     doxygen \
     python3-sphinx \
     graphviz \
     libgtest-dev \
     libssl-dev \
+    rapidjson-dev \
+    zlib1g-dev \
+    pkg-config
+
+# emumba (boost)
+RUN apt-get update && apt-get install -y \
     libboost-filesystem-dev \
     libboost-program-options-dev \
     libboost-test-dev \
-    libboost-date-time-dev \
-    zlib1g-dev \
-    netcat-traditional \
-    net-tools \
-    gdb gdbserver \
-    pkg-config
+    libboost-date-time-dev
+
+# dev utils
+RUN apt-get update && apt-get install -y \ 
+    fish \
+    git-all \
+    sudo \
+    vim \
+    wget
 
 # set up default executables (update-alternatives)
 RUN \

docker/sparkd/dev/README.md

@@ -55,7 +55,7 @@ then select your container in the dropdown
 3. Push the new image to Docker Hub
 
    ```
-   docker push johncolvin/bluetradingsystems:sparkd-dev
+   docker push bluetradingsystems/sparkd-dev:latest
    ```
    ***Note:** The image doesn't have to be on Docker Hub, we can simply build
    it from scratch on our local machines (with the Dockerfile). However, this

docker/sparkd/dev/devcontainer.json

@@ -1,6 +1,7 @@
 {
   "image": "bluetradingsystems/sparkd-dev:latest",
-  "initializeCommand": "${localWorkspaceFolder}/docker/sparkd/dev/devcontainer_initialize.sh",
+  // Creates local dir to mount to HOME in docker 
+  "initializeCommand": "mkdir -p ${localEnv:HOME}/.bts/devcontainer-mounts/${devcontainerId}",
   "hostRequirements": {
     "memory": "4gb",
     "storage": "6gb"
@@ -27,6 +28,6 @@
     "8003:8003"
   ],
   "mounts": [
-    "source=${localEnv:HOME}/.sparkd-dev/mounts/sparkd-dev,target=/home/bts,type=bind"
+    "source=${localEnv:HOME}/.bts/devcontainer-mounts/${devcontainerId},target=/home/bts,type=bind"
   ]
 }

docker/sparkd/dev/devcontainer_initialize.sh

@@ -1,3 +0,0 @@
-#!/usr/bin/env bash
-
-mkdir -p "$HOME/.sparkd-dev/mounts/sparkd-dev"

get-token.py

@@ -0,0 +1,45 @@
+# import json
+# from rauth import OAuth2Service
+
+
+# class ExampleOAuth2Client:
+#     def __init__(self, url, path, client_id, client_secret):
+#         self.access_token = None
+#         self.service = OAuth2Service(
+#             name="foo",
+#             client_id=client_id,
+#             client_secret=client_secret,
+#             access_token_url=f'{url}{path}',
+#             authorize_url=f'{url}{path}',
+#             base_url=url,
+#         )
+#         self.get_access_token()
+
+#     def get_access_token(self):
+#         data = {
+#             'grant_type': 'client_credentials',  # generally required! 
+#         }
+#         session = self.service.get_auth_session(data=data, decoder=json.loads)
+#         self.access_token = session.access_token
+
+
+# def _main():
+#     client_id = 'API_THINKALPHA123'
+#     client_secret = '$MM9Rn*#qYARY$$QTMA#AMn*'
+#     oath = ExampleOAuth2Client(
+#         url='https://authnr.cmegroup.com',
+#         path='/as/token.oath2',
+#         client_id=client_id,
+#         client_secret=client_secret,
+#     )
+#     tok = oath.get_access_token()
+#     print(tok)
+
+
+# if __name__ == '__main__':
+#     try:
+#         _main()
+#     except json.JSONDecodeError as jde:
+#         print(f'get-token.py failed with json-decode-error: {jde}.\n{jde.doc}\n\nlineno: {jde.lineno}\npos: {jde.pos}')
+#     except Exception as e:
+#         print(f'get-token.py failed: {e}')

get-token2.py

@@ -0,0 +1,30 @@
+import subprocess
+
+
+def _main():
+    host = "markets.api.uat.cmegroup.com"
+    port = "443"
+    # AUTH_ENDPOINT="$host/marketdatastream/v1"
+    AUTH_ENDPOINT = 'https://authnr.cmegroup.com/as/token.oauth2'
+    API_KEY = "API_THINKALPHA123"
+    API_SECRET = '$MM9Rn*#qYARY$$QTMA#AMn*'
+
+    # Define your API key and secret
+    # API_KEY="YOUR_API_KEY"
+    # API_SECRET="YOUR_API_SECRET"
+
+    # Define the authentication API endpoint URL
+    # AUTH_ENDPOINT="https://api.example.com/auth"
+
+    # Perform the POST request and capture the response
+    # response=$(curl -s -X POST -d "api_key=$API_KEY&api_secret=$API_SECRET&grant_type=password&username=API_THINKALPHA123&password=$API_SECRET" "$AUTH_ENDPOINT")
+    # subprocess.run('ls')
+    subprocess.run(
+        f'curl -s -X POST -d "grant_type=client_credentials&client_id={API_KEY}&client_secret={API_SECRET}" "{AUTH_ENDPOINT}"',
+    )
+
+
+# curl --user 'API_THINKALPHA123:$MM9Rn*#qYARY$$QTMA#AMn*' 'https://query-api.datamine.cmegroup.com/v3/query/query_order_record?tradedate=2023-07-10&fields=symbol,transacttime,instrumentsequencenumber,tradeprice,tradequantity,tradeflag&q=asset.eq.TN,securitytype.eq.FUT,tradeflag.nin.OBS&fileFormat=csv&securityexchange=XCBT&underlyingproduct=Interest%20Rate'
+
+if __name__ == '__main__':
+    _main()

good-dev-readme.md

@@ -0,0 +1,211 @@
+[cmake]: https://cmake.org/
+[cmake ext]: https://marketplace.visualstudio.com/items?itemName=ms-vscode.cmake-tools
+[cmake presets]: https://cmake.org/cmake/help/latest/manual/cmake-presets.7.html
+[clangd ext]: https://marketplace.visualstudio.com/items?itemName=llvm-vs-code-extensions.vscode-clangd
+[cpp ext]: https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools
+[docker]: https://www.docker.com/
+[dotnet]: https://dotnet.microsoft.com/en-us/download/dotnet
+[ninja build]: https://ninja-build.org/
+[ninja generator]: https://cmake.org/cmake/help/latest/generator/Ninja.html
+[ninja multi-config generator]: https://cmake.org/cmake/help/latest/generator/Ninja%20Multi-Config.html
+[python]: https://www.python.org/
+[py venv]: https://docs.python.org/3/library/venv.html
+[visual studio]: https://visualstudio.microsoft.com/
+[visual studio generator]: https://cmake.org/cmake/help/latest/generator/Visual%20Studio%2017%202022.html
+[devcontainer]: https://code.visualstudio.com/docs/devcontainers/create-dev-container
+
+# C++ Intellisense for Spark on Windows (VS Code)
+**Steps**
+1. Install the **[C++ extension][cpp ext]**
+2. Install the **[CMake extension][cmake ext]**
+3. Copy `c_cpp_properties.json` from this folder to `$workspaceFolder/.vscode/`
+4. In the VS Code Command Palette, run `CMake: Select Configure Preset`, then
+   select '**spark**' from the dropdown
+
+**Notes**
+* Intellisense won't work for generated files/types until you build libspark
+
+# C++ Intellisense for Sparkd on Linux (VS Code)
+1. Install the **[CMake extension][cmake ext]**
+2. Install the **[Clangd extension][clangd ext]**
+3. (Optional) Install the **[C++ extension][cpp ext]** (*needed for debugging,
+   but intellisense should work without it*).
+4. If the **[C++ extension][cpp ext]** is installed, disable its intellisense in
+  your workspace settings (*Clangd intellisense is better*)
+   ```
+   "C_Cpp.intelliSenseEngine": "disabled"
+   ```
+5. In the VS Code Command Palette, run **CMake: Select Configure Preset**, then select the
+  **[preset][cmake presets]** you wish to build from the dropdown
+   * *The **Clang** presets may work best with the **Clangd** extension*
+   * *Intellisense won't work for generated files/types until you build libspark*
+
+# Build Spark on Windows
+### **Dependencies**
+* **[CMake][cmake]** (version >= 3.23)
+* **[Python][python]** (version >= 3.9)
+* **[Visual Studio][visual studio]** (2022)
+* **[Dotnet][dotnet]** (sdk version >= 7.0.0)
+
+### **References**
+* **[CMakePresets][cmake presets]**
+* **[Visual Studio 17 2022 (CMake generator)][visual studio generator]**
+* **[Python Virtual Environment][py venv]**
+> *Run commands from the repo root dir unless otherwise noted*
+1. Set up the **[Python virtual environment][py venv]**<br>
+   ```
+   # Create the virtual environment
+   python3 -m venv .venv
+
+   # Activate the virtual environment
+   .venv\bin\activate.bat
+
+   # Update pip
+   python -m pip install --upgrade pip
+
+   # Install packages
+   pip install -r requirements.txt
+   ```
+2. Build
+   > *Run commands in python virtual environment*
+   ```
+
+   # Configure
+   cmake --preset spark
+
+   # Build Debug
+   cmake --build --preset spark-debug
+   dotnet build spark_client.sln --configuration Debug
+
+   # Build Release
+   cmake --build --preset spark-release
+   dotnet build spark_client.sln --configuration Release
+   ```
+
+# Build Sparkd on Linux
+### **Dependencies**
+* **[CMake][cmake]** (version >= 3.23)
+* **[Ninja Build][ninja build]**
+* **[Python][python]** (version >= 3.9)
+* **[Docker][docker]**
+
+### **References**
+* **[CMakePresets][cmake presets]**
+* **[Ninja (CMake generator)][ninja generator]**
+* **[Python Virtual Environment][py venv]**
+* **[Devcontainer](devcontainer)**
+
+### **Prerequisites**
+* Open repository in a VS Code [Devcontainer](../docker/sparkd/dev/README.md), or
+  create your own [docker container](../docker/sparkd/dev/README.md) in which to build
+> *Run commands from the repo root dir unless otherwise noted*<br>
+1. Set up the **[Python virtual environment][py venv]**
+   ```
+   # Create the virtual environment
+   python3 -m venv .venv
+
+   # Activate the virtual environment
+   . .venv/bin/activate
+
+   # Update pip
+   python -m pip install --upgrade pip
+
+   # Install packages
+   pip install -r requirements.txt
+   ```
+2. Build
+   > *Run commands in python virtual environment*
+   ```
+   # Configure clang debug
+   cmake --preset sparkd-clang-debug
+
+   # Build clang debug
+   cmake --build --preset spark-clang-debug
+
+   # Configure gcc release
+   cmake --build --preset sparkd-gcc-release
+   
+   # Build gcc release
+   cmake --build --preset sparkd-gcc-release
+   ```
+
+# Build Spark Api Server on Windows
+### **Dependencies**
+* **[CMake][cmake]** (version >= 3.23)
+* **[Python][python]** (version >= 3.9)
+* **[Visual Studio][visual studio]** (version)
+* **[Dotnet][dotnet]** (sdk version >= 7.0.0)
+
+### **References**
+* **[CMakePresets][cmake presets]**
+* **[Visual Studio 17 2022 (CMake generator)][visual studio generator]**
+* **[Python Virtual Environment][py venv]**
+> *Run commands from the repo root dir unless otherwise noted*
+1. Set up the **[Python Virtual Environment][py venv]**
+   ```
+   # Create the virtual environment
+   python3 -m venv .venv
+
+   # Activate the virtual environment
+   .venv\bin\activate.bat
+
+   # Update pip
+   python -m pip install --upgrade pip
+
+   # Install packages
+   pip install -r requirements.txt
+   ```
+2. Build
+   > *Run in python virtual environment*
+   ```
+   # Configure
+   cmake --preset spark-api-server-windows
+
+   # Build debug
+   cmake --build --preset spark-api-server-windows-debug
+   dotnet build Spark.Api.Server.sln --configuration Debug
+
+   # Build release
+   cmake --build --preset spark-api-server-windows-release
+   dotnet build Spark.Api.Server.sln --configuration Release
+   ```
+
+## Linux
+### **Dependencies**
+* **[CMake][cmake]** (version >= 3.23)
+* **[Python][python]** (version >= 3.9)
+* **[Dotnet][dotnet]** (sdk version >= 7.0.0)
+
+### **References**
+* **[CMakePresets][cmake presets]**
+* **[Ninja Multi-Config (CMake generator)][ninja multi-config generator]**
+* **[Python Virtual Environment][py venv]**
+> *Run commands from the repo root dir unless otherwise noted*
+1. Set up the **[Python Virtual Environment][py venv]**
+   ```
+   # Create the virtual environment
+   python3 -m venv .venv
+
+   # Activate the virtual environment
+   . .venv/bin/activate
+
+   # Update pip
+   python -m pip install --upgrade pip
+
+   # Install packages
+   pip install -r requirements.txt
+   ```
+2. Build
+   > *Run in python virtual environment*
+   ```
+   # Configure
+   cmake --preset spark-api-server-linux
+
+   # Build debug
+   cmake --build --preset spark-api-server-linux-debug
+   dotnet build Spark.Api.Server.sln --configuration Debug
+
+   # Build release
+   cmake --build --preset spark-api-server-linux-release
+   dotnet build Spark.Api.Server.sln --configuration Release
+   ```

mdstream_diff.patch

@@ -0,0 +1,66 @@
+diff --git a/src/DataStreamSuite/SharedStreams/Business/MarketData/MDStream.cs b/src/DataStreamSuite/SharedStreams/Business/MarketData/MDStream.cs
+index 643146112..e334c3aba 100644
+--- a/src/DataStreamSuite/SharedStreams/Business/MarketData/MDStream.cs
++++ b/src/DataStreamSuite/SharedStreams/Business/MarketData/MDStream.cs
+@@ -1,7 +1,9 @@
+ namespace BCG {
+    using BCG.Utilities.General;
+ 
++   using bts;
+    using bts.api;
++   using bts.api.core;
+    using bts.api.domain;
+    using bts.api.synthetic;
+    using bts.md;
+@@ -14,6 +16,7 @@ namespace BCG {
+    using mbts.spark;
+    using mbts.ui;
+ 
++   using Spark.Api.MarketData;
+    using Spark.Core.Data;
+    using Spark.Core.Disposables;
+    using Spark.Core.Reactive;
+@@ -39,6 +42,8 @@ namespace BCG {
+          new ColumnInfo("sec", 1, typeof(string))}, "md");
+ 
+       private BlueTable _rows;
++      readonly MarketDataClient mdClient;
++      IDisposable? mdSub;
+ 
+       public MDStream()
+       : this(String.Empty, ViewStreamDatabase.instance) {
+@@ -49,14 +54,27 @@ namespace BCG {
+          _symbol = symbol;
+          _rows = new BlueTable(_schema);
+          _md_source = new MDSource(TimeSpan.FromSeconds(0.5));
++         mdClient = new(_md_source);
+       }
+ 
+       protected override void myOnFirstSubscriber() {
+          _vsd.addWorker(this);
+          _md_source.subscribe_securities().Subscribe(c => on_md(c));
++         Log.isnull(mdSub);
++         mdSub = mdClient.books().Subscribe(onBooks);
+          //base.myOnFirstSubscriber();
+       }
+ 
++      void onBooks(TableUpdate<BookTuple, uint> update) {
++         foreach (var book in update.added) {
++            bts.Log.Gen.info($"MDStream.on_md sec: {book.security}");
++            var sec = book.security;
++            IBlueRow r = new BlueRow(_schema, _id++, sec.ToString());
++            _rows.addRow(r);
++            _is_dirty = true;
++         }
++      }
++
+       protected override void myOnLastSubscriber() {
+          //base.myOnLastSubscriber();
+          _vsd.removeWorker(this);
+@@ -82,4 +100,4 @@ namespace BCG {
+          }
+       }
+    }
+-}
+\ No newline at end of file
++}

patches-ohoolihan

@@ -0,0 +1,112 @@
+diff --git a/src/client/spark/AW2/VolSurfaceExtensions.cs b/src/client/spark/AW2/VolSurfaceExtensions.cs
+index 6279d82a2..c143902a7 100644
+--- a/src/client/spark/AW2/VolSurfaceExtensions.cs
++++ b/src/client/spark/AW2/VolSurfaceExtensions.cs
+@@ -162,7 +162,8 @@ namespace mbts.spark {
+             api_sec_exp.Exchange.to_venue(),
+             api_sec_exp.SecurityType.contract_case(),
+             api_sec_exp.Symbol,
+-            api_sec_exp.Expiration.date_time());
++            api_sec_exp.HasExpiration ?
++               api_sec_exp.Expiration.date_time() : SecurityExpiration.empty.expiration);
+ 
+       public static SecurityExpiration to_sec_exp(this Security sec) =>
+          to_sec_exp(new SecurityImmutable(sec));
+diff --git a/src/client/spark/Analytics/Core/Settings/SecurityExpiration.cs b/src/client/spark/Analytics/Core/Settings/SecurityExpiration.cs
+index bf9f44455..b2ac80561 100644
+--- a/src/client/spark/Analytics/Core/Settings/SecurityExpiration.cs
++++ b/src/client/spark/Analytics/Core/Settings/SecurityExpiration.cs
+@@ -3,6 +3,7 @@ namespace mbts {
+    using bts.api;
+    using bts.utils;
+ 
++   using mbts.spark;
+    using mbts.ui.utility;
+    using mbts.utils;
+ 
+@@ -25,6 +26,9 @@ namespace mbts {
+          SecurityTuple.empty.security_name,
+          DateTime.MinValue);
+ 
++      public static bts.api.domain.SecurityExpirationImmutable empty_api_sec_expi =>
++         empty.to_api_sec_expi();
++
+       // for deserialization
+       SecurityExpiration() =>
+          security_tuple = SecurityTuple.empty;
+diff --git a/src/client/spark/Analytics/SupportingData/AnalyticsExpirationParameters.cs b/src/client/spark/Analytics/SupportingData/AnalyticsExpirationParameters.cs
+index f5e2a73d6..0ea7b34be 100644
+--- a/src/client/spark/Analytics/SupportingData/AnalyticsExpirationParameters.cs
++++ b/src/client/spark/Analytics/SupportingData/AnalyticsExpirationParameters.cs
+@@ -50,9 +50,7 @@ namespace mbts.analytics {
+          deliverable_security ??= SecurityExpiration.empty;
+          roll_schedule_expiration ??= SecurityExpiration.empty;
+ 
+-         this.driver = driver ?? new(new() {
+-            TimeWeightedInterpolated = new()
+-         });
++         this.driver = driver ?? _default_driver;
+          _deliverable = deliverable_security.to_api_sec_expi();
+          _roll_schedule = roll_schedule_expiration.to_api_sec_expi();
+          this.roll_target = roll_target;
+@@ -63,10 +61,10 @@ namespace mbts.analytics {
+       }
+ 
+       public AnalyticsExpirationParameters(ExpirationParameterEntryImmutable db_i) {
+-         _security = db_i.SecurityExpiration;
+-         _deliverable = db_i.Deliverable;
+-         _roll_schedule = db_i.RollSchedule;
+-         driver = db_i.Driver;
++         _security = db_i.HasSecurityExpiration ? db_i.SecurityExpiration : _default_api_sec_expi;
++         _deliverable = db_i.HasDeliverable ? db_i.Deliverable : _default_api_sec_expi;
++         _roll_schedule = db_i.HasRollSchedule ? db_i.RollSchedule : _default_api_sec_expi;
++         driver = db_i.HasDriver ? db_i.Driver : _default_driver;
+          roll_target = db_i.RollTarget;
+          riskless_rate = db_i.RisklessRate;
+          settlement_price = db_i.SettlementPrice;
+@@ -74,6 +72,12 @@ namespace mbts.analytics {
+          vega_beta = db_i.VegaBeta;
+       }
+ 
++      static ExpirationDriverImmutable _default_driver =>
++         new(new() { TimeWeightedInterpolated = new() });
++
++      static bts.api.domain.SecurityExpirationImmutable _default_api_sec_expi =>
++         SecurityExpiration.empty_api_sec_expi;
++
+       public SecurityExpiration security => _security.to_sec_exp();
+       public SecurityExpiration driver_security => driver.HasSecurity ?
+          driver.Security.to_sec_exp() : SecurityExpiration.empty;
+diff --git a/src/client/spark/NMSheets/DataProviders/NMSheetSingleOptionMainDataSource.cs b/src/client/spark/NMSheets/DataProviders/NMSheetSingleOptionMainDataSource.cs
+index 622121388..ec902f142 100644
+--- a/src/client/spark/NMSheets/DataProviders/NMSheetSingleOptionMainDataSource.cs
++++ b/src/client/spark/NMSheets/DataProviders/NMSheetSingleOptionMainDataSource.cs
+@@ -233,9 +233,18 @@ namespace BCG {
+       private IDictionary<DateTime, ATMData> _get_atm_data(ExpStrikeKeyedData<mbts.spark.TheoPoint> theo_data) {
+          NMSheetSettings sheet_settings = _threaded_bb.read_state(_in_bb_sheet_settings_tag) ?? new NMSheetSettings();
+          VolSurfaceNonVolInput vs_nvinp = _threaded_bb.read_state(_in_exp_param_tag);
+-         IDictionary<DateTime, double> option_exp_roll_data = vs_nvinp != null ?
+-            vs_nvinp.get_roll_map((exp) => exp.symbol == _nmsheet_symbol.option_name && exp.security_type == SecurityType.Option).ToDictionary(kv => kv.Key.expiration, kv => kv.Value) :
+-            new Dictionary<DateTime, double>();
++         var option_sym_exp_groups = vs_nvinp
++            ?.get_roll_map(exp =>
++               exp.symbol == _nmsheet_symbol.option_name &&
++               exp.security_type == SecurityType.Option)
++            ?.GroupBy(kv => kv.Key.expiration)
++            ?.ToDictionary(kv => kv.Key, kv => kv.ToList());
++         var option_exp_roll_data = vs_nvinp
++            ?.get_roll_map(exp =>
++               exp.symbol == _nmsheet_symbol.option_name &&
++               exp.security_type == SecurityType.Option)
++            ?.ToDictionary(kv => kv.Key.expiration, kv => kv.Value)
++            ?? new();
+          IDictionary<DateTime, ATMData> atm_data = OptionATMDataSource.compute_atm_data(_nmsheet_symbol.option_name, _get_onefive(), theo_data, option_exp_roll_data);
+          if (sheet_settings.setting_atm.select_atm_nearest_strike_only)
+             foreach (ATMData exp_atm_data in atm_data.Values)
+@@ -306,4 +315,4 @@ namespace BCG {
+       }
+       #endregion
+    }
+-}
+\ No newline at end of file
++}

playground-1.mongodb.js

@@ -0,0 +1,45 @@
+/* global use, db */
+// MongoDB Playground
+// To disable this template go to Settings | MongoDB | Use Default Template For Playground.
+// Make sure you are connected to enable completions and to be able to run a playground.
+// Use Ctrl+Space inside a snippet or a string literal to trigger completions.
+// The result of the last command run in a playground is shown on the results panel.
+// By default the first 20 documents will be returned with a cursor.
+// Use 'console.log()' to print to the debug output.
+// For more documentation on playgrounds please refer to
+// https://www.mongodb.com/docs/mongodb-vscode/playgrounds/
+
+// Select the database to use.
+use('mongodbVSCodePlaygroundDB');
+
+// Insert a few documents into the sales collection.
+db.getCollection('sales').insertMany([
+    { 'item': 'abc', 'price': 10, 'quantity': 2, 'date': new Date('2014-03-01T08:00:00Z') },
+    { 'item': 'jkl', 'price': 20, 'quantity': 1, 'date': new Date('2014-03-01T09:00:00Z') },
+    { 'item': 'xyz', 'price': 5, 'quantity': 10, 'date': new Date('2014-03-15T09:00:00Z') },
+    { 'item': 'xyz', 'price': 5, 'quantity': 20, 'date': new Date('2014-04-04T11:21:39.736Z') },
+    { 'item': 'abc', 'price': 10, 'quantity': 10, 'date': new Date('2014-04-04T21:23:13.331Z') },
+    { 'item': 'def', 'price': 7.5, 'quantity': 5, 'date': new Date('2015-06-04T05:08:13Z') },
+    { 'item': 'def', 'price': 7.5, 'quantity': 10, 'date': new Date('2015-09-10T08:43:00Z') },
+    { 'item': 'abc', 'price': 10, 'quantity': 5, 'date': new Date('2016-02-06T20:20:13Z') },
+]);
+
+// Run a find command to view items sold on April 4th, 2014.
+const salesOnApril4th = db.getCollection('sales').find({
+    date: { $gte: new Date('2014-04-04'), $lt: new Date('2014-04-05') }
+}).count();
+
+// Print a message to the output window.
+console.log(`${salesOnApril4th} sales occurred in 2014.`);
+
+// Here we run an aggregation and open a cursor to the results.
+// Use '.toArray()' to exhaust the cursor to return the whole result set.
+// You can use '.hasNext()/.next()' to iterate through the cursor page by page.
+db.getCollection('sales').aggregate([
+    // Find all of the sales that occurred in 2014.
+    { $match: { date: { $gte: new Date('2014-01-01'), $lt: new Date('2015-01-01') } } },
+    // Group the total sales for each product.
+    { $group: { _id: '$item', totalSaleAmount: { $sum: { $multiply: ['$price', '$quantity'] } } } }
+]);
+
+

simon_private.pem

@@ -0,0 +1,30 @@
+-----BEGIN ENCRYPTED PRIVATE KEY-----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+-----END ENCRYPTED PRIVATE KEY-----

simon_public.pem

@@ -0,0 +1,9 @@
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvvtV/IP1l/F85ME8N8H+
+8TCBOB68Lxd7sdR0geJGssLBq5F22IIlVKylNxiQV3TE6/hmL9dmr8FuUMrjPCal
+vma0axyAdyCMjFH3U0bYzzxnxSWuj5VJIgaZKOVQuX/3Hb+l4RZi7VWZgQFvEJ+F
+y66S2wDu4ey71Mt0yxkMsl5WMZBL3M1z+bt3pKzmBoyIMVLDcV1k1Yr2wspIRriZ
+95er3JWofK1P9s8B3OoqypEopLRW5hJaZN8YRpFNq5VwRUSj83KVobBAQTWDdOA5
+zOkixPVklZFaNyR06iT0gcgZUUM2bjyfQJGQ4GBCZpZb8KPPgtP+WhghoWby9OLv
+KQIDAQAB
+-----END PUBLIC KEY-----

src/DataStreamSuite/ArithmeticExpressions/AdditiveInverse.cs

@@ -0,0 +1,37 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Numerics;
+
+class AdditiveInverse : IArithmeticExpression<double> {
+   readonly IArithmeticExpression expression;
+
+   public AdditiveInverse(IArithmeticExpression expression) =>
+      this.expression = expression;
+
+   public static AdditiveInverse<T> Create<T>(IArithmeticExpression<T> expression)
+      where T : INumber<T> =>
+      new(expression);
+
+   public double Evaluate(IDictionary<string, object?> env) =>
+      -evaluateArg(expression, nameof(expression), env);
+
+   static double evaluateArg(
+      IArithmeticExpression expr, string name, IDictionary<string, object?> env) {
+      var obj = expr.Evaluate(env);
+      return ConvertUtils.try_convert(expr.Evaluate(env), out double dbl) ? dbl :
+         throw new Exception(
+            $"Invalid AdditiveInverse. {name} is of type {obj?.GetType()} " +
+            $"(expected {typeof(double)})");
+   }
+}
+
+class AdditiveInverse<T> : IArithmeticExpression<T>
+   where T : INumber<T> {
+   readonly IArithmeticExpression<T> expression;
+
+   public AdditiveInverse(IArithmeticExpression<T> expression) =>
+      this.expression = expression;
+
+   public T Evaluate(IDictionary<string, object?> env) =>
+      -expression.Evaluate(env);
+}

src/DataStreamSuite/ArithmeticExpressions/ArithmeticExpressionExtensions.cs

@@ -0,0 +1,45 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Numerics;
+
+public static class ArithmeticExpressionExtensions {
+   public static IArithmeticExpression<TResult> Add<TLeft, TRight, TResult>(
+      this IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right)
+      where TLeft :
+         INumber<TLeft>,
+         IAdditionOperators<TLeft, TRight, TResult>
+      where TRight : INumber<TRight>
+      where TResult : INumber<TResult> =>
+      new Sum<TLeft, TRight, TResult>(left, right);
+
+   public static IArithmeticExpression<TResult> Subtract<TLeft, TRight, TResult>(
+      this IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right)
+      where TLeft :
+         INumber<TLeft>,
+         ISubtractionOperators<TLeft, TRight, TResult>
+      where TRight : INumber<TRight>
+      where TResult : INumber<TResult> =>
+      new Difference<TLeft, TRight, TResult>(left, right);
+
+   public static IArithmeticExpression<TResult> Multiply<TLeft, TRight, TResult>(
+      this IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right)
+      where TLeft :
+         INumber<TLeft>,
+         IMultiplyOperators<TLeft, TRight, TResult>
+      where TRight : INumber<TRight>
+      where TResult : INumber<TResult> =>
+      new Product<TLeft, TRight, TResult>(left, right);
+
+   public static IArithmeticExpression<TResult> Divide<TLeft, TRight, TResult>(
+      this IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right)
+      where TLeft :
+         INumber<TLeft>,
+         IDivisionOperators<TLeft, TRight, TResult>
+      where TRight : INumber<TRight>
+      where TResult : INumber<TResult> =>
+      new Quotient<TLeft, TRight, TResult>(left, right);
+
+   public static IArithmeticExpression<T> Negate<T>(this IArithmeticExpression<T> expression)
+      where T : INumber<T> =>
+      new AdditiveInverse<T>(expression);
+}

src/DataStreamSuite/ArithmeticExpressions/ArithmeticExpressionGrammar.y

@@ -0,0 +1,99 @@
+%namespace Bts.ArithmeticExpressions
+%partial
+%visibility internal
+%tokentype Token
+%parsertype ArithmeticExpressionParserImpl
+
+%union {
+   public int Integer;
+   public double Real;
+   public string Identifier;
+   public DateTime DateTime; 
+   public ImmutableList<IArithmeticExpression> Arguments;
+   public ImmutableList<Assignment> Assignments;
+   public IArithmeticExpression Argument;
+   public Assignment Assignment;
+   public ArithmeticProgram Program;
+}
+
+/* Constants  */
+%token INTEGER_CONSTANT REAL_CONSTANT
+/* Arithmetic Operators */
+%token ADD, SUBTRACT, MULTIPLY, DIVIDE, EQUALS
+/* Syntax */
+%token PARENTHESIS_OPEN, PARENTHESIS_CLOSE, COMMA, IDENTIFIER
+
+%left ADD SUBTRACT
+%left MULTIPLY DIVIDE
+%nonassoc EQUALS
+
+%type <Argument> Argument
+%type <Arguments> Arguments
+%type <Assignment> Assignment
+%type <Assignments> Assignments
+%type <Program> Program
+
+%%
+
+Program :
+   Assignments {
+      $$ = new($1);
+   }
+   ;
+
+Assignments :
+   Assignment {
+      $$ = ImmutableList<Assignment>.Empty.Add($1);
+   }
+   | Assignments Assignment {
+      $$ = $1.Add($2);
+   }
+   ;
+
+Assignment :
+   IDENTIFIER EQUALS Argument {
+      $$ = new($1.Identifier, $3);
+   }
+   ;
+
+Argument :
+   IDENTIFIER PARENTHESIS_OPEN Arguments PARENTHESIS_CLOSE {
+      $$ = new Function($1.Identifier, $3);
+   }
+   | INTEGER_CONSTANT {
+      $$ = new IntegerConstant($1.Integer);
+   }
+   | REAL_CONSTANT {
+      $$ = new RealConstant($1.Real);
+   }
+   | IDENTIFIER {
+      $$ = new Variable($1.Identifier);
+   }
+   | SUBTRACT Argument {
+      $$ = $2.Negate();
+   }
+   | PARENTHESIS_OPEN Argument PARENTHESIS_CLOSE {
+      $$ = $2;
+   }
+   | Argument MULTIPLY Argument {
+      $$ = $1.Multiply($3);
+   }
+   | Argument DIVIDE Argument {
+      $$ = $1.Divide($3);
+   }
+   | Argument ADD Argument {
+      $$ = $1.Add($3);
+   }
+   | Argument SUBTRACT Argument {
+      $$ = $1.Subtract($3);
+   }
+   ;
+
+Arguments :
+   Argument {
+      $$ = ImmutableList<IArithmeticExpression>.Empty.Add($1);
+   }
+   | Arguments COMMA Argument {
+      $$ = $1.Add($3);
+   }
+   ;

src/DataStreamSuite/ArithmeticExpressions/ArithmeticExpressionParserImpl.cs

@@ -0,0 +1,19 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Text;
+
+partial class ArithmeticExpressionParserImpl {
+   public ArithmeticExpressionParserImpl() : base(null) { }
+
+   public ValueType Parse(Stream stream) {
+      Scanner = new ArithmeticExpressionScanner(stream);
+      Parse();
+      return CurrentSemanticValue;
+   }
+
+   public ValueType Parse(string str) {
+      var inputBuffer = Encoding.Default.GetBytes(str);
+      using var stream = new MemoryStream(inputBuffer);
+      return Parse(stream);
+   }
+}

src/DataStreamSuite/ArithmeticExpressions/ArithmeticExpressionScanner.cs

@@ -0,0 +1,11 @@
+namespace Bts.ArithmeticExpressions;
+
+using System;
+
+partial class ArithmeticExpressionScanner {
+   public override void yyerror(string format, params object[] args) {
+      base.yyerror(format, args);
+      Console.WriteLine(format, args);
+      Console.WriteLine();
+   }
+}

src/DataStreamSuite/ArithmeticExpressions/ArithmeticExpressionTokens.lex

@@ -0,0 +1,70 @@
+%namespace Bts.ArithmeticExpressions
+%scannertype ArithmeticExpressionScanner
+%visibility internal
+%tokentype Token
+
+%option stack, minimize, parser, verbose, persistbuffer, noembedbuffers 
+
+Letter             [a-zA-Z]
+Identifier         {Letter}({Letter}*[0-9]*_*)*
+IntegerConstant    -?[0-9]+
+RealConstant       -?[0-9]+\.[0-9]+
+ParenthesisOpen    \(
+ParenthesisClose   \)
+Add                \+
+Subtract           \-
+Multiply           \*
+Divide             /
+Equals             =
+Comma              ,
+
+%%
+
+{IntegerConstant} {
+   yylval.Integer = int.Parse(yytext);
+   return (int)Token.INTEGER_CONSTANT;
+}
+
+{RealConstant} {
+   yylval.Real = double.Parse(yytext);
+   return (int)Token.REAL_CONSTANT;
+}
+
+{Identifier} {
+   yylval.Identifier = yytext;
+   return (int)Token.IDENTIFIER;
+}
+
+{ParenthesisOpen} {
+   return (int)Token.PARENTHESIS_OPEN;
+}
+
+{ParenthesisClose} {
+   return (int)Token.PARENTHESIS_CLOSE;
+}
+
+{Add} {
+   return (int)Token.ADD;
+}
+
+{Subtract} {
+   return (int)Token.SUBTRACT;
+}
+
+{Multiply} {
+   return (int)Token.MULTIPLY;
+}
+
+{Divide} {
+   return (int)Token.DIVIDE;
+}
+
+{Equals} {
+   return (int)Token.EQUALS;
+}
+
+{Comma} {
+   return (int)Token.COMMA;
+}
+
+%%

src/DataStreamSuite/ArithmeticExpressions/ArithmeticExpressions.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Google.Protobuf" Version="3.24.3" />
+    <PackageReference Include="YaccLexTools" Version="1.2.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ExpressionCore\ExpressionCore.csproj" />
+    <ProjectReference Include="..\..\client\spark_core\spark_core.csproj" />
+  </ItemGroup>
+
+  <ItemGroup Label="ArithmeticExpression">
+    <Scanner Include="ArithmeticExpressionTokens.lex" />
+    <Parser Include="ArithmeticExpressionGrammar.y" />
+  </ItemGroup>
+
+</Project>

src/DataStreamSuite/ArithmeticExpressions/ArithmeticProgram.cs

@@ -0,0 +1,21 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Collections.Immutable;
+
+class ArithmeticProgram : IArithmeticProgram {
+   readonly ImmutableList<Assignment>? assignments;
+
+   public ArithmeticProgram(Assignment assignment) =>
+      assignments = ImmutableList<Assignment>.Empty.Add(assignment);
+
+   public ArithmeticProgram(ImmutableList<Assignment> assignments) =>
+      this.assignments = assignments;
+
+   IEnumerable<string> IArithmeticProgram.OutputIdentifiers =>
+      assignments.empty_if_null()
+         .Select(a => a.Identifier ?? throw new Exception("Identifier string is null"))
+         .Distinct();
+
+   IDictionary<string, object?> IArithmeticProgram.Evaluate(IDictionary<string, object?> env) =>
+      assignments.empty_if_null().Aggregate(env, (e, a) => a.Evaluate(e));
+}

src/DataStreamSuite/ArithmeticExpressions/ArithmeticProgramParser.cs

@@ -0,0 +1,16 @@
+namespace Bts.ArithmeticExpressions;
+
+using Bts.ExpressionCore;
+
+public static class ArithmeticProgramParser {
+   public static IArithmeticProgram Parse(Stream expression) =>
+      new Parser().Parse(expression);
+
+   public static IArithmeticProgram Parse(string expression) =>
+      new Parser().Parse(expression);
+
+   class Parser : IParser<ArithmeticProgram> {
+      public ArithmeticProgram Parse(Stream expression) =>
+         new ArithmeticExpressionParserImpl().Parse(expression).Program;
+   }
+}

src/DataStreamSuite/ArithmeticExpressions/Assignment.cs

@@ -0,0 +1,24 @@
+namespace Bts.ArithmeticExpressions;
+
+public class Assignment {
+   public Assignment(string? identifier, IArithmeticExpression? value) {
+      Identifier = identifier ?? throw new ArgumentNullException(nameof(identifier));
+      Value = value ?? throw new ArgumentNullException(nameof(identifier));
+   }
+
+   public string? Identifier { get; }
+   public IArithmeticExpression? Value { get; }
+
+   public IDictionary<string, object?> Evaluate(IDictionary<string, object?> env) {
+      if (Identifier is null) {
+         throw new InvalidOperationException("Identifier is null");
+      }
+      if (Value is null) {
+         throw new InvalidOperationException($"Value is null (Identifier '{Identifier}')");
+      }
+      env[Identifier] = Value.Evaluate(env) ?? throw new Exception(
+         $"{nameof(Assignment)}.{nameof(Value)} (of type '{Value.GetType()}') " +
+         $"evaluated to null (Identifier '{Identifier}')");
+      return env;
+   }
+}

src/DataStreamSuite/ArithmeticExpressions/Difference.cs

@@ -0,0 +1,45 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Numerics;
+
+public class Difference : IArithmeticExpression<double> {
+   readonly IArithmeticExpression lhs;
+   readonly IArithmeticExpression rhs;
+
+   public Difference(IArithmeticExpression lhs, IArithmeticExpression rhs) {
+      this.lhs = lhs;
+      this.rhs = rhs;
+   }
+
+   public static Difference<T, T, T> Create<T>(
+      IArithmeticExpression<T> left, IArithmeticExpression<T> right)
+      where T : INumber<T>, ISubtractionOperators<T, T, T> =>
+      new(left, right);
+
+   public double Evaluate(IDictionary<string, object?> env) =>
+      evaluateArg(lhs, nameof(lhs), env) - evaluateArg(rhs, nameof(rhs), env);
+
+   static double evaluateArg(
+      IArithmeticExpression expr, string name, IDictionary<string, object?> env) {
+      var obj = expr.Evaluate(env);
+      return ConvertUtils.try_convert(expr.Evaluate(env), out double dbl) ? dbl :
+         throw new Exception(
+            $"Invalid Difference. {name} is of type {obj?.GetType()} (expected {typeof(double)})");
+   }
+}
+
+public class Difference<TLeft, TRight, TResult> : IArithmeticExpression<TResult>
+   where TLeft : INumber<TLeft>, ISubtractionOperators<TLeft, TRight, TResult>
+   where TRight : INumber<TRight>
+   where TResult : INumber<TResult> {
+   readonly IArithmeticExpression<TLeft> left;
+   readonly IArithmeticExpression<TRight> right;
+
+   public Difference(IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right) {
+      this.left = left;
+      this.right = right;
+   }
+
+   public TResult Evaluate(IDictionary<string, object?> env) =>
+      left.Evaluate(env) - right.Evaluate(env);
+}

src/DataStreamSuite/ArithmeticExpressions/EvaluationEnvironment.cs

@@ -0,0 +1,208 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Collections;
+using System.Diagnostics.CodeAnalysis;
+
+class EvaluationEnvironment : IDictionary<string, object?>, IReadOnlyDictionary<string, object?> {
+   IDictionary<string, object?> outerEnv;
+   IDictionary<string, object?> innerEnv = new Dictionary<string, object?>();
+   int? count;
+
+   public EvaluationEnvironment(IDictionary<string, object?> initial) =>
+      outerEnv = initial;
+
+   public object? this[string key] {
+      get {
+         if (innerEnv.TryGetValue(key, out var rv)) {
+            return rv;
+         }
+         if (outerEnv.TryGetValue(key, out rv)) {
+            return rv;
+         }
+         throw new Exception($"Undefined identifier '{key}'");
+      }
+      set {
+         if (count.HasValue && !ContainsKey(key)) {
+            count = count.Value + 1;
+            innerEnv.Add(key, value);
+            return;
+         }
+         innerEnv[key] = value;
+      }
+   }
+
+   public IDictionary<string, object?> Result =>
+      innerEnv;
+
+   public ICollection<string> Keys =>
+      new KeyCollection(outerEnv, innerEnv);
+
+   public ICollection<object?> Values =>
+      new ValueCollection(outerEnv, innerEnv);
+
+   public int Count =>
+      count ??= countKeys(outerEnv, innerEnv);
+
+   public bool IsReadOnly => throw new NotImplementedException();
+
+   public bool ContainsKey(string key) =>
+      innerEnv.ContainsKey(key) || outerEnv.ContainsKey(key);
+
+   public bool TryGetValue(string key, [MaybeNullWhen(false)] out object? value) =>
+      innerEnv.TryGetValue(key, out value) || outerEnv.TryGetValue(key, out value);
+
+   public IEnumerator<KeyValuePair<string, object?>> GetEnumerator() {
+      foreach (var kv in innerEnv) {
+         yield return kv;
+      }
+      foreach (var kv in outerEnv.Except()) {
+         if (!innerEnv.ContainsKey(kv.Key)) {
+            yield return kv;
+         }
+      }
+   }
+
+   public void Add(string key, object? value) {
+      if (ContainsKey(key)) {
+         throw new ArgumentException(
+            $"An element with the same key ({key}) already exists", nameof(key));
+      }
+      innerEnv.Add(key, value);
+   }
+
+   public void Add(KeyValuePair<string, object?> item) =>
+      Add(item.Key, item.Value);
+
+   public void Clear() =>
+      throw new NotSupportedException();
+
+   public bool Contains(KeyValuePair<string, object?> item) =>
+      TryGetValue(item.Key, out var v) && Equals(v, item.Value);
+
+   public void CopyTo(KeyValuePair<string, object?>[] array, int arrayIndex) {
+      foreach (var kv in innerEnv) {
+         array[arrayIndex++] = kv;
+      }
+      foreach (var kv in outerEnv) {
+         if (!innerEnv.ContainsKey(kv.Key)) {
+            array[arrayIndex++] = kv;
+         }
+      }
+   }
+
+   public bool Remove(string key) =>
+      throw new NotSupportedException();
+
+   public bool Remove(KeyValuePair<string, object?> item) =>
+      throw new NotSupportedException();
+
+   static int countKeys(IDictionary<string, object?> d1, IDictionary<string, object?> d2) =>
+      d1.Count > d2.Count ?
+         d1.Count + d2.Keys.WhereNot(d1.ContainsKey).Count() :
+         d2.Count + d1.Keys.WhereNot(d2.ContainsKey).Count();
+
+   IEnumerable<string> IReadOnlyDictionary<string, object?>.Keys => Keys;
+   IEnumerable<object?> IReadOnlyDictionary<string, object?>.Values => Values;
+   IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+   class KeyCollection : ICollection<string> {
+      readonly IDictionary<string, object?> outerEnv;
+      readonly IDictionary<string, object?> innerEnv;
+
+      public KeyCollection(
+         IDictionary<string, object?> outerEnv, IDictionary<string, object?> innerEnv) {
+         this.outerEnv = outerEnv;
+         this.innerEnv = innerEnv;
+      }
+
+      public int Count =>
+         countKeys(outerEnv, innerEnv);
+
+      public bool IsReadOnly => true;
+
+      public void Add(string item) =>
+         throw new NotSupportedException();
+
+      public void Clear() =>
+         throw new NotSupportedException();
+
+      public bool Contains(string item) =>
+         innerEnv.ContainsKey(item) || outerEnv.ContainsKey(item);
+
+      public void CopyTo(string[] array, int arrayIndex) {
+         foreach (var k in this) {
+            array[arrayIndex++] = k;
+         }
+      }
+
+      public IEnumerator<string> GetEnumerator() {
+         foreach (var k in innerEnv.Keys) {
+            yield return k;
+         }
+         foreach (var k in outerEnv.Keys) {
+            if (!innerEnv.ContainsKey(k)) {
+               yield return k;
+            }
+         }
+      }
+
+      public bool Remove(string item) =>
+         throw new NotSupportedException();
+
+      IEnumerator IEnumerable.GetEnumerator() =>
+         GetEnumerator();
+   }
+
+   class ValueCollection : ICollection<object?> {
+      readonly IDictionary<string, object?> outerEnv;
+      readonly IDictionary<string, object?> innerEnv;
+
+      public ValueCollection(
+         IDictionary<string, object?> outerEnv, IDictionary<string, object?> innerEnv) {
+         this.outerEnv = outerEnv;
+         this.innerEnv = innerEnv;
+      }
+
+      public int Count =>
+         // Not a typo (obv, numValues == numKeys)
+         countKeys(outerEnv, innerEnv);
+
+      public bool IsReadOnly => true;
+
+      public void Add(object? item) =>
+         throw new NotSupportedException();
+
+      public void Clear() =>
+         throw new NotSupportedException();
+
+      public bool Contains(object? item) =>
+         innerEnv.Values.Contains(item) ||
+         outerEnv
+            .Where(kv => !innerEnv.ContainsKey(kv.Key))
+            .Select(kv => kv.Value)
+            .Contains(item);
+
+      public void CopyTo(object?[] array, int arrayIndex) {
+         foreach (var k in this) {
+            array[arrayIndex++] = k;
+         }
+      }
+
+      public IEnumerator<object?> GetEnumerator() {
+         foreach (var k in innerEnv.Values) {
+            yield return k;
+         }
+         foreach (var kv in outerEnv) {
+            if (!innerEnv.ContainsKey(kv.Key)) {
+               yield return kv.Value;
+            }
+         }
+      }
+
+      public bool Remove(object? item) =>
+         throw new NotSupportedException();
+
+      IEnumerator IEnumerable.GetEnumerator() =>
+         GetEnumerator();
+   }
+}

src/DataStreamSuite/ArithmeticExpressions/Function.cs

@@ -0,0 +1,34 @@
+namespace Bts.ArithmeticExpressions;
+
+using Spark.Core;
+
+using System.Collections.Immutable;
+using System.Data;
+
+public class Function : IArithmeticExpression {
+   public Function(string? identifier, ImmutableList<IArithmeticExpression>? arguments) {
+      Identifier = identifier;
+      Arguments = arguments;
+   }
+
+   public string? Identifier { get; }
+   public ImmutableList<IArithmeticExpression>? Arguments { get; }
+
+   public object? Evaluate(IDictionary<string, object?> env) {
+      if (Identifier is null) {
+         throw new InvalidOperationException("Identifier is null");
+      }
+      if (Arguments is null) {
+         throw new InvalidOperationException("Arguments is null");
+      }
+      if (Identifier == "ifNull") {
+         throw new NotImplementedException("'ifNull' function not yet implemented");
+      }
+      var argVals = Arguments.Select(e => e.Evaluate(env)).ToArray();
+      var argTypes = Array.ConvertAll(argVals, v => v?.GetType() ?? typeof(object));
+      var method = typeof(Math).GetMethod(Identifier, argTypes) ??
+         throw new EvaluateException(
+            $"Failed to find method '{Identifier}({", ".join(argTypes)})' in {typeof(Math)}");
+      return method.Invoke(null, argVals);
+   }
+}

src/DataStreamSuite/ArithmeticExpressions/GplexBuffers.cs

@@ -0,0 +1,720 @@
+// ==============================================================
+// <auto-generated>
+// This code automatically produced from an embedded resource.
+// Do not edit this file, or it will become incompatible with 
+// the specification from which it was generated.
+// </auto-generated>
+// ==============================================================
+
+using System;
+using System.IO;
+using System.Text;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.Serialization;
+using System.Globalization;
+
+namespace QUT.GplexBuffers
+{
+// Code copied from GPLEX embedded resource
+    [Serializable]
+    internal class BufferException : Exception
+    {
+        public BufferException() { }
+        public BufferException(string message) : base(message) { }
+        public BufferException(string message, Exception innerException)
+            : base(message, innerException) { }
+        protected BufferException(SerializationInfo info, StreamingContext context)
+            : base(info, context) { }
+    }
+
+    internal abstract class ScanBuff
+    {
+        private string fileNm;
+
+        public const int EndOfFile = -1;
+        public const int UnicodeReplacementChar = 0xFFFD;
+
+        public bool IsFile { get { return (fileNm != null); } }
+        public string FileName { get { return fileNm; } set { fileNm = value; } }
+
+        public abstract int Pos { get; set; }
+        public abstract int Read();
+        public virtual void Mark() { }
+
+        public abstract string GetString(int begin, int limit);
+
+        public static ScanBuff GetBuffer(string source)
+        {
+            return new StringBuffer(source);
+        }
+
+        public static ScanBuff GetBuffer(IList<string> source)
+        {
+            return new LineBuffer(source);
+        }
+
+#if (!NOFILES)
+        public static ScanBuff GetBuffer(Stream source)
+        {
+            return new BuildBuffer(source);
+        }
+
+#if (!BYTEMODE)
+        public static ScanBuff GetBuffer(Stream source, int fallbackCodePage)
+        {
+            return new BuildBuffer(source, fallbackCodePage);
+        }
+#endif // !BYTEMODE
+#endif // !NOFILES
+    }
+
+    #region Buffer classes
+
+    // ==============================================================
+    // =====  Definitions for various ScanBuff derived classes   ====
+    // ==============================================================
+    // ===============         String input          ================
+    // ==============================================================
+
+    /// <summary>
+    /// This class reads characters from a single string as
+    /// required, for example, by Visual Studio language services
+    /// </summary>
+    sealed class StringBuffer : ScanBuff
+    {
+        string str;        // input buffer
+        int bPos;          // current position in buffer
+        int sLen;
+
+        public StringBuffer(string source)
+        {
+            this.str = source;
+            this.sLen = source.Length;
+            this.FileName = null;
+        }
+
+        public override int Read()
+        {
+            if (bPos < sLen) return str[bPos++];
+            else if (bPos == sLen) { bPos++; return '\n'; }   // one strike, see new line
+            else { bPos++; return EndOfFile; }                // two strikes and you're out!
+        }
+
+        public override string GetString(int begin, int limit)
+        {
+            //  "limit" can be greater than sLen with the BABEL
+            //  option set.  Read returns a "virtual" EOL if
+            //  an attempt is made to read past the end of the
+            //  string buffer.  Without the guard any attempt 
+            //  to fetch yytext for a token that includes the 
+            //  EOL will throw an index exception.
+            if (limit > sLen) limit = sLen;
+            if (limit <= begin) return "";
+            else return str.Substring(begin, limit - begin);
+        }
+
+        public override int Pos
+        {
+            get { return bPos; }
+            set { bPos = value; }
+        }
+
+        public override string ToString() { return "StringBuffer"; }
+    }
+
+    // ==============================================================
+    //  The LineBuff class contributed by Nigel Horspool, 
+    //  nigelh@cs.uvic.cs
+    // ==============================================================
+
+    sealed class LineBuffer : ScanBuff
+    {
+        IList<string> line;    // list of source lines from a file
+        int numLines;          // number of strings in line list
+        string curLine;        // current line in that list
+        int cLine;             // index of current line in the list
+        int curLen;            // length of current line
+        int curLineStart;      // position of line start in whole file
+        int curLineEnd;        // position of line end in whole file
+        int maxPos;            // max position ever visited in whole file
+        int cPos;              // ordinal number of code in source
+
+        // Constructed from a list of strings, one per source line.
+        // The lines have had trailing '\n' characters removed.
+        public LineBuffer(IList<string> lineList)
+        {
+            line = lineList;
+            numLines = line.Count;
+            cPos = curLineStart = 0;
+            curLine = (numLines > 0 ? line[0] : "");
+            maxPos = curLineEnd = curLen = curLine.Length;
+            cLine = 1;
+            FileName = null;
+        }
+
+        public override int Read()
+        {
+            if (cPos < curLineEnd)
+                return curLine[cPos++ - curLineStart];
+            if (cPos++ == curLineEnd)
+                return '\n';
+            if (cLine >= numLines)
+                return EndOfFile;
+            curLine = line[cLine];
+            curLen = curLine.Length;
+            curLineStart = curLineEnd + 1;
+            curLineEnd = curLineStart + curLen;
+            if (curLineEnd > maxPos)
+                maxPos = curLineEnd;
+            cLine++;
+            return curLen > 0 ? curLine[0] : '\n';
+        }
+
+        // To speed up searches for the line containing a position
+        private int cachedPosition;
+        private int cachedIxdex;
+        private int cachedLineStart;
+
+        // Given a position pos within the entire source, the results are
+        //   ix     -- the index of the containing line
+        //   lstart -- the position of the first character on that line
+        private void findIndex(int pos, out int ix, out int lstart)
+        {
+            if (pos >= cachedPosition)
+            {
+                ix = cachedIxdex; lstart = cachedLineStart;
+            }
+            else
+            {
+                ix = lstart = 0;
+            }
+            while (ix < numLines)
+            {
+                int len = line[ix].Length + 1;
+                if (pos < lstart + len) break;
+                lstart += len;
+                ix++;
+            }
+            cachedPosition = pos;
+            cachedIxdex = ix;
+            cachedLineStart = lstart;
+        }
+
+        public override string GetString(int begin, int limit)
+        {
+            if (begin >= maxPos || limit <= begin) return "";
+            int endIx, begIx, endLineStart, begLineStart;
+            findIndex(begin, out begIx, out begLineStart);
+            int begCol = begin - begLineStart;
+            findIndex(limit, out endIx, out endLineStart);
+            int endCol = limit - endLineStart;
+            string s = line[begIx];
+            if (begIx == endIx)
+            {
+                // the usual case, substring all on one line
+                return (endCol <= s.Length) ?
+                    s.Substring(begCol, endCol - begCol)
+                    : s.Substring(begCol) + "\n";
+            }
+            // the string spans multiple lines, yuk!
+            StringBuilder sb = new StringBuilder();
+            if (begCol < s.Length)
+                sb.Append(s.Substring(begCol));
+            for (; ; )
+            {
+                sb.Append("\n");
+                s = line[++begIx];
+                if (begIx >= endIx) break;
+                sb.Append(s);
+            }
+            if (endCol <= s.Length)
+            {
+                sb.Append(s.Substring(0, endCol));
+            }
+            else
+            {
+                sb.Append(s);
+                sb.Append("\n");
+            }
+            return sb.ToString();
+        }
+
+        public override int Pos
+        {
+            get { return cPos; }
+            set
+            {
+                cPos = value;
+                findIndex(cPos, out cLine, out curLineStart);
+                // cLine should be the *next* line after curLine.
+                curLine = (cLine < numLines ? line[cLine++] : "");
+                curLineEnd = curLineStart + curLine.Length;
+            }
+        }
+
+        public override string ToString() { return "LineBuffer"; }
+    }
+
+#if (!NOFILES)
+    // ==============================================================
+    // =====     class BuildBuff : for unicode text files    ========
+    // ==============================================================
+
+    class BuildBuffer : ScanBuff
+    {
+        // Double buffer for char stream.
+        class BufferElement
+        {
+            StringBuilder bldr = new StringBuilder();
+            StringBuilder next = new StringBuilder();
+            int minIx;
+            int maxIx;
+            int brkIx;
+            bool appendToNext;
+
+            internal BufferElement() { }
+
+            internal int MaxIndex { get { return maxIx; } }
+            // internal int MinIndex { get { return minIx; } }
+
+            internal char this[int index]
+            {
+                get
+                {
+                    if (index < minIx || index >= maxIx)
+                        throw new BufferException("Index was outside data buffer");
+                    else if (index < brkIx)
+                        return bldr[index - minIx];
+                    else
+                        return next[index - brkIx];
+                }
+            }
+
+            internal void Append(char[] block, int count)
+            {
+                maxIx += count;
+                if (appendToNext)
+                    this.next.Append(block, 0, count);
+                else
+                {
+                    this.bldr.Append(block, 0, count);
+                    brkIx = maxIx;
+                    appendToNext = true;
+                }
+            }
+
+            internal string GetString(int start, int limit)
+            {
+                if (limit <= start)
+                    return "";
+                if (start >= minIx && limit <= maxIx)
+                    if (limit < brkIx) // String entirely in bldr builder
+                        return bldr.ToString(start - minIx, limit - start);
+                    else if (start >= brkIx) // String entirely in next builder
+                        return next.ToString(start - brkIx, limit - start);
+                    else // Must do a string-concatenation
+                        return
+                            bldr.ToString(start - minIx, brkIx - start) +
+                            next.ToString(0, limit - brkIx);
+                else
+                    throw new BufferException("String was outside data buffer");
+            }
+
+            internal void Mark(int limit)
+            {
+                if (limit > brkIx + 16) // Rotate blocks
+                {
+                    StringBuilder temp = bldr;
+                    bldr = next;
+                    next = temp;
+                    next.Length = 0;
+                    minIx = brkIx;
+                    brkIx = maxIx;
+                }
+            }
+        }
+
+        BufferElement data = new BufferElement();
+
+        int bPos;            // Postion index in the StringBuilder
+        BlockReader NextBlk; // Delegate that serves char-arrays;
+
+        private string EncodingName
+        {
+            get
+            {
+                StreamReader rdr = NextBlk.Target as StreamReader;
+                return (rdr == null ? "raw-bytes" : rdr.CurrentEncoding.BodyName);
+            }
+        }
+
+        public BuildBuffer(Stream stream)
+        {
+            FileStream fStrm = (stream as FileStream);
+            if (fStrm != null) FileName = fStrm.Name;
+            NextBlk = BlockReaderFactory.Raw(stream);
+        }
+
+#if (!BYTEMODE)
+        public BuildBuffer(Stream stream, int fallbackCodePage)
+        {
+            FileStream fStrm = (stream as FileStream);
+            if (fStrm != null) FileName = fStrm.Name;
+            NextBlk = BlockReaderFactory.Get(stream, fallbackCodePage);
+        }
+#endif
+
+        /// <summary>
+        /// Marks a conservative lower bound for the buffer,
+        /// allowing space to be reclaimed.  If an application 
+        /// needs to call GetString at arbitrary past locations 
+        /// in the input stream, Mark() is not called.
+        /// </summary>
+        public override void Mark() { data.Mark(bPos - 2); }
+
+        public override int Pos
+        {
+            get { return bPos; }
+            set { bPos = value; }
+        }
+
+
+        /// <summary>
+        /// Read returns the ordinal number of the next char, or 
+        /// EOF (-1) for an end of stream.  Note that the next
+        /// code point may require *two* calls of Read().
+        /// </summary>
+        /// <returns></returns>
+        public override int Read()
+        {
+            //
+            //  Characters at positions 
+            //  [data.offset, data.offset + data.bldr.Length)
+            //  are available in data.bldr.
+            //
+            if (bPos < data.MaxIndex)
+            {
+                // ch0 cannot be EOF
+                return (int)data[bPos++];
+            }
+            else // Read from underlying stream
+            {
+                // Experimental code, blocks of page size
+                char[] chrs = new char[4096];
+                int count = NextBlk(chrs, 0, 4096);
+                if (count == 0)
+                    return EndOfFile;
+                else
+                {
+                    data.Append(chrs, count);
+                    return (int)data[bPos++];
+                }
+            }
+        }
+
+        public override string GetString(int begin, int limit)
+        {
+            return data.GetString(begin, limit);
+        }
+
+        public override string ToString()
+        {
+            return "StringBuilder buffer, encoding: " + this.EncodingName;
+        }
+    }
+
+    // =============== End ScanBuff-derived classes ==================
+
+    internal delegate int BlockReader(char[] block, int index, int number);
+
+    // A delegate factory, serving up a delegate that
+    // reads a block of characters from the underlying
+    // encoded stream, via a StreamReader object.
+    //
+    internal static class BlockReaderFactory
+    {
+        public static BlockReader Raw(Stream stream)
+        {
+            return delegate(char[] block, int index, int number)
+            {
+                byte[] b = new byte[number];
+                int count = stream.Read(b, 0, number);
+                int i = 0;
+                int j = index;
+                for (; i < count; i++, j++)
+                    block[j] = (char)b[i];
+                return count;
+            };
+        }
+
+#if (!BYTEMODE)
+        public static BlockReader Get(Stream stream, int fallbackCodePage)
+        {
+            Encoding encoding;
+            int preamble = Preamble(stream);
+
+            if (preamble != 0)  // There is a valid BOM here!
+                encoding = Encoding.GetEncoding(preamble);
+            else if (fallbackCodePage == -1) // Fallback is "raw" bytes
+                return Raw(stream);
+            else if (fallbackCodePage != -2) // Anything but "guess"
+                encoding = Encoding.GetEncoding(fallbackCodePage);
+            else // This is the "guess" option
+            {
+                int guess = new Guesser(stream).GuessCodePage();
+                stream.Seek(0, SeekOrigin.Begin);
+                if (guess == -1) // ==> this is a 7-bit file
+                    encoding = Encoding.ASCII;
+                else if (guess == 65001)
+                    encoding = Encoding.UTF8;
+                else             // ==> use the machine default
+                    encoding = Encoding.Default;
+            }
+            StreamReader reader = new StreamReader(stream, encoding);
+            return reader.Read;
+        }
+
+        static int Preamble(Stream stream)
+        {
+            int b0 = stream.ReadByte();
+            int b1 = stream.ReadByte();
+
+            if (b0 == 0xfe && b1 == 0xff)
+                return 1201; // UTF16BE
+            if (b0 == 0xff && b1 == 0xfe)
+                return 1200; // UTF16LE
+
+            int b2 = stream.ReadByte();
+            if (b0 == 0xef && b1 == 0xbb && b2 == 0xbf)
+                return 65001; // UTF8
+            //
+            // There is no unicode preamble, so we
+            // return denoter for the machine default.
+            //
+            stream.Seek(0, SeekOrigin.Begin);
+            return 0;
+        }
+#endif // !BYTEMODE
+    }
+#endif // !NOFILES
+    #endregion Buffer classes
+
+    // ==============================================================
+    // ============      class CodePageHandling         =============
+    // ==============================================================
+#if (!NOFILES)
+    public static class CodePageHandling
+    {
+        public static int GetCodePage(string option)
+        {
+            string command = option.ToUpperInvariant();
+            if (command.StartsWith("CodePage:", StringComparison.OrdinalIgnoreCase))
+                command = command.Substring(9);
+            try
+            {
+                if (command.Equals("RAW"))
+                    return -1;
+                else if (command.Equals("GUESS"))
+                    return -2;
+                else if (command.Equals("DEFAULT"))
+                    return 0;
+                else if (char.IsDigit(command[0]))
+                    return int.Parse(command, CultureInfo.InvariantCulture);
+                else
+                {
+                    Encoding enc = Encoding.GetEncoding(command);
+                    return enc.CodePage;
+                }
+            }
+            catch (FormatException)
+            {
+                Console.Error.WriteLine(
+                    "Invalid format \"{0}\", using machine default", option);
+            }
+            catch (ArgumentException)
+            {
+                Console.Error.WriteLine(
+                    "Unknown code page \"{0}\", using machine default", option);
+            }
+            return 0;
+        }
+    }
+#region guesser
+#if (!BYTEMODE)
+    // ==============================================================
+    // ============          Encoding Guesser           =============
+    // ==============================================================
+
+    /// <summary>
+    /// This class provides a simple finite state automaton that
+    /// scans the file looking for (1) valid UTF-8 byte patterns,
+    /// (2) bytes >= 0x80 which are not part of a UTF-8 sequence.
+    /// The method then guesses whether it is UTF-8 or maybe some 
+    /// local machine default encoding.  This works well for the
+    /// various Latin encodings.
+    /// </summary>
+    internal class Guesser
+    {
+        ScanBuff buffer;
+
+        public int GuessCodePage() { return Scan(); }
+
+        const int maxAccept = 10;
+        const int initial = 0;
+        const int eofNum = 0;
+        const int goStart = -1;
+        const int INITIAL = 0;
+        const int EndToken = 0;
+
+        #region user code
+        /* 
+         *  Reads the bytes of a file to determine if it is 
+         *  UTF-8 or a single-byte code page file.
+         */
+        public long utfX;
+        public long uppr;
+        #endregion user code
+
+        int state;
+        int currentStart = startState[0];
+        int code;
+
+        #region ScannerTables
+        static int[] startState = new int[] { 11, 0 };
+
+        #region CharacterMap
+        static sbyte[] map = new sbyte[256] {
+/*     '\0' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*   '\x10' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*   '\x20' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      '0' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      '@' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      'P' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      '`' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      'p' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*   '\x80' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\x90' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\xA0' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\xB0' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\xC0' */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
+/*   '\xD0' */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
+/*   '\xE0' */ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 
+/*   '\xF0' */ 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5 };
+        #endregion
+
+        static sbyte[][] nextState = new sbyte[][] {
+            new sbyte[] {0, 0, 0, 0, 0, 0},
+            new sbyte[] {-1, -1, 10, -1, -1, -1},
+            new sbyte[] {-1, -1, -1, -1, -1, -1},
+            new sbyte[] {-1, -1, 8, -1, -1, -1},
+            new sbyte[] {-1, -1, 5, -1, -1, -1},
+            new sbyte[] {-1, -1, 6, -1, -1, -1},
+            new sbyte[] {-1, -1, 7, -1, -1, -1},
+            null,
+            new sbyte[] {-1, -1, 9, -1, -1, -1},
+            null,
+            null,
+            new sbyte[] {-1, 1, 2, 3, 4, 2}
+        };
+
+
+        [SuppressMessage("Microsoft.Performance", "CA1810:InitializeReferenceTypeStaticFieldsInline")]
+        // Reason for suppression: cannot have self-reference in array initializer.
+        static Guesser()
+        {
+            nextState[7] = nextState[2];
+            nextState[9] = nextState[2];
+            nextState[10] = nextState[2];
+        }
+
+        int NextState()
+        {
+            if (code == ScanBuff.EndOfFile)
+                return eofNum;
+            else
+                return nextState[state][map[code]];
+        }
+        #endregion
+
+        public Guesser(System.IO.Stream file) { SetSource(file); }
+
+        public void SetSource(System.IO.Stream source)
+        {
+            this.buffer = new BuildBuffer(source);
+            code = buffer.Read();
+        }
+
+        int Scan()
+        {
+            for (; ; )
+            {
+                int next;
+                state = currentStart;
+                while ((next = NextState()) == goStart)
+                    code = buffer.Read();
+
+                state = next;
+                code = buffer.Read();
+
+                while ((next = NextState()) > eofNum)
+                {
+                    state = next;
+                    code = buffer.Read();
+                }
+                if (state <= maxAccept)
+                {
+                    #region ActionSwitch
+#pragma warning disable 162
+                    switch (state)
+                    {
+                        case eofNum:
+                            switch (currentStart)
+                            {
+                                case 11:
+                                    if (utfX == 0 && uppr == 0) return -1; /* raw ascii */
+                                    else if (uppr * 10 > utfX) return 0;   /* default code page */
+                                    else return 65001;                     /* UTF-8 encoding */
+                                    break;
+                            }
+                            return EndToken;
+                        case 1: // Recognized '{Upper128}',	Shortest string "\xC0"
+                        case 2: // Recognized '{Upper128}',	Shortest string "\x80"
+                        case 3: // Recognized '{Upper128}',	Shortest string "\xE0"
+                        case 4: // Recognized '{Upper128}',	Shortest string "\xF0"
+                            uppr++;
+                            break;
+                        case 5: // Recognized '{Utf8pfx4}{Utf8cont}',	Shortest string "\xF0\x80"
+                            uppr += 2;
+                            break;
+                        case 6: // Recognized '{Utf8pfx4}{Utf8cont}{2}',	Shortest string "\xF0\x80\x80"
+                            uppr += 3;
+                            break;
+                        case 7: // Recognized '{Utf8pfx4}{Utf8cont}{3}',	Shortest string "\xF0\x80\x80\x80"
+                            utfX += 3;
+                            break;
+                        case 8: // Recognized '{Utf8pfx3}{Utf8cont}',	Shortest string "\xE0\x80"
+                            uppr += 2;
+                            break;
+                        case 9: // Recognized '{Utf8pfx3}{Utf8cont}{2}',	Shortest string "\xE0\x80\x80"
+                            utfX += 2;
+                            break;
+                        case 10: // Recognized '{Utf8pfx2}{Utf8cont}',	Shortest string "\xC0\x80"
+                            utfX++;
+                            break;
+                        default:
+                            break;
+                    }
+#pragma warning restore 162
+                    #endregion
+                }
+            }
+        }
+    } // end class Guesser
+    
+#endif // !BYTEMODE
+#endregion
+#endif // !NOFILES
+
+// End of code copied from embedded resource
+}

src/DataStreamSuite/ArithmeticExpressions/IArithmeticExpression.cs

@@ -0,0 +1,19 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Numerics;
+
+public interface IArithmeticExpression {
+   IArithmeticExpression Add(IArithmeticExpression factor) => new Sum(this, factor);
+   IArithmeticExpression Divide(IArithmeticExpression other) => new Quotient(this, other);
+   IArithmeticExpression Multiply(IArithmeticExpression other) => new Product(this, other);
+   IArithmeticExpression Subtract(IArithmeticExpression other) => new Difference(this, other);
+   IArithmeticExpression Negate() => new AdditiveInverse(this);
+   object? Evaluate(IDictionary<string, object?> env);
+}
+
+public interface IArithmeticExpression<T> : IArithmeticExpression where T : INumber<T> {
+   new T Evaluate(IDictionary<string, object?> env);
+
+   object? IArithmeticExpression.Evaluate(IDictionary<string, object?> env) =>
+      Evaluate(env);
+}

src/DataStreamSuite/ArithmeticExpressions/IArithmeticProgram.cs

@@ -0,0 +1,7 @@
+namespace Bts.ArithmeticExpressions;
+
+public interface IArithmeticProgram {
+   IEnumerable<string> OutputIdentifiers { get; }
+
+   IDictionary<string, object?> Evaluate(IDictionary<string, object?> env);
+}

src/DataStreamSuite/ArithmeticExpressions/IntegerConstant.cs

@@ -0,0 +1,11 @@
+namespace Bts.ArithmeticExpressions;
+
+class IntegerConstant : IArithmeticExpression<int> {
+   readonly int value;
+
+   public IntegerConstant(int value) =>
+      this.value = value;
+
+   public int Evaluate(IDictionary<string, object?> env) =>
+      value;
+}

src/DataStreamSuite/ArithmeticExpressions/Product.cs

@@ -0,0 +1,45 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Numerics;
+
+class Product : IArithmeticExpression<double> {
+   readonly IArithmeticExpression left;
+   readonly IArithmeticExpression right;
+
+   public Product(IArithmeticExpression left, IArithmeticExpression right) {
+      this.left = left;
+      this.right = right;
+   }
+
+   public static Product<T, T, T> Create<T>(
+      IArithmeticExpression<T> left, IArithmeticExpression<T> right)
+      where T : INumber<T>, IMultiplyOperators<T, T, T> =>
+      new(left, right);
+
+   public double Evaluate(IDictionary<string, object?> env) =>
+      evaluateArg(left, nameof(left), env) * evaluateArg(right, nameof(right), env);
+
+   static double evaluateArg(
+      IArithmeticExpression expr, string name, IDictionary<string, object?> env) {
+      var obj = expr.Evaluate(env);
+      return ConvertUtils.try_convert(expr.Evaluate(env), out double dbl) ? dbl :
+         throw new Exception(
+            $"Invalid Product. {name} is of type {obj?.GetType()} (expected {typeof(double)})");
+   }
+}
+
+class Product<TLeft, TRight, TResult> : IArithmeticExpression<TResult>
+   where TLeft : INumber<TLeft>, IMultiplyOperators<TLeft, TRight, TResult>
+   where TRight : INumber<TRight>
+   where TResult : INumber<TResult> {
+   readonly IArithmeticExpression<TLeft> left;
+   readonly IArithmeticExpression<TRight> right;
+
+   public Product(IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right) {
+      this.left = left;
+      this.right = right;
+   }
+
+   public TResult Evaluate(IDictionary<string, object?> env) =>
+      left.Evaluate(env) * right.Evaluate(env);
+}

src/DataStreamSuite/ArithmeticExpressions/Quotient.cs

@@ -0,0 +1,45 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Numerics;
+
+class Quotient : IArithmeticExpression<double> {
+   readonly IArithmeticExpression left;
+   readonly IArithmeticExpression right;
+
+   public Quotient(IArithmeticExpression left, IArithmeticExpression right) {
+      this.left = left;
+      this.right = right;
+   }
+
+   public static Quotient<T, T, T> Create<T>(
+      IArithmeticExpression<T> left, IArithmeticExpression<T> right)
+      where T : INumber<T>, IDivisionOperators<T, T, T> =>
+      new(left, right);
+
+   public double Evaluate(IDictionary<string, object?> env) =>
+      evaluateArg(left, nameof(left), env) / evaluateArg(right, nameof(right), env);
+
+   static double evaluateArg(
+      IArithmeticExpression expr, string name, IDictionary<string, object?> env) {
+      var obj = expr.Evaluate(env);
+      return ConvertUtils.try_convert(expr.Evaluate(env), out double dbl) ? dbl :
+         throw new Exception(
+            $"Invalid Quotient. {name} is of type {obj?.GetType()} (expected {typeof(double)})");
+   }
+}
+
+class Quotient<TLeft, TRight, TResult> : IArithmeticExpression<TResult>
+   where TLeft : INumber<TLeft>, IDivisionOperators<TLeft, TRight, TResult>
+   where TRight : INumber<TRight>
+   where TResult : INumber<TResult> {
+   readonly IArithmeticExpression<TLeft> left;
+   readonly IArithmeticExpression<TRight> right;
+
+   public Quotient(IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right) {
+      this.left = left;
+      this.right = right;
+   }
+
+   public TResult Evaluate(IDictionary<string, object?> env) =>
+      left.Evaluate(env) / right.Evaluate(env);
+}

src/DataStreamSuite/ArithmeticExpressions/RealConstant.cs

@@ -0,0 +1,11 @@
+namespace Bts.ArithmeticExpressions;
+
+class RealConstant : IArithmeticExpression<double> {
+   readonly double value;
+
+   public RealConstant(double value) =>
+      this.value = value;
+
+   public double Evaluate(IDictionary<string, object?> env) =>
+      value;
+}

src/DataStreamSuite/ArithmeticExpressions/ShiftReduceParserCode.cs

@@ -0,0 +1,884 @@
+// ==============================================================
+// <auto-generated>
+// This code automatically produced from an embedded resource.
+// Do not edit this file, or it will become incompatible with 
+// the specification from which it was generated.
+// </auto-generated>
+// ==============================================================
+
+// Gardens Point Parser Generator
+// Copyright (c) Wayne Kelly, QUT 2005-2010
+// (see accompanying GPPGcopyright.rtf)
+
+using System;
+using System.Text;
+using System.Globalization;
+using System.Collections.Generic;
+using System.Runtime.Serialization;
+using System.Diagnostics.CodeAnalysis;
+
+namespace QUT.Gppg {
+    /// <summary>
+    /// Abstract class for GPPG shift-reduce parsers.
+    /// Parsers generated by GPPG derive from this base
+    /// class, overriding the abstract Initialize() and
+    /// DoAction() methods.
+    /// </summary>
+    /// <typeparam name="TValue">Semantic value type</typeparam>
+    /// <typeparam name="TSpan">Location type</typeparam>
+#if EXPORT_GPPG
+    public abstract class ShiftReduceParser<TValue, TSpan>
+#else
+    internal abstract class ShiftReduceParser<TValue, TSpan>
+#endif
+ where TSpan : IMerge<TSpan>, new() {
+        private AbstractScanner<TValue, TSpan> scanner;
+        /// <summary>
+        /// The abstract scanner for this parser.
+        /// </summary>
+        protected AbstractScanner<TValue, TSpan> Scanner {
+            get { return scanner; }
+            set { scanner = value; }
+        }
+
+        /// <summary>
+        /// Constructor for base class
+        /// </summary>
+        /// <param name="scanner">Scanner instance for this parser</param>
+        protected ShiftReduceParser( AbstractScanner<TValue, TSpan> scanner ) {
+            this.scanner = scanner;
+        }
+
+        // ==============================================================
+        //                    TECHNICAL EXPLANATION.
+        //   Why the next two fields are not exposed via properties.
+        // ==============================================================
+        // These fields are of the generic parameter types, and are
+        // frequently instantiated as struct types in derived classes.
+        // Semantic actions are defined in the derived classes and refer
+        // to instance fields of these structs.  In such cases the code
+        // "get_CurrentSemanticValue().myField = blah;" will fail since
+        // the getter pushes the value of the field, not the reference.
+        // So, in the presence of properties, gppg would need to encode
+        // such field accesses as ... 
+        //  "tmp = get_CurrentSemanticValue(); // Fetch value
+        //   tmp.myField = blah;               // update
+        //   set_CurrentSemanticValue(tmp); "  // Write update back.
+        // There is no issue if TValue is restricted to be a ref type.
+        // The same explanation applies to scanner.yylval.
+        // ==============================================================
+        /// <summary>
+        /// The current value of the "$$" symbolic variable in the parser
+        /// </summary>
+        [SuppressMessage( "Microsoft.Design", "CA1051:DoNotDeclareVisibleInstanceFields" )]
+        protected TValue CurrentSemanticValue;
+
+        /// <summary>
+        /// The current value of the "@$" symbolic variable in the parser
+        /// </summary>
+        [SuppressMessage( "Microsoft.Design", "CA1051:DoNotDeclareVisibleInstanceFields" )]
+        protected TSpan CurrentLocationSpan;
+        protected int NextToken;
+
+        private TSpan LastSpan;
+        private State FsaState;
+        private bool recovering;
+        private int tokensSinceLastError;
+
+        private PushdownPrefixState<State> StateStack = new PushdownPrefixState<State>();
+        private PushdownPrefixState<TValue> valueStack = new PushdownPrefixState<TValue>();
+        private PushdownPrefixState<TSpan> locationStack = new PushdownPrefixState<TSpan>();
+
+        /// <summary>
+        /// The stack of semantic value (YYSTYPE) values.
+        /// </summary>
+        protected PushdownPrefixState<TValue> ValueStack { get { return valueStack; } }
+
+        /// <summary>
+        /// The stack of location value (YYLTYPE) varlues.
+        /// </summary>
+        protected PushdownPrefixState<TSpan> LocationStack { get { return locationStack; } }
+
+        private int errorToken;
+        private int endOfFileToken;
+        private string[] nonTerminals;
+        private State[] states;
+        private Rule[] rules;
+
+        /// <summary>
+        /// Initialization method to allow derived classes
+        /// to insert the rule list into this base class.
+        /// </summary>
+        /// <param name="rules">The array of Rule objects</param>
+        protected void InitRules( Rule[] rules ) { this.rules = rules; }
+
+        /// <summary>
+        /// Initialization method to allow derived classes to
+        /// insert the states table into this base class.
+        /// </summary>
+        /// <param name="states">The pre-initialized states table</param>
+        protected void InitStates( State[] states ) { this.states = states; }
+
+        /// <summary>
+        /// OBSOLETE FOR VERSION 1.4.0
+        /// </summary>
+        /// <param name="size"></param>
+        protected void InitStateTable( int size ) { states = new State[size]; }
+
+        /// <summary>
+        /// Initialization method to allow derived classes
+        /// to insert the special value for the error and EOF tokens.
+        /// </summary>
+        /// <param name="err">The error state ordinal</param>
+        /// <param name="end">The EOF stat ordinal</param>
+        protected void InitSpecialTokens( int err, int end ) {
+            errorToken = err;
+            endOfFileToken = end;
+        }
+
+        /// <summary>
+        /// Initialization method to allow derived classes to
+        /// insert the non-terminal symbol names into this base class.
+        /// </summary>
+        /// <param name="names">Non-terminal symbol names</param>
+        protected void InitNonTerminals( string[] names ) { nonTerminals = names; }
+
+        #region YYAbort, YYAccept etcetera.
+        [Serializable]
+        [SuppressMessage( "Microsoft.Design", "CA1064:ExceptionsShouldBePublic" )]
+        // Reason for FxCop message suppression -
+        // This exception cannot escape from the local context
+        private class AcceptException : Exception {
+            internal AcceptException() { }
+            protected AcceptException( SerializationInfo i, StreamingContext c ) : base( i, c ) { }
+        }
+        [Serializable]
+        [SuppressMessage( "Microsoft.Design", "CA1064:ExceptionsShouldBePublic" )]
+        // Reason for FxCop message suppression -
+        // This exception cannot escape from the local context
+        private class AbortException : Exception {
+            internal AbortException() { }
+            protected AbortException( SerializationInfo i, StreamingContext c ) : base( i, c ) { }
+        }
+        [Serializable]
+        [SuppressMessage( "Microsoft.Design", "CA1064:ExceptionsShouldBePublic" )]
+        // Reason for FxCop message suppression -
+        // This exception cannot escape from the local context
+        private class ErrorException : Exception {
+            internal ErrorException() { }
+            protected ErrorException( SerializationInfo i, StreamingContext c ) : base( i, c ) { }
+        }
+
+        // The following methods are only called from within
+        // a semantic action. The thrown exceptions can never
+        // propagate outside the ShiftReduceParser class in 
+        // which they are nested.
+
+        /// <summary>
+        /// Force parser to terminate, returning "true"
+        /// </summary>
+        protected static void YYAccept() { throw new AcceptException(); }
+
+        /// <summary>
+        /// Force parser to terminate, returning "false"
+        /// </summary>
+        protected static void YYAbort() { throw new AbortException(); }
+
+        /// <summary>
+        /// Force parser to terminate, returning
+        /// "false" if error recovery fails.
+        /// </summary>
+        protected static void YYError() { throw new ErrorException(); }
+
+        /// <summary>
+        /// Check if parser in error recovery state.
+        /// </summary>
+        protected bool YYRecovering { get { return recovering; } }
+        #endregion
+
+        /// <summary>
+        /// Abstract base method. ShiftReduceParser calls this
+        /// to initialize the base class data structures.  Concrete
+        /// parser classes must override this method.
+        /// </summary>
+        protected abstract void Initialize();
+
+        /// <summary>
+        /// Main entry point of the Shift-Reduce Parser.
+        /// </summary>
+        /// <returns>True if parse succeeds, else false for
+        /// unrecoverable errors</returns>
+        public bool Parse() {
+            Initialize();	// allow derived classes to instantiate rules, states and nonTerminals
+
+            NextToken = 0;
+            FsaState = states[0];
+
+            StateStack.Push( FsaState );
+            valueStack.Push( CurrentSemanticValue );
+            LocationStack.Push( CurrentLocationSpan );
+
+            while (true) {
+#if TRACE_ACTIONS
+                Console.Error.WriteLine("Entering state {0} ", FsaState.number);
+                DisplayStack();
+#endif
+                int action = FsaState.defaultAction;
+
+                if (FsaState.ParserTable != null) {
+                    if (NextToken == 0) {
+                        // We save the last token span, so that the location span
+                        // of production right hand sides that begin or end with a
+                        // nullable production will be correct.
+                        LastSpan = scanner.yylloc;
+                        NextToken = scanner.yylex();
+#if TRACE_ACTIONS
+                       Console.Error.WriteLine( "Reading: Next token is {0}", TerminalToString( NextToken ) );
+#endif
+                    }
+#if TRACE_ACTIONS
+                    else 
+                        Console.Error.WriteLine( "Next token is still {0}", TerminalToString( NextToken ) );
+#endif
+                    if (FsaState.ParserTable.ContainsKey( NextToken ))
+                        action = FsaState.ParserTable[NextToken];
+                }
+
+                if (action > 0)         // shift
+                {
+                    Shift( action );
+                }
+                else if (action < 0)   // reduce
+                {
+                    try {
+                        Reduce( -action );
+                        if (action == -1)	// accept
+                            return true;
+                    }
+                    catch (AbortException) {
+                            return false;
+                    }
+                    catch (AcceptException) {
+                        return true;
+                    }
+                    catch (ErrorException) {
+                        if (!ErrorRecovery())
+                            return false;
+                        else
+                            throw;  // Rethrow x, preserving information.
+                    }
+                }
+                else if (action == 0 && !ErrorRecovery()) // error
+                    return false;
+            }
+        }
+
+        private void Shift( int stateIndex ) {
+#if TRACE_ACTIONS
+				Console.Error.Write("Shifting token {0}, ", TerminalToString(NextToken));
+#endif
+            FsaState = states[stateIndex];
+
+            valueStack.Push( scanner.yylval );
+            StateStack.Push( FsaState );
+            LocationStack.Push( scanner.yylloc );
+
+            if (recovering) {
+                if (NextToken != errorToken)
+                    tokensSinceLastError++;
+
+                if (tokensSinceLastError > 5)
+                    recovering = false;
+            }
+
+            if (NextToken != endOfFileToken)
+                NextToken = 0;
+        }
+
+        private void Reduce( int ruleNumber ) {
+#if TRACE_ACTIONS
+				DisplayRule(ruleNumber);
+#endif
+            Rule rule = rules[ruleNumber];
+            int rhLen = rule.RightHandSide.Length;
+            //
+            //  Default actions for unit productions.
+            //
+            if (rhLen == 1) {
+                CurrentSemanticValue = valueStack.TopElement();   // Default action: $$ = $1;
+                CurrentLocationSpan = LocationStack.TopElement(); // Default action "@$ = @1;
+            }
+            else if (rhLen == 0) {
+                // Create a new blank value.
+                // Explicit semantic action may mutate this value
+                CurrentSemanticValue = default( TValue );
+                // The location span for an empty production will start with the
+                // beginning of the next lexeme, and end with the finish of the
+                // previous lexeme.  This gives the correct behaviour when this
+                // nonsense value is used in later Merge operations.
+                CurrentLocationSpan = (scanner.yylloc != null && LastSpan != null ?
+                    scanner.yylloc.Merge( LastSpan ) :
+                    default( TSpan ));
+            }
+            else {
+                // Default action: $$ = $1;
+                CurrentSemanticValue = valueStack[LocationStack.Depth - rhLen];
+                //  Default action "@$ = @1.Merge(@N)" for location info.
+                TSpan at1 = LocationStack[LocationStack.Depth - rhLen];
+                TSpan atN = LocationStack[LocationStack.Depth - 1];
+                CurrentLocationSpan =
+                    ((at1 != null && atN != null) ? at1.Merge( atN ) : default( TSpan ));
+            }
+
+            DoAction( ruleNumber );
+
+            for (int i = 0; i < rule.RightHandSide.Length; i++) {
+                StateStack.Pop();
+                valueStack.Pop();
+                LocationStack.Pop();
+            }
+            FsaState = StateStack.TopElement();
+
+            if (FsaState.Goto.ContainsKey( rule.LeftHandSide ))
+                FsaState = states[FsaState.Goto[rule.LeftHandSide]];
+
+            StateStack.Push( FsaState );
+            valueStack.Push( CurrentSemanticValue );
+            LocationStack.Push( CurrentLocationSpan );
+        }
+
+        /// <summary>
+        /// Execute the selected action from array.
+        /// Must be overriden in derived classes.
+        /// </summary>
+        /// <param name="actionNumber">Index of the action to perform</param>
+        protected abstract void DoAction( int actionNumber );
+
+        private bool ErrorRecovery() {
+            bool discard;
+
+            if (!recovering) // if not recovering from previous error
+                ReportError();
+
+            if (!FindErrorRecoveryState())
+                return false;
+            //
+            //  The interim fix for the "looping in error recovery"
+            //  artifact involved moving the setting of the recovering 
+            //  bool until after invalid tokens have been discarded.
+            //
+            ShiftErrorToken();
+            discard = DiscardInvalidTokens();
+            recovering = true;
+            tokensSinceLastError = 0;
+            return discard;
+        }
+
+        private void ReportError() {
+            StringBuilder errorMsg = new StringBuilder();
+            errorMsg.AppendFormat( "Syntax error, unexpected {0}", TerminalToString( NextToken ) );
+
+            if (FsaState.ParserTable.Count < 7) {
+                bool first = true;
+                foreach (int terminal in FsaState.ParserTable.Keys) {
+                    if (first)
+                        errorMsg.Append( ", expecting " );
+                    else
+                        errorMsg.Append( ", or " );
+
+                    errorMsg.Append( TerminalToString( terminal ) );
+                    first = false;
+                }
+            }
+            scanner.yyerror( errorMsg.ToString() );
+        }
+
+        private void ShiftErrorToken() {
+            int old_next = NextToken;
+            NextToken = errorToken;
+
+            Shift( FsaState.ParserTable[NextToken] );
+
+#if TRACE_ACTIONS
+				Console.Error.WriteLine("Entering state {0} ", FsaState.number);
+#endif
+            NextToken = old_next;
+        }
+
+        private bool FindErrorRecoveryState() {
+            while (true)    // pop states until one found that accepts error token
+            {
+                if (FsaState.ParserTable != null &&
+                    FsaState.ParserTable.ContainsKey( errorToken ) &&
+                    FsaState.ParserTable[errorToken] > 0) // shift
+                    return true;
+
+#if TRACE_ACTIONS
+					Console.Error.WriteLine("Error: popping state {0}", StateStack.TopElement().number);
+#endif
+                StateStack.Pop();
+                valueStack.Pop();
+                LocationStack.Pop();
+
+#if TRACE_ACTIONS
+			    DisplayStack();
+#endif
+                if (StateStack.IsEmpty()) {
+#if TRACE_ACTIONS
+                        Console.Error.WriteLine("Aborting: didn't find a state that accepts error token");
+#endif
+                    return false;
+                }
+                else
+                    FsaState = StateStack.TopElement();
+            }
+        }
+
+        private bool DiscardInvalidTokens() {
+
+            int action = FsaState.defaultAction;
+
+            if (FsaState.ParserTable != null) {
+                // Discard tokens until find one that works ...
+                while (true) {
+                    if (NextToken == 0) {
+#if TRACE_ACTIONS
+                            Console.Error.Write("Reading a token: ");
+#endif
+                        NextToken = scanner.yylex();
+                    }
+#if TRACE_ACTIONS
+                        Console.Error.WriteLine("Next token is {0}", TerminalToString(NextToken));
+#endif
+                    if (NextToken == endOfFileToken)
+                        return false;
+
+                    if (FsaState.ParserTable.ContainsKey( NextToken ))
+                        action = FsaState.ParserTable[NextToken];
+
+                    if (action != 0)
+                        return true;
+                    else {
+#if TRACE_ACTIONS
+                            Console.Error.WriteLine("Error: Discarding {0}", TerminalToString(NextToken));
+#endif
+                        NextToken = 0;
+                    }
+                }
+            }
+            else if (recovering && tokensSinceLastError == 0) {
+                // 
+                //  Boolean recovering is not set until after the first
+                //  error token has been shifted.  Thus if we get back 
+                //  here with recovering set and no tokens read we are
+                //  looping on the same error recovery action.  This 
+                //  happens if current_state.ParserTable is null because
+                //  the state has an LR(0) reduction, but not all
+                //  lookahead tokens are valid.  This only occurs for
+                //  error productions that *end* on "error".
+                //
+                //  This action discards tokens one at a time until
+                //  the looping stops.  Another attack would be to always
+                //  use the LALR(1) table if a production ends on "error"
+                //
+#if TRACE_ACTIONS
+                    Console.Error.WriteLine("Error: panic discard of {0}", TerminalToString(NextToken));
+#endif
+                if (NextToken == endOfFileToken)
+                    return false;
+                NextToken = 0;
+                return true;
+            }
+            else
+                return true;
+        }
+
+        /// <summary>
+        /// Traditional YACC method.  Discards the next input token.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yyclearin" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yyclearin" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        protected void yyclearin() { NextToken = 0; }
+
+        /// <summary>
+        /// Tradional YACC method. Clear the "recovering" flag.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yyerrok" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yyerrok" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        protected void yyerrok() { recovering = false; }
+
+        /// <summary>
+        /// OBSOLETE FOR VERSION 1.4.0
+        /// Method used by derived types to insert new
+        /// state instances in the "states" array.
+        /// </summary>
+        /// <param name="stateNumber">index of the state</param>
+        /// <param name="state">data for the state</param>
+        protected void AddState( int stateNumber, State state ) {
+            states[stateNumber] = state;
+            state.number = stateNumber;
+        }
+
+        private void DisplayStack() {
+            Console.Error.Write( "State stack is now:" );
+            for (int i = 0; i < StateStack.Depth; i++)
+                Console.Error.Write( " {0}", StateStack[i].number );
+            Console.Error.WriteLine();
+        }
+
+        private void DisplayRule( int ruleNumber ) {
+            Console.Error.Write( "Reducing stack by rule {0}, ", ruleNumber );
+            DisplayProduction( rules[ruleNumber] );
+        }
+
+        private void DisplayProduction( Rule rule ) {
+            if (rule.RightHandSide.Length == 0)
+                Console.Error.Write( "/* empty */ " );
+            else
+                foreach (int symbol in rule.RightHandSide)
+                    Console.Error.Write( "{0} ", SymbolToString( symbol ) );
+
+            Console.Error.WriteLine( "-> {0}", SymbolToString( rule.LeftHandSide ) );
+        }
+
+        /// <summary>
+        /// Abstract state class naming terminal symbols.
+        /// This is overridden by derived classes with the
+        /// name (or alias) to be used in error messages.
+        /// </summary>
+        /// <param name="terminal">The terminal ordinal</param>
+        /// <returns></returns>
+        protected abstract string TerminalToString( int terminal );
+
+        private string SymbolToString( int symbol ) {
+            if (symbol < 0)
+                return nonTerminals[-symbol - 1];
+            else
+                return TerminalToString( symbol );
+        }
+
+        /// <summary>
+        /// Return text representation of argument character
+        /// </summary>
+        /// <param name="input">The character to convert</param>
+        /// <returns>String representation of the character</returns>
+        protected static string CharToString( char input ) {
+            switch (input) {
+                case '\a': return @"'\a'";
+                case '\b': return @"'\b'";
+                case '\f': return @"'\f'";
+                case '\n': return @"'\n'";
+                case '\r': return @"'\r'";
+                case '\t': return @"'\t'";
+                case '\v': return @"'\v'";
+                case '\0': return @"'\0'";
+                default: return string.Format( CultureInfo.InvariantCulture, "'{0}'", input );
+            }
+        }
+    }
+
+    /// <summary>
+    /// Classes implementing this interface must supply a
+    /// method that merges two location objects to return
+    /// a new object of the same type.
+    /// GPPG-generated parsers have the default location
+    /// action equivalent to "@$ = @1.Merge(@N);" where N
+    /// is the right-hand-side length of the production.
+    /// </summary>
+    /// <typeparam name="TSpan">The Location type</typeparam>
+#if EXPORT_GPPG
+    public interface IMerge<TSpan>
+#else
+    internal interface IMerge<TSpan>
+#endif
+ {
+        /// <summary>
+        /// Interface method that creates a location object from
+        /// the current and last object.  Typically used to create
+        /// a location object extending from the start of the @1
+        /// object to the end of the @N object.
+        /// </summary>
+        /// <param name="last">The lexically last object to merge</param>
+        /// <returns>The merged location object</returns>
+        TSpan Merge( TSpan last );
+    }
+
+    /// <summary>
+    /// This is the default class that carries location
+    /// information from the scanner to the parser.
+    /// If you don't declare "%YYLTYPE Foo" the parser
+    /// will expect to deal with this type.
+    /// </summary>
+#if EXPORT_GPPG
+    public class LexLocation : IMerge<LexLocation>
+#else
+    [SuppressMessage( "Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses" )]
+    internal class LexLocation : IMerge<LexLocation>
+#endif
+ {
+        private int startLine;   // start line
+        private int startColumn; // start column
+        private int endLine;     // end line
+        private int endColumn;   // end column
+
+        /// <summary>
+        /// The line at which the text span starts.
+        /// </summary>
+        public int StartLine { get { return startLine; } }
+
+        /// <summary>
+        /// The column at which the text span starts.
+        /// </summary>
+        public int StartColumn { get { return startColumn; } }
+
+        /// <summary>
+        /// The line on which the text span ends.
+        /// </summary>
+        public int EndLine { get { return endLine; } }
+
+        /// <summary>
+        /// The column of the first character
+        /// beyond the end of the text span.
+        /// </summary>
+        public int EndColumn { get { return endColumn; } }
+
+        /// <summary>
+        /// Default no-arg constructor.
+        /// </summary>
+        public LexLocation() { }
+
+        /// <summary>
+        /// Constructor for text-span with given start and end.
+        /// </summary>
+        /// <param name="sl">start line</param>
+        /// <param name="sc">start column</param>
+        /// <param name="el">end line </param>
+        /// <param name="ec">end column</param>
+        public LexLocation( int sl, int sc, int el, int ec ) { startLine = sl; startColumn = sc; endLine = el; endColumn = ec; }
+
+        /// <summary>
+        /// Create a text location which spans from the 
+        /// start of "this" to the end of the argument "last"
+        /// </summary>
+        /// <param name="last">The last location in the result span</param>
+        /// <returns>The merged span</returns>
+        public LexLocation Merge( LexLocation last ) { return new LexLocation( this.startLine, this.startColumn, last.endLine, last.endColumn ); }
+    }
+
+    /// <summary>
+    /// Abstract scanner class that GPPG expects its scanners to 
+    /// extend.
+    /// </summary>
+    /// <typeparam name="TValue">Semantic value type YYSTYPE</typeparam>
+    /// <typeparam name="TSpan">Source location type YYLTYPE</typeparam>
+#if EXPORT_GPPG
+    public abstract class AbstractScanner<TValue, TSpan>
+#else
+    internal abstract class AbstractScanner<TValue, TSpan>
+#endif
+ where TSpan : IMerge<TSpan> {
+        /// <summary>
+        /// Lexical value optionally set by the scanner. The value
+        /// is of the %YYSTYPE type declared in the parser spec.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Design", "CA1051:DoNotDeclareVisibleInstanceFields" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yylval" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yylval" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        // A field must be declared for this value of parametric type,
+        // since it may be instantiated by a value struct.  If it were 
+        // implemented as a property, machine generated code in derived
+        // types would not be able to select on the returned value.
+#pragma warning disable 649
+        public TValue yylval;                     // Lexical value: set by scanner
+#pragma warning restore 649
+
+        /// <summary>
+        /// Current scanner location property. The value is of the
+        /// type declared by %YYLTYPE in the parser specification.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yylloc" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yylloc" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        public virtual TSpan yylloc {
+            get { return default( TSpan ); }       // Empty implementation allowing
+            set { /* skip */ }                   // yylloc to be ignored entirely.
+        }
+
+        /// <summary>
+        /// Main call point for LEX-like scanners.  Returns an int
+        /// corresponding to the token recognized by the scanner.
+        /// </summary>
+        /// <returns>An int corresponding to the token</returns>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yylex" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yylex" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        public abstract int yylex();
+
+        /// <summary>
+        /// Traditional error reporting provided by LEX-like scanners
+        /// to their YACC-like clients.
+        /// </summary>
+        /// <param name="format">Message format string</param>
+        /// <param name="args">Optional array of args</param>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yyerror" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yyerror" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        public virtual void yyerror( string format, params object[] args ) { }
+    }
+
+    /// <summary>
+    /// Encapsulated state for the parser.
+    /// Opaque to users, visible to the tool-generated code.
+    /// </summary>
+#if EXPORT_GPPG
+    public class State
+    {
+        /// <summary>
+        /// The number of states in the automaton.
+        /// </summary>
+        public int number;
+#else
+    internal class State {
+        /// <summary>
+        /// The index of this state in the states array.
+        /// </summary>
+        internal int number;
+#endif
+        internal Dictionary<int, int> ParserTable;   // Terminal -> ParseAction
+        internal Dictionary<int, int> Goto;          // NonTerminal -> State;
+        internal int defaultAction; // = 0;		     // ParseAction
+
+        /// <summary>
+        /// State transition data for this state. Pairs of elements of the 
+        /// goto array associate symbol ordinals with next state indices.
+        /// The actions array is passed to another constructor. 
+        /// </summary>
+        /// <param name="actions">The action list</param>c
+        /// <param name="goToList">Next state data</param>
+        public State( int[] actions, int[] goToList )
+            : this( actions ) {
+            Goto = new Dictionary<int, int>();
+            for (int i = 0; i < goToList.Length; i += 2)
+                Goto.Add( goToList[i], goToList[i + 1] );
+        }
+
+        /// <summary>
+        /// Action data for this state. Pairs of elements of the 
+        /// action array associate action ordinals with each of
+        /// those symbols that have actions in the current state.
+        /// </summary>
+        /// <param name="actions">The action array</param>
+        public State( int[] actions ) {
+            ParserTable = new Dictionary<int, int>();
+            for (int i = 0; i < actions.Length; i += 2)
+                ParserTable.Add( actions[i], actions[i + 1] );
+        }
+
+        /// <summary>
+        /// Set the default action for this state.
+        /// </summary>
+        /// <param name="defaultAction">Ordinal of the default action</param>
+        public State( int defaultAction ) {
+            this.defaultAction = defaultAction;
+        }
+
+        /// <summary>
+        /// Set the default action and the state transition table.
+        /// </summary>
+        /// <param name="defaultAction">The default action</param>
+        /// <param name="goToList">Transitions from this state</param>
+        public State( int defaultAction, int[] goToList )
+            : this( defaultAction ) {
+            Goto = new Dictionary<int, int>();
+            for (int i = 0; i < goToList.Length; i += 2)
+                Goto.Add( goToList[i], goToList[i + 1] );
+        }
+    }
+
+    /// <summary>
+    /// Rule representation at runtime.
+    /// </summary>
+#if EXPORT_GPPG
+    public class Rule
+#else
+    internal class Rule
+#endif
+ {
+        internal int LeftHandSide; // symbol
+        internal int[] RightHandSide; // symbols
+
+        /// <summary>
+        /// Rule constructor.  This holds the ordinal of
+        /// the left hand side symbol, and the list of
+        /// right hand side symbols, in lexical order.
+        /// </summary>
+        /// <param name="left">The LHS non-terminal</param>
+        /// <param name="right">The RHS symbols, in lexical order</param>
+        public Rule( int left, int[] right ) {
+            this.LeftHandSide = left;
+            this.RightHandSide = right;
+        }
+    }
+
+    /// <summary>
+    /// Stack utility for the shift-reduce parser.
+    /// GPPG parsers have three instances:
+    /// (1) The parser state stack, T = QUT.Gppg.State,
+    /// (2) The semantic value stack, T = TValue,
+    /// (3) The location stack, T = TSpan.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+#if EXPORT_GPPG
+    public class PushdownPrefixState<T>
+#else
+    internal class PushdownPrefixState<T>
+#endif
+ {
+        //  Note that we cannot use the BCL Stack<T> class
+        //  here as derived types need to index into stacks.
+        //
+        private T[] array = new T[8];
+        private int tos = 0;
+
+        /// <summary>
+        /// Indexer for values of the stack below the top.
+        /// </summary>
+        /// <param name="index">index of the element, starting from the bottom</param>
+        /// <returns>the selected element</returns>
+        public T this[int index] { get { return array[index]; } }
+
+        /// <summary>
+        /// The current depth of the stack.
+        /// </summary>
+        public int Depth { get { return tos; } }
+
+        internal void Push( T value ) {
+            if (tos >= array.Length) {
+                T[] newarray = new T[array.Length * 2];
+                System.Array.Copy( array, newarray, tos );
+                array = newarray;
+            }
+            array[tos++] = value;
+        }
+
+        internal T Pop() {
+            T rslt = array[--tos];
+            array[tos] = default( T );
+            return rslt;
+        }
+
+        internal T TopElement() { return array[tos - 1]; }
+
+        internal bool IsEmpty() { return tos == 0; }
+    }
+}
+

src/DataStreamSuite/ArithmeticExpressions/Sum.cs

@@ -0,0 +1,45 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Numerics;
+
+class Sum : IArithmeticExpression<double> {
+   readonly IArithmeticExpression left;
+   readonly IArithmeticExpression right;
+
+   public Sum(IArithmeticExpression left, IArithmeticExpression right) {
+      this.left = left;
+      this.right = right;
+   }
+
+   public static Sum<T, T, T> Create<T>(
+      IArithmeticExpression<T> left, IArithmeticExpression<T> right)
+      where T : INumber<T>, IAdditionOperators<T, T, T> =>
+      new(left, right);
+
+   public double Evaluate(IDictionary<string, object?> env) =>
+      evaluateArg(left, nameof(left), env) + evaluateArg(right, nameof(right), env);
+
+   static double evaluateArg(
+      IArithmeticExpression expr, string name, IDictionary<string, object?> env) {
+      var obj = expr.Evaluate(env);
+      return ConvertUtils.try_convert(expr.Evaluate(env), out double dbl) ? dbl :
+         throw new Exception(
+            $"Invalid Sum. {name} is of type {obj?.GetType()} (expected {typeof(double)})");
+   }
+}
+
+class Sum<TLeft, TRight, TResult> : IArithmeticExpression<TResult>
+   where TLeft : INumber<TLeft>, IAdditionOperators<TLeft, TRight, TResult>
+   where TRight : INumber<TRight>
+   where TResult : INumber<TResult> {
+   readonly IArithmeticExpression<TLeft> left;
+   readonly IArithmeticExpression<TRight> right;
+
+   public Sum(IArithmeticExpression<TLeft> left, IArithmeticExpression<TRight> right) {
+      this.left = left;
+      this.right = right;
+   }
+
+   public TResult Evaluate(IDictionary<string, object?> env) =>
+      left.Evaluate(env) + right.Evaluate(env);
+}

src/DataStreamSuite/ArithmeticExpressions/Usings.cs

@@ -0,0 +1,4 @@
+global using System;
+global using System.Linq;
+global using System.Collections.Generic;
+global using System.Collections.Immutable;

src/DataStreamSuite/ArithmeticExpressions/Variable.cs

@@ -0,0 +1,15 @@
+namespace Bts.ArithmeticExpressions;
+
+using System.Collections.Generic;
+
+class Variable : IArithmeticExpression {
+   readonly string identifier;
+
+   public Variable(string identifier) =>
+      this.identifier = identifier;
+
+   public object? Evaluate(IDictionary<string, object?> env) =>
+      env.TryGetValue(identifier, out var val) ? val :
+         throw new KeyNotFoundException(
+            $"Failed to find {nameof(Variable)} '{identifier}'");
+}

src/DataStreamSuite/BaseUtilities/BaseUtilities.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\client\spark_core\spark_core.csproj" />
+  </ItemGroup>
+
+</Project>

src/DataStreamSuite/BaseUtilities/Crono.cs

@@ -0,0 +1,41 @@
+using mbts.spark;
+
+using System;
+using System.Runtime;
+
+namespace BCG.Utilities.General
+{
+	/// <summary>
+	/// Summary description for Crono.
+	/// </summary>
+	public class Crono
+	{
+      public Crono()
+      {
+         myTimer = new HighPerformanceTimer();
+      }
+
+      public void start() 
+      {myTimer.start();}
+
+      public void stop()
+      {myTimer.stop();}
+
+      public TimeSpan time
+      {
+         get 
+         {
+            return new TimeSpan((long) (myTimer.totalMilliseconds * TimeSpan.TicksPerMillisecond));
+         }
+      }
+
+      public double miliseconds
+      {
+         get
+         {return myTimer.totalMilliseconds;}
+      }
+
+      private HighPerformanceTimer myTimer;
+	}
+
+}

src/DataStreamSuite/BlueRegistry/ArrayRegistryHandler.cs

@@ -0,0 +1,60 @@
+using System;
+using Microsoft.Win32;
+
+namespace BCG
+{
+   internal static class ArrayRegistryHandler
+   {
+      public static void setValue (RegistryKey rk, string name, Array array)
+      {
+         rk.SetValue (name, array.Length);
+         Type t = array.GetType ().GetElementType ();
+
+         for (int i = 0; i < array.Length; i++)
+         {
+            if (t == typeof (int))
+               rk.SetValue (string.Concat (name, i.ToString ()), (int) array.GetValue (i));
+            else if (t == typeof (bool))
+               rk.SetValue (string.Concat (name, i.ToString ()), (bool) array.GetValue (i));
+            else
+               rk.SetValue (string.Concat (name, i.ToString ()), array.GetValue (i));
+         }
+      }
+
+      public static Array getValue (RegistryKey rk, string name, Type elementType)
+      {
+         object c = rk.GetValue (name, 0);
+         int count = (int) c;
+
+         Array result;
+
+         if (elementType == typeof (int) || elementType == typeof (System.Int32))
+            result = new int[count];
+         else if (elementType == typeof (bool))
+            result = new bool[count];
+         else if (elementType == typeof (double))
+            result = new double[count];
+         else if (elementType == typeof (DateTime))
+            result = new DateTime[count];
+         else
+            result = new string[count];
+
+         for (int i = 0; i < count; i++)
+         {
+            object val = rk.GetValue (string.Concat (name, i.ToString ()));
+            if (elementType == typeof (int) || elementType == typeof (System.Int32))
+               result.SetValue (int.Parse (val.ToString ()), i);
+            else if (elementType == typeof (bool))
+               result.SetValue (bool.Parse (val.ToString ()), i);
+            else if (elementType == typeof (double))
+               result.SetValue (double.Parse (val.ToString ()), i);
+            else if (elementType == typeof (DateTime))
+               result.SetValue (DateTime.Parse (val.ToString ()), i);
+            else
+               result.SetValue (val.ToString (), i);
+         }
+
+         return result;
+      }
+   }
+}

src/DataStreamSuite/BlueRegistry/BlueRegistry.cs

@@ -0,0 +1,192 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.Concurrent;
+using System.Reflection;
+using Microsoft.Win32;
+
+namespace BCG
+{
+   public enum RegistryRoot { HKCU, HKLM }
+
+   [Serializable]
+   public class BlueRegistry
+   {
+      public const string BlueSubKey = @"Software\Blue Capital Group\";
+      public static readonly string ApplicationPrefix;
+      protected string myFullPath;
+
+      public BlueRegistry(string subPath)
+      {
+         myFullPath = string.Concat(BlueRegistry.ApplicationPrefix, @"\", subPath);
+      }
+
+      public BlueRegistry(BlueRegistry parent, string subPath)
+      {
+         myFullPath = string.Concat(parent.myFullPath, @"\", subPath);
+      }
+
+      static BlueRegistry()
+      {
+         string app = "Applications";
+
+         Assembly ass = Assembly.GetEntryAssembly();
+         if (ass != null)
+         {
+            app = ass.GetName().Name;
+
+            object[] attrs = ass.GetCustomAttributes(
+               Type.GetType("System.Reflection.AssemblyTitleAttribute"), true);
+
+            if (attrs.Length > 0 && ((AssemblyTitleAttribute)attrs[0]).Title != string.Empty)
+            {
+               app = ((AssemblyTitleAttribute)attrs[0]).Title;
+            }
+         }
+
+         ApplicationPrefix = string.Concat(BlueRegistry.BlueSubKey, app);
+      }
+
+      public object getValue(string name)
+      {
+         return getValue(RegistryRoot.HKCU, name);
+      }
+
+      public object getValue(string name, object defaultValue)
+      {
+         return getValue(RegistryRoot.HKCU, name, defaultValue);
+      }
+
+      public void setValue(string name, object value)
+      {
+         setValue(RegistryRoot.HKCU, name, value);
+      }
+
+      public void deleteValue(string name)
+      {
+         deleteValue(RegistryRoot.HKCU, name);
+      }
+
+      private RegistryKey myGetRegistryKey(RegistryRoot root)
+      {
+         if (root == RegistryRoot.HKCU)
+            return Registry.CurrentUser.CreateSubKey(myFullPath);
+         else
+            return Registry.LocalMachine.CreateSubKey(myFullPath);
+      }
+
+      #region Generic Methods
+      internal virtual void setValue(RegistryRoot root, string name, object value)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            rk.SetValue(name, value);
+         }
+      }
+
+      internal virtual object getValue(RegistryRoot root, string name)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            return rk.GetValue(name);
+         }
+      }
+
+      internal virtual void deleteValue(RegistryRoot root, string name)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            rk.DeleteValue(name);
+         }
+      }
+
+      internal virtual object getValue(RegistryRoot root, string name, object defaultValue)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            return rk.GetValue(name, defaultValue);
+         }
+      }
+      #endregion
+
+      #region Double
+      internal virtual void setDouble(RegistryRoot root, string name, double value)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            DoubleRegistryHandler.setValue(rk, name, value);
+         }
+      }
+
+      internal virtual double getDouble(RegistryRoot root, string name)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            return DoubleRegistryHandler.getValue(rk, name);
+         }
+      }
+      #endregion
+
+      #region Enum
+      internal virtual void setEnum(RegistryRoot root, string name, Enum value)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            EnumRegistryHandler.setValue(rk, name, value);
+         }
+      }
+
+      internal virtual Enum getEnum(RegistryRoot root, string name, Type enumType)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            return EnumRegistryHandler.getValue(rk, name, enumType);
+         }
+      }
+      #endregion
+
+      #region Array
+      internal virtual void setArray(RegistryRoot root, string name, Array array)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            ArrayRegistryHandler.setValue(rk, name, array);
+         }
+      }
+
+      internal virtual Array getArray(RegistryRoot root, string name, Type elementType)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            return ArrayRegistryHandler.getValue(rk, name, elementType);
+         }
+      }
+      #endregion
+
+      #region SortedList
+      internal virtual void setSortedList(RegistryRoot root, string name, SortedList slist)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            SortedListRegistryHandler.setValue(rk, name, slist);
+         }
+      }
+
+      internal virtual SortedList getSortedList(RegistryRoot root, string name)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            return SortedListRegistryHandler.getValue(rk, name);
+         }
+      }
+
+      internal virtual void deleteSortedList(RegistryRoot root, string name)
+      {
+         using (RegistryKey rk = myGetRegistryKey(root))
+         {
+            SortedListRegistryHandler.deleteValue(rk, name);
+         }
+      }
+      #endregion
+   }
+}

src/DataStreamSuite/BlueRegistry/BlueRegistry.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net7.0-windows</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <UseWindowsForms>true</UseWindowsForms>
+  </PropertyGroup>
+
+</Project>

src/DataStreamSuite/BlueRegistry/DoubleRegistryHandler.cs

@@ -0,0 +1,22 @@
+using System;
+using Microsoft.Win32;
+
+namespace BCG
+{
+   internal static class DoubleRegistryHandler
+   {
+      public static void setValue (RegistryKey rk, string name, double value)
+      {
+         rk.SetValue (name, value.ToString ());
+      }
+
+      public static double getValue (RegistryKey rk, string name)
+      {
+         object v = rk.GetValue (name);
+         if (v != null) 
+            return double.Parse (v.ToString ());
+         else
+            return double.NaN;
+      }
+   }
+}

src/DataStreamSuite/BlueRegistry/EnumRegistryHandler.cs

@@ -0,0 +1,22 @@
+using System;
+using Microsoft.Win32;
+
+namespace BCG
+{
+   internal static class EnumRegistryHandler
+   {
+      public static void setValue (RegistryKey rk, string name, Enum value)
+      {
+         rk.SetValue (name, value.ToString ());
+      }
+
+      public static Enum getValue (RegistryKey rk, string name, Type enumType)
+      {
+         object v = rk.GetValue (name);
+         if (v != null)
+            return (Enum) Enum.Parse (enumType, v.ToString ());
+         else
+            return null;
+      }
+   }
+}

src/DataStreamSuite/BlueRegistry/PersistWindowState.cs

@@ -0,0 +1,166 @@
+using System;
+using System.Reflection;
+using System.Windows.Forms;
+using System.Drawing;
+using System.Diagnostics;
+using Microsoft.Win32;
+
+namespace BCG
+{
+   public class PersistWindowState
+   {
+      // event info that allows form to persist extra window state data
+      public delegate void WindowStateHandler (object sender, BlueRegistry bluereg);
+      public event WindowStateHandler LoadState;
+      public event WindowStateHandler SaveState;
+
+      private Form myParent;
+      private BlueRegistry myRegistry;
+
+      private int myNormalLeft;
+      private int myNormalTop;
+      private int myNormalWidth;
+      private int myNormalHeight;
+      private bool myResizable = true;
+      private FormWindowState myWindowState;
+      private bool myAllowSaveMinimized = false;
+      private bool mySavePosition = true;
+      private bool mySaveState = true;
+
+      public PersistWindowState (bool savePosition)
+      {
+         mySavePosition = savePosition;
+      }
+
+      public PersistWindowState ()
+      {
+      }
+
+      public bool saveState
+      {
+         [DebuggerStepThrough]
+         set { mySaveState = value; }
+      }
+
+      public Form parent
+      {
+         [DebuggerStepThrough]
+         get { return myParent; }
+         set
+         {
+            myParent = value;
+            myRegistry = new BlueRegistry (myParent.Text);
+
+            // subscribe to parent form's events
+            myParent.Closing += new System.ComponentModel.CancelEventHandler(myOnClosing);
+            myParent.Resize += new System.EventHandler(myOnResize);
+            myParent.Move += new System.EventHandler(myOnMove);
+            myParent.Load += new System.EventHandler(myOnLoad);
+
+            // get initial width and height in case form is never resized
+            myNormalWidth = myParent.Width;
+            myNormalHeight = myParent.Height;
+         }
+      }
+
+      public BlueRegistry blueRegistry
+      {
+         [DebuggerStepThrough]
+         get { return myRegistry; }
+         [DebuggerStepThrough]
+         set { myRegistry = value; }
+      }
+
+      public bool resizable
+      {
+         [DebuggerStepThrough]
+         set { myResizable = value; }
+      }
+
+      public bool allowSaveMinimized
+      {
+         [DebuggerStepThrough]
+         set { myAllowSaveMinimized = value; }
+      }
+
+      private void myOnResize(object sender, System.EventArgs e)
+      {
+         // save width and height
+         if (myParent.WindowState == FormWindowState.Normal && myResizable)
+         {
+            myNormalWidth = myParent.Width;
+            myNormalHeight = myParent.Height;
+         }
+      }
+
+      private void myOnMove(object sender, System.EventArgs e)
+      {
+         // save position
+         if(myParent.WindowState == FormWindowState.Normal)
+         {
+            myNormalLeft = myParent.Left;
+            myNormalTop = myParent.Top;
+         }
+         // save state
+         myWindowState = myParent.WindowState;
+      }
+
+      private void myOnClosing(object sender, System.ComponentModel.CancelEventArgs e)
+      {
+         // save position, size and state
+         if (mySavePosition)
+         {
+            myRegistry.setValue (RegistryRoot.HKCU, "Left", myNormalLeft);
+            myRegistry.setValue (RegistryRoot.HKCU, "Top", myNormalTop);
+         }
+
+         if (myResizable)
+         {
+            myRegistry.setValue (RegistryRoot.HKCU, "Width", myNormalWidth);
+            myRegistry.setValue (RegistryRoot.HKCU, "Height", myNormalHeight);
+         }
+
+         // check if we are allowed to save the state as minimized (not normally)
+         if (!myAllowSaveMinimized)
+         {
+            if(myWindowState == FormWindowState.Minimized)
+               myWindowState = FormWindowState.Normal;
+         }
+
+         if (mySaveState)
+            myRegistry.setValue (RegistryRoot.HKCU, "WindowState", (int) myWindowState);
+        
+         // fire SaveState event
+         if (SaveState != null)
+            SaveState (this, myRegistry);
+      }
+
+      private void myOnLoad (object sender, System.EventArgs e)
+      {
+         if (mySavePosition)
+         {
+            int left = (int) myRegistry.getValue (RegistryRoot.HKCU, "Left", myParent.Left);
+            int top = (int) myRegistry.getValue (RegistryRoot.HKCU, "Top", myParent.Top);
+            myParent.Location = new Point (left, top);
+         }
+
+         if (myResizable)
+         {
+            int width = (int) myRegistry.getValue (RegistryRoot.HKCU, "Width", myParent.Width);
+            int height = (int) myRegistry.getValue (RegistryRoot.HKCU, "Height", myParent.Height);
+            myParent.Size = new Size (width, height);
+         }
+            
+         if (mySaveState)
+         {
+            FormWindowState windowState = (FormWindowState) myRegistry.getValue (RegistryRoot.HKCU, "WindowState", 
+               (int) myParent.WindowState);
+            myParent.WindowState = windowState;
+         }
+
+         // fire LoadState event
+         if(LoadState != null)
+            LoadState (this, myRegistry);
+      }
+   }
+}

src/DataStreamSuite/BlueRegistry/SortedListRegistryHandler.cs

@@ -0,0 +1,58 @@
+using System;
+using System.Collections;
+using Microsoft.Win32;
+
+namespace BCG
+{
+   internal static class SortedListRegistryHandler
+   {
+      public static void setValue (RegistryKey rk, string name, SortedList slist)
+      {
+         rk.SetValue (name, slist.Count);
+               
+         for (int i = 0; i < slist.Count; i++)
+         {
+            object key = slist.GetKey (i);
+            object val = slist.GetByIndex (i);
+            rk.SetValue (string.Concat (name, "_key", i.ToString ()), key);
+            rk.SetValue (string.Concat (name, "_val", i.ToString ()), val);
+         }
+      }
+
+      public static SortedList getValue (RegistryKey rk, string name)
+      {
+         object c = rk.GetValue (name, 0);
+
+         SortedList result = new SortedList ();
+         try
+         {
+            int count = (int) c;
+            for (int i = 0; i < count; i++)
+            {
+               object key = rk.GetValue (string.Concat (name, "_key", i.ToString ()));
+               object val = rk.GetValue (string.Concat (name, "_val", i.ToString ()));
+               result.Add (key, val);
+            }
+         }
+         catch (Exception)
+         {
+            result.Clear ();
+         }
+         return result;
+      }
+
+      public static void deleteValue (RegistryKey rk, string name)
+      {
+         object c = rk.GetValue (name, 0);
+         int count = (int) c;
+
+         for (int i = 0; i < count; i++)
+         {
+            rk.DeleteValue (string.Concat (name, "_key", i.ToString ()), false);
+            rk.DeleteValue (string.Concat (name, "_val", i.ToString ()), false);
+         }
+         
+         rk.DeleteValue (name, false);
+      }
+   }
+}

src/DataStreamSuite/BooleanExpressions/Arguments/Argument.cs

@@ -0,0 +1,21 @@
+namespace Bts.BooleanExpressions.Arguments;
+
+class Argument : IArgument {
+   readonly Func<IDictionary<string, object?>, object?> getValue;
+
+   public Argument(Func<IDictionary<string, object?>, object?> getValue) =>
+      this.getValue = getValue;
+
+   public object? GetValue(IDictionary<string, object?> env) =>
+      getValue(env);
+}
+
+class Argument<T> : IArgument<T> {
+   readonly Func<IDictionary<string, object?>, T> getValue;
+
+   public Argument(Func<IDictionary<string, object?>, T> getValue) =>
+      this.getValue = getValue;
+
+   public T GetValue(IDictionary<string, object?> env) =>
+      getValue(env);
+}

src/DataStreamSuite/BooleanExpressions/Arguments/ArgumentComparer.cs

@@ -0,0 +1,28 @@
+namespace Bts.BooleanExpressions.Arguments;
+
+using bts;
+
+using Spark.Core.Collections;
+
+static class ArgumentComparer {
+   public static int Compare(
+      IArgument value1, IArgument value2, IDictionary<string,object?> env) {
+      if (value1 is null) {
+         throw new ArgumentNullException(nameof(value1));
+      }
+      if (value2 is null) {
+         throw new ArgumentNullException(nameof(value2));
+      }
+      var cmp1 = value1.Cast<IComparable>();
+      var cmp2 = value2.Cast<IComparable>();
+      try {
+         var v1 = cmp1.GetValue(env);
+         var v2 = cmp2.GetValue(env);
+         return v1.GetType().IsNumeric() ?
+            new NumericComparer().Compare(v1, v2) : v1.CompareTo(v2);
+      } catch (Exception ex) {
+         Log.Ui.error($"Comparison failed: {ex}");
+         throw;
+      }
+   }
+}

src/DataStreamSuite/BooleanExpressions/Arguments/ArgumentExtensions.cs

@@ -0,0 +1,11 @@
+namespace Bts.BooleanExpressions.Arguments;
+
+static class ArgumentExtensions {
+   public static IArgument<T> Cast<T>(this IArgument argument) =>
+      new Argument<T>(env => {
+         var obj = argument.GetValue(env);
+         return obj is T t ? t : throw new Exception(
+            $"Expected argument.GetValue to return instance of type {typeof(T)} " +
+            $"(actually {obj?.GetType()})");
+      });
+}

src/DataStreamSuite/BooleanExpressions/Arguments/ArgumentMatcher.cs

@@ -0,0 +1,19 @@
+namespace Bts.BooleanExpressions.Arguments;
+
+using System.Text.RegularExpressions;
+
+static class ArgumentMatcher {
+   public static bool Match(
+      IArgument arg1, IArgument arg2, IDictionary<string, object?> env) {
+      var lobj = arg1.GetValue(env);
+      var robj = arg2.GetValue(env);
+      if (DBNull.Value.Equals(lobj) && robj is string) {
+         return false;
+      }
+      if (lobj is string lstr && robj is string rstr) {
+         return Regex.IsMatch(lstr, rstr);
+      }
+      throw new Exception(
+         $"Type mismatch, cannot string match {lobj?.GetType()} with {robj?.GetType()}");
+   }
+}

src/DataStreamSuite/BooleanExpressions/Arguments/Constant.cs

@@ -0,0 +1,16 @@
+namespace Bts.BooleanExpressions.Arguments;
+
+static class Constant {
+   public static Constant<T> Create<T>(T value) =>
+      new(value);
+}
+
+class Constant<T> : IArgument<T> {
+   readonly T value;
+
+   public Constant(T value) =>
+      this.value = value;
+
+   public T GetValue(IDictionary<string, object?> env) =>
+      value;
+}

src/DataStreamSuite/BooleanExpressions/Arguments/Function.cs

@@ -0,0 +1,29 @@
+namespace Bts.BooleanExpressions.Arguments;
+
+class Function : IArgument {
+   public const string FunctionPrefix = "function:";
+
+   readonly string name;
+   readonly IEnumerable<IArgument> args;
+
+   public Function(string name, IEnumerable<IArgument>? args = null) {
+      this.name = name;
+      this.args = args ?? Enumerable.Empty<IArgument>();
+   }
+
+   public delegate object? Delegate(List<object?> args);
+
+   public object? GetValue(IDictionary<string, object?> env) {
+      var argValues = args?.Select(a => a.GetValue(env))?.ToList() ?? new(0);
+
+      var k = FunctionPrefix + name;
+      if (!env.TryGetValue(k, out var fnObj)) {
+         throw new BooleanExpressionException($"Did not find function named '{name}'");
+      }
+      if (fnObj is not Delegate fn) {
+         throw new BooleanExpressionException(
+            $"Function {name} is not of type {typeof(Delegate)}");
+      }
+      return fn(argValues);
+   }
+}

src/DataStreamSuite/BooleanExpressions/Arguments/IArgument.cs

@@ -0,0 +1,12 @@
+namespace Bts.BooleanExpressions;
+
+interface IArgument {
+   object? GetValue(IDictionary<string, object?> env);
+}
+
+interface IArgument<T> : IArgument {
+   new T GetValue(IDictionary<string, object?> env);
+   
+   object? IArgument.GetValue(IDictionary<string, object?> env) =>
+      GetValue(env);
+}

src/DataStreamSuite/BooleanExpressions/Arguments/Variable.cs

@@ -0,0 +1,12 @@
+namespace Bts.BooleanExpressions.Arguments;
+
+class Variable : IArgument {
+   readonly string name;
+
+   public Variable(string name) =>
+      this.name = name;
+
+   public object? GetValue(IDictionary<string, object?> env) =>
+      env.TryGetValue(name, out var res) ?
+         res : throw new BooleanExpressionException($"Did not find variable named '{name}'");
+}

src/DataStreamSuite/BooleanExpressions/BinaryOperator.cs

@@ -0,0 +1,13 @@
+namespace Bts.BooleanExpressions;
+
+class BinaryOperator : IBinaryOperator {
+   readonly Func<IArgument?, IArgument?, IDictionary<string, object?>, bool> op;
+
+   public BinaryOperator(
+      Func<IArgument?, IArgument?, IDictionary<string, object?>, bool> op) =>
+      this.op = op;
+
+   public bool Evaluate(
+      IArgument? arg1, IArgument? arg2, IDictionary<string, object?> bindings) =>
+      op(arg1, arg2, bindings);
+}

src/DataStreamSuite/BooleanExpressions/BooleanExpression.cs

@@ -0,0 +1,19 @@
+namespace Bts.BooleanExpressions;
+
+using bts;
+
+class BooleanExpression : IBooleanExpression {
+   readonly Func<IDictionary<string, object?>, bool> evaluate;
+
+   public BooleanExpression(Func<IDictionary<string, object?>, bool> evaluate) =>
+      this.evaluate = evaluate;
+
+   public bool Evaluate(IDictionary<string, object?> env) {
+      try {
+         return evaluate(env);
+      } catch (Exception ex) {
+         Log.assert(false, $"BooleanExpression.Evaluate failed: {ex}");
+         throw;
+      }
+   }
+}

src/DataStreamSuite/BooleanExpressions/BooleanExpressionException.cs

@@ -0,0 +1,6 @@
+namespace Bts.BooleanExpressions;
+
+public class BooleanExpressionException : Exception {
+   public BooleanExpressionException(string format, params object[] args)
+      : base(string.Format(format, args)) { }
+}

src/DataStreamSuite/BooleanExpressions/BooleanExpressionGrammar.y

@@ -0,0 +1,176 @@
+%namespace Bts.BooleanExpressions
+%partial
+%visibility internal
+%tokentype Token
+%parsertype BooleanExpressionParserImpl
+
+%union {
+   public int Integer;
+   public double Real;
+   public bool Boolean;
+   public string String;
+   public string Identifier;
+   public DateTime DateTime;
+   public ImmutableList<Definition> Definitions;
+   public Definition Definition;
+   public ImmutableList<string> Parameters;
+   public ImmutableList<IArgument> Arguments;
+   public IArgument Argument;
+   public BooleanExpression Expression;
+   public BoundBooleanExpression BoundExpression;
+}
+
+/* Constants */
+%token BOOLEAN_CONSTANT, INTEGER_CONSTANT, STRING_CONSTANT, NULL_CONSTANT, DATE_TIME_CONSTANT, REAL_CONSTANT
+/* Logical Operators */
+%token OR, AND, XOR, NOT
+/* Syntax */
+%token PARENTHESIS_OPEN, PARENTHESIS_CLOSE, COMMA, IDENTIFIER, DEFINE, BEGIN_DEF, END_DEF
+/* Relational */
+%token EQUAL, LESS_EQUAL, GREATER_EQUAL, LESS, GREATER, DIFFERENT, DIFFERENT2, MATCHES
+
+%left OR AND XOR
+%right NOT
+%nonassoc EQUAL
+
+%type <BoundExpression> BoundExpression
+%type <Definitions> Definitions
+%type <Definition> Definition
+%type <Expression> Expression
+%type <Parameters> Parameters
+%type <Arguments> Arguments
+%type <Argument> Argument
+
+%%
+
+BoundExpression : Definitions Expression { $$ = new($2, $1); }
+   | Expression { $$ = new($1, ImmutableList<Definition>.Empty); };
+
+Definitions :
+   Definition { $$ = ImmutableList<Definition>.Empty.Add($1); }
+   | Definitions Definition { $$ = $1.Add($2); };
+
+Definition :
+   DEFINE IDENTIFIER PARENTHESIS_OPEN Parameters PARENTHESIS_CLOSE BEGIN_DEF Expression END_DEF {
+      $$ = new($2.Identifier, $4, $7);
+   };
+
+Expression :
+   Expression OR Expression {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => left.Evaluate(env) || right.Evaluate(env));
+   }
+   | Expression AND Expression {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => left.Evaluate(env) && right.Evaluate(env));
+   }
+   | Expression XOR Expression {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => left.Evaluate(env) != right.Evaluate(env));
+   }
+   | NOT Expression {
+      var exp = $2;
+      $$ = new(env => !exp.Evaluate(env));
+   }
+   | PARENTHESIS_OPEN Expression PARENTHESIS_CLOSE {
+      $$ = $2; 
+   }
+   | Argument GREATER Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentComparer.Compare(left, right, env) > 0);
+   }
+   | Argument GREATER_EQUAL Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentComparer.Compare(left, right, env) >= 0);
+   }
+   | Argument EQUAL Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentComparer.Compare(left, right, env) == 0);
+   }
+   | Argument LESS_EQUAL Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentComparer.Compare(left, right, env) <= 0);
+   }
+   | Argument LESS Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentComparer.Compare(left, right, env) < 0);
+   }
+   | Argument DIFFERENT Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentComparer.Compare(left, right, env) != 0);
+   }
+   | Argument DIFFERENT2 Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentComparer.Compare(left, right, env) != 0);
+   }
+   | Argument MATCHES Argument {
+      var left = $1;
+      var right = $3;
+      $$ = new(env => Arguments.ArgumentMatcher.Match(left, right, env));
+   }
+   | Argument {
+      var arg = $1;
+      $$ = new(env => (bool)arg.GetValue(env));
+   }
+   ;
+
+Parameters :
+   {
+      $$ = ImmutableList<string>.Empty; 
+   }
+   | IDENTIFIER {
+      $$ = ImmutableList<string>.Empty.Add($1.Identifier); 
+   }
+   | IDENTIFIER COMMA Parameters {
+      $$ = $3.Insert(0, $1.Identifier); 
+   }
+   ;
+
+Arguments :
+   {
+      $$ = ImmutableList<IArgument>.Empty; 
+   }
+   | Argument {
+      $$ = ImmutableList<IArgument>.Empty.Add($1); 
+   }
+   | Arguments COMMA Argument {
+      $$ = $1.Add($3); 
+   }
+   ;
+
+Argument : IDENTIFIER 
+   {
+      $$ = new Arguments.Variable($1.Identifier);
+   }
+   | BOOLEAN_CONSTANT {
+      $$ = Arguments.Constant.Create($1.Boolean); 
+   }
+   | NULL_CONSTANT {
+      $$ = Arguments.Constant.Create(DBNull.Value); 
+   }
+   | REAL_CONSTANT {
+      $$ = Arguments.Constant.Create($1.Real); 
+   }
+   | STRING_CONSTANT {
+      $$ = Arguments.Constant.Create($1.String); 
+   }
+   | INTEGER_CONSTANT {
+      $$ = Arguments.Constant.Create($1.Integer); 
+   }
+   | DATE_TIME_CONSTANT {
+      $$ = Arguments.Constant.Create($1.DateTime); 
+   }
+   | IDENTIFIER PARENTHESIS_OPEN Arguments PARENTHESIS_CLOSE {
+      $$ = new Arguments.Function($1.Identifier, $3); 
+   }
+   ;

src/DataStreamSuite/BooleanExpressions/BooleanExpressionInterpreterException.cs

@@ -0,0 +1,6 @@
+namespace Bts.BooleanExpressions;
+
+public class BooleanExpressionInterpreterException : System.Exception {
+   public BooleanExpressionInterpreterException(string message)
+      : base(message) { }
+}

src/DataStreamSuite/BooleanExpressions/BooleanExpressionParser.cs

@@ -0,0 +1,16 @@
+namespace Bts.BooleanExpressions;
+
+using Bts.ExpressionCore;
+
+public static class BooleanExpressionParser {
+   public static IBooleanExpression Parse(Stream expression) =>
+      new Parser().Parse(expression);
+
+   public static IBooleanExpression Parse(string expression) =>
+      new Parser().Parse(expression);
+
+   class Parser : IParser<IBooleanExpression> {
+      public IBooleanExpression Parse(Stream expression) =>
+         new BooleanExpressionParserImpl().Parse(expression).BoundExpression;
+   }
+}

src/DataStreamSuite/BooleanExpressions/BooleanExpressionParserImpl.cs

@@ -0,0 +1,22 @@
+namespace Bts.BooleanExpressions;
+
+using QUT.Gppg;
+
+using System.IO;
+using System.Text;
+
+partial class BooleanExpressionParserImpl {
+   public BooleanExpressionParserImpl(AbstractScanner<ValueType, LexLocation>? scanner = null)
+      : base(scanner) { }
+
+   public ValueType Parse(string s) {
+      using var ms = new MemoryStream(Encoding.Default.GetBytes(s));
+      return Parse(ms);
+   }
+
+   public ValueType Parse(Stream stream) {
+      Scanner = new BooleanExpressionScanner(stream);
+      Parse();
+      return CurrentSemanticValue;
+   }
+}

src/DataStreamSuite/BooleanExpressions/BooleanExpressionScanner.cs

@@ -0,0 +1,13 @@
+namespace Bts.BooleanExpressions;
+
+using System;
+
+partial class BooleanExpressionScanner {
+   bts.Logger Logger => bts.Log.Gen;
+
+   public override void yyerror(string format, params object[] args) {
+      base.yyerror(format, args);
+      Console.WriteLine(format, args);
+      Console.WriteLine();
+   }
+}

src/DataStreamSuite/BooleanExpressions/BooleanExpressionTokens.lex

@@ -0,0 +1,174 @@
+%namespace Bts.BooleanExpressions
+%scannertype BooleanExpressionScanner
+%visibility internal
+%tokentype Token
+
+%option stack, minimize, parser, verbose, persistbuffer, noembedbuffers 
+
+/* Literal Constants */
+Letter                   [a-zA-Z]
+BooleanConstant          'true'|'false'
+CSStringConstant         \"([^\"\\]*|\\.)*\"
+DateTimeConstant         ([1-9]|'10'|'11'|'12')\/([1-9]|([1-2][0-9])|'30'|'31')\/[0-9][0-9][0-9]*
+IntegerConstant          -?[0-9]+
+NullConstant             'null'
+RealConstant             -?[0-9]+\.[0-9]+
+StringConstant           \'([^\'\\]*|\\.)*\'
+
+/* Relational Operators */
+Equal          =
+LessEqual       <=
+GreaterEqual    >=
+Less            <
+Greater         >
+Different       !=
+Different2      <>
+Matches         ~=
+
+/* Logical Operators */
+Or              or
+And             and
+Not             not
+Xor             xor
+
+Define define
+BeginDef \{
+EndDef \}
+
+Identifier               {Letter}({Letter}*[0-9]*_*)*
+
+/* Utility Tokens */
+OpenParenthesis          \(
+CloseParenthesis         \)
+Comma                    ,
+Negate                   '!'
+MapsTo                   ':'
+IsOfType                 '/'
+
+%%
+
+{StringConstant} {
+   yylval.String = yytext.Substring(1, yytext.Length - 2).Replace(@"\'", "'");
+   return (int)Token.STRING_CONSTANT;
+} 
+
+{BooleanConstant} {
+   yylval.Boolean = yytext.ToLower() switch {
+      "true" => true,
+      "false" => false,
+      _ => throw new Exception(
+         string.Format("Expected yytext to be 'true' or 'false' (actually '{0}')", yytext))
+   };
+   return (int)Token.BOOLEAN_CONSTANT;
+}
+
+{NullConstant} {
+   yylval.Null = DBNull.Value;
+   return (int)Token.NULL_CONSTANT;
+}
+
+{DateTimeConstant} {
+   yylval.DateTime = DateTime.Parse(yytext);
+   return (int)Token.DATE_TIME_CONSTANT;
+}
+
+{IntegerConstant} {
+   yylval.Integer = int.Parse(yytext);
+   return (int)Token.INTEGER_CONSTANT;
+}
+
+{RealConstant} {
+   yylval.Real = double.Parse(yytext);
+   return (int)Token.REAL_CONSTANT;
+}
+
+{OpenParenthesis} {
+   return (int)Token.PARENTHESIS_OPEN;
+}
+
+{CloseParenthesis} {
+   return (int)Token.PARENTHESIS_CLOSE;
+}
+
+{Comma} {
+   return (int)Token.COMMA;
+}
+
+{Negate} {
+   return (int)Token.NEGATE;
+}
+
+{MapsTo} {
+   return (int)Token.MAPS_TO;
+}
+
+{Equal} {
+   return (int)Token.EQUAL;
+}
+
+{LessEqual} {
+   return (int)Token.LESS_EQUAL;
+}
+
+{GreaterEqual} {
+   return (int)Token.GREATER_EQUAL;
+}
+
+{Less} {
+   return (int)Token.LESS;
+}
+
+{Greater} {
+   return (int)Token.GREATER;
+}
+
+{Different} {
+   return (int)Token.DIFFERENT;
+}
+
+{Different2} {
+   return (int)Token.DIFFERENT2;
+}
+
+{Matches} {
+   return (int)Token.MATCHES;
+}
+
+{Or} {
+   return (int)Token.OR;
+}
+
+{And} {
+   return (int)Token.AND;
+}
+
+{Not} {
+   return (int)Token.NOT;
+}
+
+{Xor} {
+   return (int)Token.XOR;
+}
+
+{IsOfType} {
+   return (int)Token.IS_OF_TYPE;
+}
+
+{Define} {
+   return (int)Token.DEFINE;
+}
+
+{BeginDef} {
+   return (int)Token.BEGIN_DEF;
+}
+
+{EndDef} {
+   return (int)Token.END_DEF;
+}
+
+{Identifier} {
+   yylval.Identifier = yytext;
+   return (int)Token.IDENTIFIER;
+}
+
+%%

src/DataStreamSuite/BooleanExpressions/BooleanExpressions.csproj

@@ -2,25 +2,23 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="NUnit" Version="3.13.3" />
+    <PackageReference Include="Google.Protobuf" Version="3.24.3" />
+    <PackageReference Include="YaccLexTools" Version="1.2.0" />
   </ItemGroup>
 
   <ItemGroup>
-    <Reference Include="Tools">
-      <HintPath>$(Externals)\bin\cstools\Tools.dll</HintPath>
-    </Reference>
+    <ProjectReference Include="..\ExpressionCore\ExpressionCore.csproj" />
+    <ProjectReference Include="..\..\client\spark_core\spark_core.csproj" />
   </ItemGroup>
-
+  
   <ItemGroup>
-    <Compile Include="$(DataStreamGrammarDir)\BooleanExpressionTokens.lexer.cs" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <Compile Include="$(DataStreamGrammarDir)\BooleanExpressionSyntax.parser.cs" />
+    <Scanner Include="BooleanExpressionTokens.lex" />
+    <Parser Include="BooleanExpressionGrammar.y" />
   </ItemGroup>
 
 </Project>

src/DataStreamSuite/BooleanExpressions/BoundBooleanExpression.cs

@@ -0,0 +1,32 @@
+namespace Bts.BooleanExpressions;
+
+using Bts.BooleanExpressions.Arguments;
+
+class BoundBooleanExpression : IBooleanExpression {
+   readonly IBooleanExpression expression;
+   readonly IDictionary<string, FunctionDefinition> definitions;
+   readonly Dictionary<string, object?> identifiers;
+
+   public BoundBooleanExpression(
+      IBooleanExpression expression, IEnumerable<Definition>? definitions = null) {
+      this.expression = expression;
+      var defs = definitions ?? Enumerable.Empty<Definition>();
+      identifiers = defs.ToDictionary(
+         kv => kv.id, kv => (object?)kv.exp);
+      this.definitions = extractFunctions(defs).ToDictionary(kv => kv.Key, kv => kv.Value);
+   }
+
+   public bool Evaluate(IDictionary<string, object?> env) {
+      foreach (var kv in env) {
+         identifiers[kv.Key] = kv.Value;
+      }
+      env = new EvaluationEnvironment(identifiers, definitions);
+      return expression.Evaluate(env);
+   }
+
+   static IEnumerable<KeyValuePair<string, FunctionDefinition>> extractFunctions(
+      IEnumerable<Definition> definitions) =>
+      definitions.Select(d =>
+         new KeyValuePair<string, FunctionDefinition>(
+            Function.FunctionPrefix + d.id, new(d.id, d.args.ToList(), d.exp)));
+}

src/DataStreamSuite/BooleanExpressions/Definition.cs

@@ -0,0 +1,18 @@
+namespace Bts.BooleanExpressions;
+
+using System.Collections.Immutable;
+
+public class Definition {
+   public Definition(string id, ImmutableList<string> args, IBooleanExpression exp) {
+      this.id = id;
+      this.args = args;
+      this.exp = exp;
+   }
+
+   public string id { get; }
+   public ImmutableList<string> args { get; }
+   public IBooleanExpression exp { get; }
+
+   public override string ToString() =>
+      $"{id}({string.Join(", ", args)} | {exp?.GetType()})";
+}

src/DataStreamSuite/BooleanExpressions/EvaluationEnvironment.cs

@@ -0,0 +1,123 @@
+namespace Bts.BooleanExpressions;
+
+using Bts.BooleanExpressions.Arguments;
+
+using Spark.Core.Collections;
+
+using System.Collections;
+
+class EvaluationEnvironment : IDictionary<string, object?> {
+   IDictionary<string, object?> userBindings;
+   IDictionary<string, FunctionDefinition> definitions;
+
+   public EvaluationEnvironment(
+      IDictionary<string, object?> userBindings,
+      IDictionary<string, FunctionDefinition> definitions) {
+      this.userBindings = userBindings;
+      this.definitions = definitions;
+   }
+
+   public int Count =>
+      definitions.Count + userBindings.Count;
+
+   public bool IsReadOnly => true;
+
+   public ICollection<string> Keys =>
+      AggregateCollection.Create(userBindings.Keys, definitions.Keys);
+
+   public ICollection<object?> Values =>
+      AggregateCollection.Create(
+         userBindings.Values, SelectorCollection.Create(definitions.Values, v => (object?)v));
+
+   public object? this[string key] {
+      get {
+         var keystr = key.ToString();
+         if (keystr is null || !definitions.TryGetValue(keystr, out var fd)) {
+            return userBindings.TryGetValue(key, out var ubnd) ? ubnd :
+               throw new KeyNotFoundException(
+                  $"EvaluationEnvironment does not contain key '{key}'");
+         }
+         return new Function.Delegate(Evaluate);
+
+         object? Evaluate(List<object?> args) {
+            if (args.Count != fd.args.Count)
+               throw new BooleanExpressionInterpreterException(
+                  $"Parameter count mismatch for {fd.name}. Expected: {fd.args} Got: {args.Count}");
+            else {
+               var newBindings = fd.args.Zip(args).ToDictionary();
+               return fd.expression.Evaluate(new EvaluationEnvironment(
+                  AggregateDictionary.Create(newBindings, userBindings), definitions));
+            }
+         }
+      }
+      set => throw new NotSupportedException();
+   }
+
+   public bool ContainsKey(string key) {
+      var keystr = key.ToString();
+      return
+         (keystr is not null && definitions.ContainsKey(keystr)) ||
+         userBindings.ContainsKey(key);
+   }
+
+   public IEnumerator<KeyValuePair<string, object?>> GetEnumerator() {
+      foreach (var kv in userBindings) {
+         yield return kv;
+      }
+      foreach (var kv in definitions) {
+         if (!userBindings.ContainsKey(kv.Key)) {
+            yield return new(kv.Key, kv.Value);
+         }
+      }
+   }
+
+   public bool TryGetValue(string key, out object? value) {
+      var keystr = key.ToString();
+      if (keystr is null || !definitions.TryGetValue(keystr, out var fd)) {
+         return userBindings.TryGetValue(key, out value);
+      }
+      value = new Function.Delegate(Evaluate);
+      return true;
+
+      object? Evaluate(List<object?> args) {
+         if (args.Count != fd.args.Count)
+            throw new BooleanExpressionInterpreterException(
+               $"Parameter count mismatch for {fd.name}. Expected: {fd.args} Got: {args.Count}");
+         else {
+            var newBindings = fd.args.Zip(args).ToDictionary();
+            return fd.expression.Evaluate(new EvaluationEnvironment(
+               AggregateDictionary.Create(newBindings, userBindings), definitions));
+         }
+      }
+   }
+
+   public void CopyTo(KeyValuePair<string, object?>[] array, int arrayIndex) {
+      foreach (var kv in userBindings) {
+         array[arrayIndex++] = kv;
+      }
+      foreach (var kv in definitions) {
+         array[arrayIndex++] = new(kv.Key, kv.Value);
+      }
+   }
+
+   void IDictionary<string, object?>.Add(string key, object? value) =>
+      throw new NotSupportedException();
+
+   void ICollection<KeyValuePair<string, object?>>.Add(KeyValuePair<string, object?> item) =>
+      throw new NotSupportedException();
+
+   void ICollection<KeyValuePair<string, object?>>.Clear() =>
+      throw new NotSupportedException();
+
+   bool ICollection<KeyValuePair<string, object?>>.Contains(KeyValuePair<string, object?> item) =>
+      TryGetValue(item.Key, out var v) && Equals(v, item.Value);
+
+   IEnumerator IEnumerable.GetEnumerator() =>
+      GetEnumerator();
+
+   bool IDictionary<string, object?>.Remove(string key) =>
+      throw new NotSupportedException();
+
+   bool ICollection<KeyValuePair<string, object?>>.Remove(KeyValuePair<string, object?> item) =>
+      throw new NotSupportedException();
+}

src/DataStreamSuite/BooleanExpressions/FunctionDefinition.cs

@@ -0,0 +1,14 @@
+namespace Bts.BooleanExpressions;
+
+class FunctionDefinition {
+   public FunctionDefinition(
+      string name, IList<string> args, IBooleanExpression expression) {
+      this.name = name;
+      this.args = args;
+      this.expression = expression;
+   }
+
+   public string name { get; }
+   public IList<string> args { get; }
+   public IBooleanExpression expression { get; }
+}

src/DataStreamSuite/BooleanExpressions/GplexBuffers.cs

@@ -0,0 +1,720 @@
+// ==============================================================
+// <auto-generated>
+// This code automatically produced from an embedded resource.
+// Do not edit this file, or it will become incompatible with 
+// the specification from which it was generated.
+// </auto-generated>
+// ==============================================================
+
+using System;
+using System.IO;
+using System.Text;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.Serialization;
+using System.Globalization;
+
+namespace QUT.GplexBuffers
+{
+// Code copied from GPLEX embedded resource
+    [Serializable]
+    internal class BufferException : Exception
+    {
+        public BufferException() { }
+        public BufferException(string message) : base(message) { }
+        public BufferException(string message, Exception innerException)
+            : base(message, innerException) { }
+        protected BufferException(SerializationInfo info, StreamingContext context)
+            : base(info, context) { }
+    }
+
+    internal abstract class ScanBuff
+    {
+        private string fileNm;
+
+        public const int EndOfFile = -1;
+        public const int UnicodeReplacementChar = 0xFFFD;
+
+        public bool IsFile { get { return (fileNm != null); } }
+        public string FileName { get { return fileNm; } set { fileNm = value; } }
+
+        public abstract int Pos { get; set; }
+        public abstract int Read();
+        public virtual void Mark() { }
+
+        public abstract string GetString(int begin, int limit);
+
+        public static ScanBuff GetBuffer(string source)
+        {
+            return new StringBuffer(source);
+        }
+
+        public static ScanBuff GetBuffer(IList<string> source)
+        {
+            return new LineBuffer(source);
+        }
+
+#if (!NOFILES)
+        public static ScanBuff GetBuffer(Stream source)
+        {
+            return new BuildBuffer(source);
+        }
+
+#if (!BYTEMODE)
+        public static ScanBuff GetBuffer(Stream source, int fallbackCodePage)
+        {
+            return new BuildBuffer(source, fallbackCodePage);
+        }
+#endif // !BYTEMODE
+#endif // !NOFILES
+    }
+
+    #region Buffer classes
+
+    // ==============================================================
+    // =====  Definitions for various ScanBuff derived classes   ====
+    // ==============================================================
+    // ===============         String input          ================
+    // ==============================================================
+
+    /// <summary>
+    /// This class reads characters from a single string as
+    /// required, for example, by Visual Studio language services
+    /// </summary>
+    sealed class StringBuffer : ScanBuff
+    {
+        string str;        // input buffer
+        int bPos;          // current position in buffer
+        int sLen;
+
+        public StringBuffer(string source)
+        {
+            this.str = source;
+            this.sLen = source.Length;
+            this.FileName = null;
+        }
+
+        public override int Read()
+        {
+            if (bPos < sLen) return str[bPos++];
+            else if (bPos == sLen) { bPos++; return '\n'; }   // one strike, see new line
+            else { bPos++; return EndOfFile; }                // two strikes and you're out!
+        }
+
+        public override string GetString(int begin, int limit)
+        {
+            //  "limit" can be greater than sLen with the BABEL
+            //  option set.  Read returns a "virtual" EOL if
+            //  an attempt is made to read past the end of the
+            //  string buffer.  Without the guard any attempt 
+            //  to fetch yytext for a token that includes the 
+            //  EOL will throw an index exception.
+            if (limit > sLen) limit = sLen;
+            if (limit <= begin) return "";
+            else return str.Substring(begin, limit - begin);
+        }
+
+        public override int Pos
+        {
+            get { return bPos; }
+            set { bPos = value; }
+        }
+
+        public override string ToString() { return "StringBuffer"; }
+    }
+
+    // ==============================================================
+    //  The LineBuff class contributed by Nigel Horspool, 
+    //  nigelh@cs.uvic.cs
+    // ==============================================================
+
+    sealed class LineBuffer : ScanBuff
+    {
+        IList<string> line;    // list of source lines from a file
+        int numLines;          // number of strings in line list
+        string curLine;        // current line in that list
+        int cLine;             // index of current line in the list
+        int curLen;            // length of current line
+        int curLineStart;      // position of line start in whole file
+        int curLineEnd;        // position of line end in whole file
+        int maxPos;            // max position ever visited in whole file
+        int cPos;              // ordinal number of code in source
+
+        // Constructed from a list of strings, one per source line.
+        // The lines have had trailing '\n' characters removed.
+        public LineBuffer(IList<string> lineList)
+        {
+            line = lineList;
+            numLines = line.Count;
+            cPos = curLineStart = 0;
+            curLine = (numLines > 0 ? line[0] : "");
+            maxPos = curLineEnd = curLen = curLine.Length;
+            cLine = 1;
+            FileName = null;
+        }
+
+        public override int Read()
+        {
+            if (cPos < curLineEnd)
+                return curLine[cPos++ - curLineStart];
+            if (cPos++ == curLineEnd)
+                return '\n';
+            if (cLine >= numLines)
+                return EndOfFile;
+            curLine = line[cLine];
+            curLen = curLine.Length;
+            curLineStart = curLineEnd + 1;
+            curLineEnd = curLineStart + curLen;
+            if (curLineEnd > maxPos)
+                maxPos = curLineEnd;
+            cLine++;
+            return curLen > 0 ? curLine[0] : '\n';
+        }
+
+        // To speed up searches for the line containing a position
+        private int cachedPosition;
+        private int cachedIxdex;
+        private int cachedLineStart;
+
+        // Given a position pos within the entire source, the results are
+        //   ix     -- the index of the containing line
+        //   lstart -- the position of the first character on that line
+        private void findIndex(int pos, out int ix, out int lstart)
+        {
+            if (pos >= cachedPosition)
+            {
+                ix = cachedIxdex; lstart = cachedLineStart;
+            }
+            else
+            {
+                ix = lstart = 0;
+            }
+            while (ix < numLines)
+            {
+                int len = line[ix].Length + 1;
+                if (pos < lstart + len) break;
+                lstart += len;
+                ix++;
+            }
+            cachedPosition = pos;
+            cachedIxdex = ix;
+            cachedLineStart = lstart;
+        }
+
+        public override string GetString(int begin, int limit)
+        {
+            if (begin >= maxPos || limit <= begin) return "";
+            int endIx, begIx, endLineStart, begLineStart;
+            findIndex(begin, out begIx, out begLineStart);
+            int begCol = begin - begLineStart;
+            findIndex(limit, out endIx, out endLineStart);
+            int endCol = limit - endLineStart;
+            string s = line[begIx];
+            if (begIx == endIx)
+            {
+                // the usual case, substring all on one line
+                return (endCol <= s.Length) ?
+                    s.Substring(begCol, endCol - begCol)
+                    : s.Substring(begCol) + "\n";
+            }
+            // the string spans multiple lines, yuk!
+            StringBuilder sb = new StringBuilder();
+            if (begCol < s.Length)
+                sb.Append(s.Substring(begCol));
+            for (; ; )
+            {
+                sb.Append("\n");
+                s = line[++begIx];
+                if (begIx >= endIx) break;
+                sb.Append(s);
+            }
+            if (endCol <= s.Length)
+            {
+                sb.Append(s.Substring(0, endCol));
+            }
+            else
+            {
+                sb.Append(s);
+                sb.Append("\n");
+            }
+            return sb.ToString();
+        }
+
+        public override int Pos
+        {
+            get { return cPos; }
+            set
+            {
+                cPos = value;
+                findIndex(cPos, out cLine, out curLineStart);
+                // cLine should be the *next* line after curLine.
+                curLine = (cLine < numLines ? line[cLine++] : "");
+                curLineEnd = curLineStart + curLine.Length;
+            }
+        }
+
+        public override string ToString() { return "LineBuffer"; }
+    }
+
+#if (!NOFILES)
+    // ==============================================================
+    // =====     class BuildBuff : for unicode text files    ========
+    // ==============================================================
+
+    class BuildBuffer : ScanBuff
+    {
+        // Double buffer for char stream.
+        class BufferElement
+        {
+            StringBuilder bldr = new StringBuilder();
+            StringBuilder next = new StringBuilder();
+            int minIx;
+            int maxIx;
+            int brkIx;
+            bool appendToNext;
+
+            internal BufferElement() { }
+
+            internal int MaxIndex { get { return maxIx; } }
+            // internal int MinIndex { get { return minIx; } }
+
+            internal char this[int index]
+            {
+                get
+                {
+                    if (index < minIx || index >= maxIx)
+                        throw new BufferException("Index was outside data buffer");
+                    else if (index < brkIx)
+                        return bldr[index - minIx];
+                    else
+                        return next[index - brkIx];
+                }
+            }
+
+            internal void Append(char[] block, int count)
+            {
+                maxIx += count;
+                if (appendToNext)
+                    this.next.Append(block, 0, count);
+                else
+                {
+                    this.bldr.Append(block, 0, count);
+                    brkIx = maxIx;
+                    appendToNext = true;
+                }
+            }
+
+            internal string GetString(int start, int limit)
+            {
+                if (limit <= start)
+                    return "";
+                if (start >= minIx && limit <= maxIx)
+                    if (limit < brkIx) // String entirely in bldr builder
+                        return bldr.ToString(start - minIx, limit - start);
+                    else if (start >= brkIx) // String entirely in next builder
+                        return next.ToString(start - brkIx, limit - start);
+                    else // Must do a string-concatenation
+                        return
+                            bldr.ToString(start - minIx, brkIx - start) +
+                            next.ToString(0, limit - brkIx);
+                else
+                    throw new BufferException("String was outside data buffer");
+            }
+
+            internal void Mark(int limit)
+            {
+                if (limit > brkIx + 16) // Rotate blocks
+                {
+                    StringBuilder temp = bldr;
+                    bldr = next;
+                    next = temp;
+                    next.Length = 0;
+                    minIx = brkIx;
+                    brkIx = maxIx;
+                }
+            }
+        }
+
+        BufferElement data = new BufferElement();
+
+        int bPos;            // Postion index in the StringBuilder
+        BlockReader NextBlk; // Delegate that serves char-arrays;
+
+        private string EncodingName
+        {
+            get
+            {
+                StreamReader rdr = NextBlk.Target as StreamReader;
+                return (rdr == null ? "raw-bytes" : rdr.CurrentEncoding.BodyName);
+            }
+        }
+
+        public BuildBuffer(Stream stream)
+        {
+            FileStream fStrm = (stream as FileStream);
+            if (fStrm != null) FileName = fStrm.Name;
+            NextBlk = BlockReaderFactory.Raw(stream);
+        }
+
+#if (!BYTEMODE)
+        public BuildBuffer(Stream stream, int fallbackCodePage)
+        {
+            FileStream fStrm = (stream as FileStream);
+            if (fStrm != null) FileName = fStrm.Name;
+            NextBlk = BlockReaderFactory.Get(stream, fallbackCodePage);
+        }
+#endif
+
+        /// <summary>
+        /// Marks a conservative lower bound for the buffer,
+        /// allowing space to be reclaimed.  If an application 
+        /// needs to call GetString at arbitrary past locations 
+        /// in the input stream, Mark() is not called.
+        /// </summary>
+        public override void Mark() { data.Mark(bPos - 2); }
+
+        public override int Pos
+        {
+            get { return bPos; }
+            set { bPos = value; }
+        }
+
+
+        /// <summary>
+        /// Read returns the ordinal number of the next char, or 
+        /// EOF (-1) for an end of stream.  Note that the next
+        /// code point may require *two* calls of Read().
+        /// </summary>
+        /// <returns></returns>
+        public override int Read()
+        {
+            //
+            //  Characters at positions 
+            //  [data.offset, data.offset + data.bldr.Length)
+            //  are available in data.bldr.
+            //
+            if (bPos < data.MaxIndex)
+            {
+                // ch0 cannot be EOF
+                return (int)data[bPos++];
+            }
+            else // Read from underlying stream
+            {
+                // Experimental code, blocks of page size
+                char[] chrs = new char[4096];
+                int count = NextBlk(chrs, 0, 4096);
+                if (count == 0)
+                    return EndOfFile;
+                else
+                {
+                    data.Append(chrs, count);
+                    return (int)data[bPos++];
+                }
+            }
+        }
+
+        public override string GetString(int begin, int limit)
+        {
+            return data.GetString(begin, limit);
+        }
+
+        public override string ToString()
+        {
+            return "StringBuilder buffer, encoding: " + this.EncodingName;
+        }
+    }
+
+    // =============== End ScanBuff-derived classes ==================
+
+    internal delegate int BlockReader(char[] block, int index, int number);
+
+    // A delegate factory, serving up a delegate that
+    // reads a block of characters from the underlying
+    // encoded stream, via a StreamReader object.
+    //
+    internal static class BlockReaderFactory
+    {
+        public static BlockReader Raw(Stream stream)
+        {
+            return delegate(char[] block, int index, int number)
+            {
+                byte[] b = new byte[number];
+                int count = stream.Read(b, 0, number);
+                int i = 0;
+                int j = index;
+                for (; i < count; i++, j++)
+                    block[j] = (char)b[i];
+                return count;
+            };
+        }
+
+#if (!BYTEMODE)
+        public static BlockReader Get(Stream stream, int fallbackCodePage)
+        {
+            Encoding encoding;
+            int preamble = Preamble(stream);
+
+            if (preamble != 0)  // There is a valid BOM here!
+                encoding = Encoding.GetEncoding(preamble);
+            else if (fallbackCodePage == -1) // Fallback is "raw" bytes
+                return Raw(stream);
+            else if (fallbackCodePage != -2) // Anything but "guess"
+                encoding = Encoding.GetEncoding(fallbackCodePage);
+            else // This is the "guess" option
+            {
+                int guess = new Guesser(stream).GuessCodePage();
+                stream.Seek(0, SeekOrigin.Begin);
+                if (guess == -1) // ==> this is a 7-bit file
+                    encoding = Encoding.ASCII;
+                else if (guess == 65001)
+                    encoding = Encoding.UTF8;
+                else             // ==> use the machine default
+                    encoding = Encoding.Default;
+            }
+            StreamReader reader = new StreamReader(stream, encoding);
+            return reader.Read;
+        }
+
+        static int Preamble(Stream stream)
+        {
+            int b0 = stream.ReadByte();
+            int b1 = stream.ReadByte();
+
+            if (b0 == 0xfe && b1 == 0xff)
+                return 1201; // UTF16BE
+            if (b0 == 0xff && b1 == 0xfe)
+                return 1200; // UTF16LE
+
+            int b2 = stream.ReadByte();
+            if (b0 == 0xef && b1 == 0xbb && b2 == 0xbf)
+                return 65001; // UTF8
+            //
+            // There is no unicode preamble, so we
+            // return denoter for the machine default.
+            //
+            stream.Seek(0, SeekOrigin.Begin);
+            return 0;
+        }
+#endif // !BYTEMODE
+    }
+#endif // !NOFILES
+    #endregion Buffer classes
+
+    // ==============================================================
+    // ============      class CodePageHandling         =============
+    // ==============================================================
+#if (!NOFILES)
+    public static class CodePageHandling
+    {
+        public static int GetCodePage(string option)
+        {
+            string command = option.ToUpperInvariant();
+            if (command.StartsWith("CodePage:", StringComparison.OrdinalIgnoreCase))
+                command = command.Substring(9);
+            try
+            {
+                if (command.Equals("RAW"))
+                    return -1;
+                else if (command.Equals("GUESS"))
+                    return -2;
+                else if (command.Equals("DEFAULT"))
+                    return 0;
+                else if (char.IsDigit(command[0]))
+                    return int.Parse(command, CultureInfo.InvariantCulture);
+                else
+                {
+                    Encoding enc = Encoding.GetEncoding(command);
+                    return enc.CodePage;
+                }
+            }
+            catch (FormatException)
+            {
+                Console.Error.WriteLine(
+                    "Invalid format \"{0}\", using machine default", option);
+            }
+            catch (ArgumentException)
+            {
+                Console.Error.WriteLine(
+                    "Unknown code page \"{0}\", using machine default", option);
+            }
+            return 0;
+        }
+    }
+#region guesser
+#if (!BYTEMODE)
+    // ==============================================================
+    // ============          Encoding Guesser           =============
+    // ==============================================================
+
+    /// <summary>
+    /// This class provides a simple finite state automaton that
+    /// scans the file looking for (1) valid UTF-8 byte patterns,
+    /// (2) bytes >= 0x80 which are not part of a UTF-8 sequence.
+    /// The method then guesses whether it is UTF-8 or maybe some 
+    /// local machine default encoding.  This works well for the
+    /// various Latin encodings.
+    /// </summary>
+    internal class Guesser
+    {
+        ScanBuff buffer;
+
+        public int GuessCodePage() { return Scan(); }
+
+        const int maxAccept = 10;
+        const int initial = 0;
+        const int eofNum = 0;
+        const int goStart = -1;
+        const int INITIAL = 0;
+        const int EndToken = 0;
+
+        #region user code
+        /* 
+         *  Reads the bytes of a file to determine if it is 
+         *  UTF-8 or a single-byte code page file.
+         */
+        public long utfX;
+        public long uppr;
+        #endregion user code
+
+        int state;
+        int currentStart = startState[0];
+        int code;
+
+        #region ScannerTables
+        static int[] startState = new int[] { 11, 0 };
+
+        #region CharacterMap
+        static sbyte[] map = new sbyte[256] {
+/*     '\0' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*   '\x10' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*   '\x20' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      '0' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      '@' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      'P' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      '`' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*      'p' */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
+/*   '\x80' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\x90' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\xA0' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\xB0' */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
+/*   '\xC0' */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
+/*   '\xD0' */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
+/*   '\xE0' */ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 
+/*   '\xF0' */ 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5 };
+        #endregion
+
+        static sbyte[][] nextState = new sbyte[][] {
+            new sbyte[] {0, 0, 0, 0, 0, 0},
+            new sbyte[] {-1, -1, 10, -1, -1, -1},
+            new sbyte[] {-1, -1, -1, -1, -1, -1},
+            new sbyte[] {-1, -1, 8, -1, -1, -1},
+            new sbyte[] {-1, -1, 5, -1, -1, -1},
+            new sbyte[] {-1, -1, 6, -1, -1, -1},
+            new sbyte[] {-1, -1, 7, -1, -1, -1},
+            null,
+            new sbyte[] {-1, -1, 9, -1, -1, -1},
+            null,
+            null,
+            new sbyte[] {-1, 1, 2, 3, 4, 2}
+        };
+
+
+        [SuppressMessage("Microsoft.Performance", "CA1810:InitializeReferenceTypeStaticFieldsInline")]
+        // Reason for suppression: cannot have self-reference in array initializer.
+        static Guesser()
+        {
+            nextState[7] = nextState[2];
+            nextState[9] = nextState[2];
+            nextState[10] = nextState[2];
+        }
+
+        int NextState()
+        {
+            if (code == ScanBuff.EndOfFile)
+                return eofNum;
+            else
+                return nextState[state][map[code]];
+        }
+        #endregion
+
+        public Guesser(System.IO.Stream file) { SetSource(file); }
+
+        public void SetSource(System.IO.Stream source)
+        {
+            this.buffer = new BuildBuffer(source);
+            code = buffer.Read();
+        }
+
+        int Scan()
+        {
+            for (; ; )
+            {
+                int next;
+                state = currentStart;
+                while ((next = NextState()) == goStart)
+                    code = buffer.Read();
+
+                state = next;
+                code = buffer.Read();
+
+                while ((next = NextState()) > eofNum)
+                {
+                    state = next;
+                    code = buffer.Read();
+                }
+                if (state <= maxAccept)
+                {
+                    #region ActionSwitch
+#pragma warning disable 162
+                    switch (state)
+                    {
+                        case eofNum:
+                            switch (currentStart)
+                            {
+                                case 11:
+                                    if (utfX == 0 && uppr == 0) return -1; /* raw ascii */
+                                    else if (uppr * 10 > utfX) return 0;   /* default code page */
+                                    else return 65001;                     /* UTF-8 encoding */
+                                    break;
+                            }
+                            return EndToken;
+                        case 1: // Recognized '{Upper128}',	Shortest string "\xC0"
+                        case 2: // Recognized '{Upper128}',	Shortest string "\x80"
+                        case 3: // Recognized '{Upper128}',	Shortest string "\xE0"
+                        case 4: // Recognized '{Upper128}',	Shortest string "\xF0"
+                            uppr++;
+                            break;
+                        case 5: // Recognized '{Utf8pfx4}{Utf8cont}',	Shortest string "\xF0\x80"
+                            uppr += 2;
+                            break;
+                        case 6: // Recognized '{Utf8pfx4}{Utf8cont}{2}',	Shortest string "\xF0\x80\x80"
+                            uppr += 3;
+                            break;
+                        case 7: // Recognized '{Utf8pfx4}{Utf8cont}{3}',	Shortest string "\xF0\x80\x80\x80"
+                            utfX += 3;
+                            break;
+                        case 8: // Recognized '{Utf8pfx3}{Utf8cont}',	Shortest string "\xE0\x80"
+                            uppr += 2;
+                            break;
+                        case 9: // Recognized '{Utf8pfx3}{Utf8cont}{2}',	Shortest string "\xE0\x80\x80"
+                            utfX += 2;
+                            break;
+                        case 10: // Recognized '{Utf8pfx2}{Utf8cont}',	Shortest string "\xC0\x80"
+                            utfX++;
+                            break;
+                        default:
+                            break;
+                    }
+#pragma warning restore 162
+                    #endregion
+                }
+            }
+        }
+    } // end class Guesser
+    
+#endif // !BYTEMODE
+#endregion
+#endif // !NOFILES
+
+// End of code copied from embedded resource
+}

src/DataStreamSuite/BooleanExpressions/IBinaryOperator.cs

@@ -0,0 +1,5 @@
+namespace Bts.BooleanExpressions;
+
+interface IBinaryOperator {
+   bool Evaluate(IArgument? left, IArgument? right, IDictionary<string, object?> env);
+}

src/DataStreamSuite/BooleanExpressions/IBooleanExpression.cs

@@ -0,0 +1,5 @@
+namespace Bts.BooleanExpressions;
+
+public interface IBooleanExpression {
+   bool Evaluate(IDictionary<string, object?> env);
+}

src/DataStreamSuite/BooleanExpressions/ShiftReduceParserCode.cs

@@ -0,0 +1,884 @@
+// ==============================================================
+// <auto-generated>
+// This code automatically produced from an embedded resource.
+// Do not edit this file, or it will become incompatible with 
+// the specification from which it was generated.
+// </auto-generated>
+// ==============================================================
+
+// Gardens Point Parser Generator
+// Copyright (c) Wayne Kelly, QUT 2005-2010
+// (see accompanying GPPGcopyright.rtf)
+
+using System;
+using System.Text;
+using System.Globalization;
+using System.Collections.Generic;
+using System.Runtime.Serialization;
+using System.Diagnostics.CodeAnalysis;
+
+namespace QUT.Gppg {
+    /// <summary>
+    /// Abstract class for GPPG shift-reduce parsers.
+    /// Parsers generated by GPPG derive from this base
+    /// class, overriding the abstract Initialize() and
+    /// DoAction() methods.
+    /// </summary>
+    /// <typeparam name="TValue">Semantic value type</typeparam>
+    /// <typeparam name="TSpan">Location type</typeparam>
+#if EXPORT_GPPG
+    public abstract class ShiftReduceParser<TValue, TSpan>
+#else
+    internal abstract class ShiftReduceParser<TValue, TSpan>
+#endif
+ where TSpan : IMerge<TSpan>, new() {
+        private AbstractScanner<TValue, TSpan> scanner;
+        /// <summary>
+        /// The abstract scanner for this parser.
+        /// </summary>
+        protected AbstractScanner<TValue, TSpan> Scanner {
+            get { return scanner; }
+            set { scanner = value; }
+        }
+
+        /// <summary>
+        /// Constructor for base class
+        /// </summary>
+        /// <param name="scanner">Scanner instance for this parser</param>
+        protected ShiftReduceParser( AbstractScanner<TValue, TSpan> scanner ) {
+            this.scanner = scanner;
+        }
+
+        // ==============================================================
+        //                    TECHNICAL EXPLANATION.
+        //   Why the next two fields are not exposed via properties.
+        // ==============================================================
+        // These fields are of the generic parameter types, and are
+        // frequently instantiated as struct types in derived classes.
+        // Semantic actions are defined in the derived classes and refer
+        // to instance fields of these structs.  In such cases the code
+        // "get_CurrentSemanticValue().myField = blah;" will fail since
+        // the getter pushes the value of the field, not the reference.
+        // So, in the presence of properties, gppg would need to encode
+        // such field accesses as ... 
+        //  "tmp = get_CurrentSemanticValue(); // Fetch value
+        //   tmp.myField = blah;               // update
+        //   set_CurrentSemanticValue(tmp); "  // Write update back.
+        // There is no issue if TValue is restricted to be a ref type.
+        // The same explanation applies to scanner.yylval.
+        // ==============================================================
+        /// <summary>
+        /// The current value of the "$$" symbolic variable in the parser
+        /// </summary>
+        [SuppressMessage( "Microsoft.Design", "CA1051:DoNotDeclareVisibleInstanceFields" )]
+        protected TValue CurrentSemanticValue;
+
+        /// <summary>
+        /// The current value of the "@$" symbolic variable in the parser
+        /// </summary>
+        [SuppressMessage( "Microsoft.Design", "CA1051:DoNotDeclareVisibleInstanceFields" )]
+        protected TSpan CurrentLocationSpan;
+        protected int NextToken;
+
+        private TSpan LastSpan;
+        private State FsaState;
+        private bool recovering;
+        private int tokensSinceLastError;
+
+        private PushdownPrefixState<State> StateStack = new PushdownPrefixState<State>();
+        private PushdownPrefixState<TValue> valueStack = new PushdownPrefixState<TValue>();
+        private PushdownPrefixState<TSpan> locationStack = new PushdownPrefixState<TSpan>();
+
+        /// <summary>
+        /// The stack of semantic value (YYSTYPE) values.
+        /// </summary>
+        protected PushdownPrefixState<TValue> ValueStack { get { return valueStack; } }
+
+        /// <summary>
+        /// The stack of location value (YYLTYPE) varlues.
+        /// </summary>
+        protected PushdownPrefixState<TSpan> LocationStack { get { return locationStack; } }
+
+        private int errorToken;
+        private int endOfFileToken;
+        private string[] nonTerminals;
+        private State[] states;
+        private Rule[] rules;
+
+        /// <summary>
+        /// Initialization method to allow derived classes
+        /// to insert the rule list into this base class.
+        /// </summary>
+        /// <param name="rules">The array of Rule objects</param>
+        protected void InitRules( Rule[] rules ) { this.rules = rules; }
+
+        /// <summary>
+        /// Initialization method to allow derived classes to
+        /// insert the states table into this base class.
+        /// </summary>
+        /// <param name="states">The pre-initialized states table</param>
+        protected void InitStates( State[] states ) { this.states = states; }
+
+        /// <summary>
+        /// OBSOLETE FOR VERSION 1.4.0
+        /// </summary>
+        /// <param name="size"></param>
+        protected void InitStateTable( int size ) { states = new State[size]; }
+
+        /// <summary>
+        /// Initialization method to allow derived classes
+        /// to insert the special value for the error and EOF tokens.
+        /// </summary>
+        /// <param name="err">The error state ordinal</param>
+        /// <param name="end">The EOF stat ordinal</param>
+        protected void InitSpecialTokens( int err, int end ) {
+            errorToken = err;
+            endOfFileToken = end;
+        }
+
+        /// <summary>
+        /// Initialization method to allow derived classes to
+        /// insert the non-terminal symbol names into this base class.
+        /// </summary>
+        /// <param name="names">Non-terminal symbol names</param>
+        protected void InitNonTerminals( string[] names ) { nonTerminals = names; }
+
+        #region YYAbort, YYAccept etcetera.
+        [Serializable]
+        [SuppressMessage( "Microsoft.Design", "CA1064:ExceptionsShouldBePublic" )]
+        // Reason for FxCop message suppression -
+        // This exception cannot escape from the local context
+        private class AcceptException : Exception {
+            internal AcceptException() { }
+            protected AcceptException( SerializationInfo i, StreamingContext c ) : base( i, c ) { }
+        }
+        [Serializable]
+        [SuppressMessage( "Microsoft.Design", "CA1064:ExceptionsShouldBePublic" )]
+        // Reason for FxCop message suppression -
+        // This exception cannot escape from the local context
+        private class AbortException : Exception {
+            internal AbortException() { }
+            protected AbortException( SerializationInfo i, StreamingContext c ) : base( i, c ) { }
+        }
+        [Serializable]
+        [SuppressMessage( "Microsoft.Design", "CA1064:ExceptionsShouldBePublic" )]
+        // Reason for FxCop message suppression -
+        // This exception cannot escape from the local context
+        private class ErrorException : Exception {
+            internal ErrorException() { }
+            protected ErrorException( SerializationInfo i, StreamingContext c ) : base( i, c ) { }
+        }
+
+        // The following methods are only called from within
+        // a semantic action. The thrown exceptions can never
+        // propagate outside the ShiftReduceParser class in 
+        // which they are nested.
+
+        /// <summary>
+        /// Force parser to terminate, returning "true"
+        /// </summary>
+        protected static void YYAccept() { throw new AcceptException(); }
+
+        /// <summary>
+        /// Force parser to terminate, returning "false"
+        /// </summary>
+        protected static void YYAbort() { throw new AbortException(); }
+
+        /// <summary>
+        /// Force parser to terminate, returning
+        /// "false" if error recovery fails.
+        /// </summary>
+        protected static void YYError() { throw new ErrorException(); }
+
+        /// <summary>
+        /// Check if parser in error recovery state.
+        /// </summary>
+        protected bool YYRecovering { get { return recovering; } }
+        #endregion
+
+        /// <summary>
+        /// Abstract base method. ShiftReduceParser calls this
+        /// to initialize the base class data structures.  Concrete
+        /// parser classes must override this method.
+        /// </summary>
+        protected abstract void Initialize();
+
+        /// <summary>
+        /// Main entry point of the Shift-Reduce Parser.
+        /// </summary>
+        /// <returns>True if parse succeeds, else false for
+        /// unrecoverable errors</returns>
+        public bool Parse() {
+            Initialize();	// allow derived classes to instantiate rules, states and nonTerminals
+
+            NextToken = 0;
+            FsaState = states[0];
+
+            StateStack.Push( FsaState );
+            valueStack.Push( CurrentSemanticValue );
+            LocationStack.Push( CurrentLocationSpan );
+
+            while (true) {
+#if TRACE_ACTIONS
+                Console.Error.WriteLine("Entering state {0} ", FsaState.number);
+                DisplayStack();
+#endif
+                int action = FsaState.defaultAction;
+
+                if (FsaState.ParserTable != null) {
+                    if (NextToken == 0) {
+                        // We save the last token span, so that the location span
+                        // of production right hand sides that begin or end with a
+                        // nullable production will be correct.
+                        LastSpan = scanner.yylloc;
+                        NextToken = scanner.yylex();
+#if TRACE_ACTIONS
+                       Console.Error.WriteLine( "Reading: Next token is {0}", TerminalToString( NextToken ) );
+#endif
+                    }
+#if TRACE_ACTIONS
+                    else 
+                        Console.Error.WriteLine( "Next token is still {0}", TerminalToString( NextToken ) );
+#endif
+                    if (FsaState.ParserTable.ContainsKey( NextToken ))
+                        action = FsaState.ParserTable[NextToken];
+                }
+
+                if (action > 0)         // shift
+                {
+                    Shift( action );
+                }
+                else if (action < 0)   // reduce
+                {
+                    try {
+                        Reduce( -action );
+                        if (action == -1)	// accept
+                            return true;
+                    }
+                    catch (AbortException) {
+                            return false;
+                    }
+                    catch (AcceptException) {
+                        return true;
+                    }
+                    catch (ErrorException) {
+                        if (!ErrorRecovery())
+                            return false;
+                        else
+                            throw;  // Rethrow x, preserving information.
+                    }
+                }
+                else if (action == 0 && !ErrorRecovery()) // error
+                    return false;
+            }
+        }
+
+        private void Shift( int stateIndex ) {
+#if TRACE_ACTIONS
+				Console.Error.Write("Shifting token {0}, ", TerminalToString(NextToken));
+#endif
+            FsaState = states[stateIndex];
+
+            valueStack.Push( scanner.yylval );
+            StateStack.Push( FsaState );
+            LocationStack.Push( scanner.yylloc );
+
+            if (recovering) {
+                if (NextToken != errorToken)
+                    tokensSinceLastError++;
+
+                if (tokensSinceLastError > 5)
+                    recovering = false;
+            }
+
+            if (NextToken != endOfFileToken)
+                NextToken = 0;
+        }
+
+        private void Reduce( int ruleNumber ) {
+#if TRACE_ACTIONS
+				DisplayRule(ruleNumber);
+#endif
+            Rule rule = rules[ruleNumber];
+            int rhLen = rule.RightHandSide.Length;
+            //
+            //  Default actions for unit productions.
+            //
+            if (rhLen == 1) {
+                CurrentSemanticValue = valueStack.TopElement();   // Default action: $$ = $1;
+                CurrentLocationSpan = LocationStack.TopElement(); // Default action "@$ = @1;
+            }
+            else if (rhLen == 0) {
+                // Create a new blank value.
+                // Explicit semantic action may mutate this value
+                CurrentSemanticValue = default( TValue );
+                // The location span for an empty production will start with the
+                // beginning of the next lexeme, and end with the finish of the
+                // previous lexeme.  This gives the correct behaviour when this
+                // nonsense value is used in later Merge operations.
+                CurrentLocationSpan = (scanner.yylloc != null && LastSpan != null ?
+                    scanner.yylloc.Merge( LastSpan ) :
+                    default( TSpan ));
+            }
+            else {
+                // Default action: $$ = $1;
+                CurrentSemanticValue = valueStack[LocationStack.Depth - rhLen];
+                //  Default action "@$ = @1.Merge(@N)" for location info.
+                TSpan at1 = LocationStack[LocationStack.Depth - rhLen];
+                TSpan atN = LocationStack[LocationStack.Depth - 1];
+                CurrentLocationSpan =
+                    ((at1 != null && atN != null) ? at1.Merge( atN ) : default( TSpan ));
+            }
+
+            DoAction( ruleNumber );
+
+            for (int i = 0; i < rule.RightHandSide.Length; i++) {
+                StateStack.Pop();
+                valueStack.Pop();
+                LocationStack.Pop();
+            }
+            FsaState = StateStack.TopElement();
+
+            if (FsaState.Goto.ContainsKey( rule.LeftHandSide ))
+                FsaState = states[FsaState.Goto[rule.LeftHandSide]];
+
+            StateStack.Push( FsaState );
+            valueStack.Push( CurrentSemanticValue );
+            LocationStack.Push( CurrentLocationSpan );
+        }
+
+        /// <summary>
+        /// Execute the selected action from array.
+        /// Must be overriden in derived classes.
+        /// </summary>
+        /// <param name="actionNumber">Index of the action to perform</param>
+        protected abstract void DoAction( int actionNumber );
+
+        private bool ErrorRecovery() {
+            bool discard;
+
+            if (!recovering) // if not recovering from previous error
+                ReportError();
+
+            if (!FindErrorRecoveryState())
+                return false;
+            //
+            //  The interim fix for the "looping in error recovery"
+            //  artifact involved moving the setting of the recovering 
+            //  bool until after invalid tokens have been discarded.
+            //
+            ShiftErrorToken();
+            discard = DiscardInvalidTokens();
+            recovering = true;
+            tokensSinceLastError = 0;
+            return discard;
+        }
+
+        private void ReportError() {
+            StringBuilder errorMsg = new StringBuilder();
+            errorMsg.AppendFormat( "Syntax error, unexpected {0}", TerminalToString( NextToken ) );
+
+            if (FsaState.ParserTable.Count < 7) {
+                bool first = true;
+                foreach (int terminal in FsaState.ParserTable.Keys) {
+                    if (first)
+                        errorMsg.Append( ", expecting " );
+                    else
+                        errorMsg.Append( ", or " );
+
+                    errorMsg.Append( TerminalToString( terminal ) );
+                    first = false;
+                }
+            }
+            scanner.yyerror( errorMsg.ToString() );
+        }
+
+        private void ShiftErrorToken() {
+            int old_next = NextToken;
+            NextToken = errorToken;
+
+            Shift( FsaState.ParserTable[NextToken] );
+
+#if TRACE_ACTIONS
+				Console.Error.WriteLine("Entering state {0} ", FsaState.number);
+#endif
+            NextToken = old_next;
+        }
+
+        private bool FindErrorRecoveryState() {
+            while (true)    // pop states until one found that accepts error token
+            {
+                if (FsaState.ParserTable != null &&
+                    FsaState.ParserTable.ContainsKey( errorToken ) &&
+                    FsaState.ParserTable[errorToken] > 0) // shift
+                    return true;
+
+#if TRACE_ACTIONS
+					Console.Error.WriteLine("Error: popping state {0}", StateStack.TopElement().number);
+#endif
+                StateStack.Pop();
+                valueStack.Pop();
+                LocationStack.Pop();
+
+#if TRACE_ACTIONS
+			    DisplayStack();
+#endif
+                if (StateStack.IsEmpty()) {
+#if TRACE_ACTIONS
+                        Console.Error.WriteLine("Aborting: didn't find a state that accepts error token");
+#endif
+                    return false;
+                }
+                else
+                    FsaState = StateStack.TopElement();
+            }
+        }
+
+        private bool DiscardInvalidTokens() {
+
+            int action = FsaState.defaultAction;
+
+            if (FsaState.ParserTable != null) {
+                // Discard tokens until find one that works ...
+                while (true) {
+                    if (NextToken == 0) {
+#if TRACE_ACTIONS
+                            Console.Error.Write("Reading a token: ");
+#endif
+                        NextToken = scanner.yylex();
+                    }
+#if TRACE_ACTIONS
+                        Console.Error.WriteLine("Next token is {0}", TerminalToString(NextToken));
+#endif
+                    if (NextToken == endOfFileToken)
+                        return false;
+
+                    if (FsaState.ParserTable.ContainsKey( NextToken ))
+                        action = FsaState.ParserTable[NextToken];
+
+                    if (action != 0)
+                        return true;
+                    else {
+#if TRACE_ACTIONS
+                            Console.Error.WriteLine("Error: Discarding {0}", TerminalToString(NextToken));
+#endif
+                        NextToken = 0;
+                    }
+                }
+            }
+            else if (recovering && tokensSinceLastError == 0) {
+                // 
+                //  Boolean recovering is not set until after the first
+                //  error token has been shifted.  Thus if we get back 
+                //  here with recovering set and no tokens read we are
+                //  looping on the same error recovery action.  This 
+                //  happens if current_state.ParserTable is null because
+                //  the state has an LR(0) reduction, but not all
+                //  lookahead tokens are valid.  This only occurs for
+                //  error productions that *end* on "error".
+                //
+                //  This action discards tokens one at a time until
+                //  the looping stops.  Another attack would be to always
+                //  use the LALR(1) table if a production ends on "error"
+                //
+#if TRACE_ACTIONS
+                    Console.Error.WriteLine("Error: panic discard of {0}", TerminalToString(NextToken));
+#endif
+                if (NextToken == endOfFileToken)
+                    return false;
+                NextToken = 0;
+                return true;
+            }
+            else
+                return true;
+        }
+
+        /// <summary>
+        /// Traditional YACC method.  Discards the next input token.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yyclearin" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yyclearin" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        protected void yyclearin() { NextToken = 0; }
+
+        /// <summary>
+        /// Tradional YACC method. Clear the "recovering" flag.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yyerrok" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yyerrok" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        protected void yyerrok() { recovering = false; }
+
+        /// <summary>
+        /// OBSOLETE FOR VERSION 1.4.0
+        /// Method used by derived types to insert new
+        /// state instances in the "states" array.
+        /// </summary>
+        /// <param name="stateNumber">index of the state</param>
+        /// <param name="state">data for the state</param>
+        protected void AddState( int stateNumber, State state ) {
+            states[stateNumber] = state;
+            state.number = stateNumber;
+        }
+
+        private void DisplayStack() {
+            Console.Error.Write( "State stack is now:" );
+            for (int i = 0; i < StateStack.Depth; i++)
+                Console.Error.Write( " {0}", StateStack[i].number );
+            Console.Error.WriteLine();
+        }
+
+        private void DisplayRule( int ruleNumber ) {
+            Console.Error.Write( "Reducing stack by rule {0}, ", ruleNumber );
+            DisplayProduction( rules[ruleNumber] );
+        }
+
+        private void DisplayProduction( Rule rule ) {
+            if (rule.RightHandSide.Length == 0)
+                Console.Error.Write( "/* empty */ " );
+            else
+                foreach (int symbol in rule.RightHandSide)
+                    Console.Error.Write( "{0} ", SymbolToString( symbol ) );
+
+            Console.Error.WriteLine( "-> {0}", SymbolToString( rule.LeftHandSide ) );
+        }
+
+        /// <summary>
+        /// Abstract state class naming terminal symbols.
+        /// This is overridden by derived classes with the
+        /// name (or alias) to be used in error messages.
+        /// </summary>
+        /// <param name="terminal">The terminal ordinal</param>
+        /// <returns></returns>
+        protected abstract string TerminalToString( int terminal );
+
+        private string SymbolToString( int symbol ) {
+            if (symbol < 0)
+                return nonTerminals[-symbol - 1];
+            else
+                return TerminalToString( symbol );
+        }
+
+        /// <summary>
+        /// Return text representation of argument character
+        /// </summary>
+        /// <param name="input">The character to convert</param>
+        /// <returns>String representation of the character</returns>
+        protected static string CharToString( char input ) {
+            switch (input) {
+                case '\a': return @"'\a'";
+                case '\b': return @"'\b'";
+                case '\f': return @"'\f'";
+                case '\n': return @"'\n'";
+                case '\r': return @"'\r'";
+                case '\t': return @"'\t'";
+                case '\v': return @"'\v'";
+                case '\0': return @"'\0'";
+                default: return string.Format( CultureInfo.InvariantCulture, "'{0}'", input );
+            }
+        }
+    }
+
+    /// <summary>
+    /// Classes implementing this interface must supply a
+    /// method that merges two location objects to return
+    /// a new object of the same type.
+    /// GPPG-generated parsers have the default location
+    /// action equivalent to "@$ = @1.Merge(@N);" where N
+    /// is the right-hand-side length of the production.
+    /// </summary>
+    /// <typeparam name="TSpan">The Location type</typeparam>
+#if EXPORT_GPPG
+    public interface IMerge<TSpan>
+#else
+    internal interface IMerge<TSpan>
+#endif
+ {
+        /// <summary>
+        /// Interface method that creates a location object from
+        /// the current and last object.  Typically used to create
+        /// a location object extending from the start of the @1
+        /// object to the end of the @N object.
+        /// </summary>
+        /// <param name="last">The lexically last object to merge</param>
+        /// <returns>The merged location object</returns>
+        TSpan Merge( TSpan last );
+    }
+
+    /// <summary>
+    /// This is the default class that carries location
+    /// information from the scanner to the parser.
+    /// If you don't declare "%YYLTYPE Foo" the parser
+    /// will expect to deal with this type.
+    /// </summary>
+#if EXPORT_GPPG
+    public class LexLocation : IMerge<LexLocation>
+#else
+    [SuppressMessage( "Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses" )]
+    internal class LexLocation : IMerge<LexLocation>
+#endif
+ {
+        private int startLine;   // start line
+        private int startColumn; // start column
+        private int endLine;     // end line
+        private int endColumn;   // end column
+
+        /// <summary>
+        /// The line at which the text span starts.
+        /// </summary>
+        public int StartLine { get { return startLine; } }
+
+        /// <summary>
+        /// The column at which the text span starts.
+        /// </summary>
+        public int StartColumn { get { return startColumn; } }
+
+        /// <summary>
+        /// The line on which the text span ends.
+        /// </summary>
+        public int EndLine { get { return endLine; } }
+
+        /// <summary>
+        /// The column of the first character
+        /// beyond the end of the text span.
+        /// </summary>
+        public int EndColumn { get { return endColumn; } }
+
+        /// <summary>
+        /// Default no-arg constructor.
+        /// </summary>
+        public LexLocation() { }
+
+        /// <summary>
+        /// Constructor for text-span with given start and end.
+        /// </summary>
+        /// <param name="sl">start line</param>
+        /// <param name="sc">start column</param>
+        /// <param name="el">end line </param>
+        /// <param name="ec">end column</param>
+        public LexLocation( int sl, int sc, int el, int ec ) { startLine = sl; startColumn = sc; endLine = el; endColumn = ec; }
+
+        /// <summary>
+        /// Create a text location which spans from the 
+        /// start of "this" to the end of the argument "last"
+        /// </summary>
+        /// <param name="last">The last location in the result span</param>
+        /// <returns>The merged span</returns>
+        public LexLocation Merge( LexLocation last ) { return new LexLocation( this.startLine, this.startColumn, last.endLine, last.endColumn ); }
+    }
+
+    /// <summary>
+    /// Abstract scanner class that GPPG expects its scanners to 
+    /// extend.
+    /// </summary>
+    /// <typeparam name="TValue">Semantic value type YYSTYPE</typeparam>
+    /// <typeparam name="TSpan">Source location type YYLTYPE</typeparam>
+#if EXPORT_GPPG
+    public abstract class AbstractScanner<TValue, TSpan>
+#else
+    internal abstract class AbstractScanner<TValue, TSpan>
+#endif
+ where TSpan : IMerge<TSpan> {
+        /// <summary>
+        /// Lexical value optionally set by the scanner. The value
+        /// is of the %YYSTYPE type declared in the parser spec.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Design", "CA1051:DoNotDeclareVisibleInstanceFields" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yylval" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yylval" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        // A field must be declared for this value of parametric type,
+        // since it may be instantiated by a value struct.  If it were 
+        // implemented as a property, machine generated code in derived
+        // types would not be able to select on the returned value.
+#pragma warning disable 649
+        public TValue yylval;                     // Lexical value: set by scanner
+#pragma warning restore 649
+
+        /// <summary>
+        /// Current scanner location property. The value is of the
+        /// type declared by %YYLTYPE in the parser specification.
+        /// </summary>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yylloc" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yylloc" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        public virtual TSpan yylloc {
+            get { return default( TSpan ); }       // Empty implementation allowing
+            set { /* skip */ }                   // yylloc to be ignored entirely.
+        }
+
+        /// <summary>
+        /// Main call point for LEX-like scanners.  Returns an int
+        /// corresponding to the token recognized by the scanner.
+        /// </summary>
+        /// <returns>An int corresponding to the token</returns>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yylex" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yylex" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        public abstract int yylex();
+
+        /// <summary>
+        /// Traditional error reporting provided by LEX-like scanners
+        /// to their YACC-like clients.
+        /// </summary>
+        /// <param name="format">Message format string</param>
+        /// <param name="args">Optional array of args</param>
+        [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "yyerror" )]
+        [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "yyerror" )]
+        // Reason for FxCop message suppression -
+        // This is a traditional name for YACC-like functionality
+        public virtual void yyerror( string format, params object[] args ) { }
+    }
+
+    /// <summary>
+    /// Encapsulated state for the parser.
+    /// Opaque to users, visible to the tool-generated code.
+    /// </summary>
+#if EXPORT_GPPG
+    public class State
+    {
+        /// <summary>
+        /// The number of states in the automaton.
+        /// </summary>
+        public int number;
+#else
+    internal class State {
+        /// <summary>
+        /// The index of this state in the states array.
+        /// </summary>
+        internal int number;
+#endif
+        internal Dictionary<int, int> ParserTable;   // Terminal -> ParseAction
+        internal Dictionary<int, int> Goto;          // NonTerminal -> State;
+        internal int defaultAction; // = 0;		     // ParseAction
+
+        /// <summary>
+        /// State transition data for this state. Pairs of elements of the 
+        /// goto array associate symbol ordinals with next state indices.
+        /// The actions array is passed to another constructor. 
+        /// </summary>
+        /// <param name="actions">The action list</param>c
+        /// <param name="goToList">Next state data</param>
+        public State( int[] actions, int[] goToList )
+            : this( actions ) {
+            Goto = new Dictionary<int, int>();
+            for (int i = 0; i < goToList.Length; i += 2)
+                Goto.Add( goToList[i], goToList[i + 1] );
+        }
+
+        /// <summary>
+        /// Action data for this state. Pairs of elements of the 
+        /// action array associate action ordinals with each of
+        /// those symbols that have actions in the current state.
+        /// </summary>
+        /// <param name="actions">The action array</param>
+        public State( int[] actions ) {
+            ParserTable = new Dictionary<int, int>();
+            for (int i = 0; i < actions.Length; i += 2)
+                ParserTable.Add( actions[i], actions[i + 1] );
+        }
+
+        /// <summary>
+        /// Set the default action for this state.
+        /// </summary>
+        /// <param name="defaultAction">Ordinal of the default action</param>
+        public State( int defaultAction ) {
+            this.defaultAction = defaultAction;
+        }
+
+        /// <summary>
+        /// Set the default action and the state transition table.
+        /// </summary>
+        /// <param name="defaultAction">The default action</param>
+        /// <param name="goToList">Transitions from this state</param>
+        public State( int defaultAction, int[] goToList )
+            : this( defaultAction ) {
+            Goto = new Dictionary<int, int>();
+            for (int i = 0; i < goToList.Length; i += 2)
+                Goto.Add( goToList[i], goToList[i + 1] );
+        }
+    }
+
+    /// <summary>
+    /// Rule representation at runtime.
+    /// </summary>
+#if EXPORT_GPPG
+    public class Rule
+#else
+    internal class Rule
+#endif
+ {
+        internal int LeftHandSide; // symbol
+        internal int[] RightHandSide; // symbols
+
+        /// <summary>
+        /// Rule constructor.  This holds the ordinal of
+        /// the left hand side symbol, and the list of
+        /// right hand side symbols, in lexical order.
+        /// </summary>
+        /// <param name="left">The LHS non-terminal</param>
+        /// <param name="right">The RHS symbols, in lexical order</param>
+        public Rule( int left, int[] right ) {
+            this.LeftHandSide = left;
+            this.RightHandSide = right;
+        }
+    }
+
+    /// <summary>
+    /// Stack utility for the shift-reduce parser.
+    /// GPPG parsers have three instances:
+    /// (1) The parser state stack, T = QUT.Gppg.State,
+    /// (2) The semantic value stack, T = TValue,
+    /// (3) The location stack, T = TSpan.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+#if EXPORT_GPPG
+    public class PushdownPrefixState<T>
+#else
+    internal class PushdownPrefixState<T>
+#endif
+ {
+        //  Note that we cannot use the BCL Stack<T> class
+        //  here as derived types need to index into stacks.
+        //
+        private T[] array = new T[8];
+        private int tos = 0;
+
+        /// <summary>
+        /// Indexer for values of the stack below the top.
+        /// </summary>
+        /// <param name="index">index of the element, starting from the bottom</param>
+        /// <returns>the selected element</returns>
+        public T this[int index] { get { return array[index]; } }
+
+        /// <summary>
+        /// The current depth of the stack.
+        /// </summary>
+        public int Depth { get { return tos; } }
+
+        internal void Push( T value ) {
+            if (tos >= array.Length) {
+                T[] newarray = new T[array.Length * 2];
+                System.Array.Copy( array, newarray, tos );
+                array = newarray;
+            }
+            array[tos++] = value;
+        }
+
+        internal T Pop() {
+            T rslt = array[--tos];
+            array[tos] = default( T );
+            return rslt;
+        }
+
+        internal T TopElement() { return array[tos - 1]; }
+
+        internal bool IsEmpty() { return tos == 0; }
+    }
+}
+

src/DataStreamSuite/BooleanExpressions/Usings.cs

@@ -0,0 +1,4 @@
+global using System;
+global using System.Linq;
+global using System.Collections.Generic;
+global using System.Collections.Immutable;

src/DataStreamSuite/BooleanExpressions/src/BooleanExpressionEvaluator.cs

@@ -1,289 +0,0 @@
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.Text.RegularExpressions;
-
-namespace BCG
-{
-   public delegate bool BooleanEval(object arg1, 
-   object arg2, 
-   IDictionary bindings);
-
-   public class BooleanExpressionException : Exception
-   {
-      public BooleanExpressionException(string format, params object[] args)
-         : base(String.Format(format, args))
-      { }
-   }
-
-   public abstract class BooleanExpressionValue
-   {
-      public abstract object getValue(IDictionary bindings);
-   }
-
-   public class BooleanExpressionConstant : BooleanExpressionValue
-   {
-      public BooleanExpressionConstant(object o)
-      { myObj = o; }
-      public override object getValue(IDictionary bindings)
-      { return myObj; }
-      private object myObj;
-   }
-
-   public class BooleanExpressionVariable : BooleanExpressionValue
-   {
-      public BooleanExpressionVariable(string id)
-      { myId = id; }
-
-      public string getId()
-      { return myId; }
-
-      public override object getValue(IDictionary bindings)
-      { return bindings[myId]; }
-      private string myId;
-   }
-
-   public delegate object BEFunction(List<object> args);
-
-   public class BooleanExpressionFunction : BooleanExpressionValue
-   {
-      public BooleanExpressionFunction(string fn, ArrayList args)
-      {
-         myFunction = fn;
-         myArgs = args;
-      }
-
-      public string getId()
-      { return myFunction; }
-
-      public override object getValue(IDictionary bindings)
-      {
-         List<object> argValues = new List<object>();
-         if (myArgs != null)
-            foreach (object o in myArgs)
-               if (o is BooleanExpressionValue)
-                  argValues.Add(((BooleanExpressionValue)o).getValue(bindings));
-               else
-                  throw new Exception("Unknown arg value type: " + o.ToString());
-
-         string k = BooleanExpressionEvaluator.functionPrefix + myFunction;
-         if (bindings.Contains(k))
-            return ((BEFunction)(bindings[k]))(argValues);
-         else
-            throw new BooleanExpressionException("function {0} is not defined", myFunction);
-      }
-      
-      private string myFunction;
-      private ArrayList myArgs;
-   }
-
-   public class BooleanExpressionEvaluator
-   {
-      public const string functionPrefix = "function:";
-
-      public BooleanExpressionEvaluator (object arg1,
-         BooleanEval f)
-         : this (arg1, null, f) 
-      {}
-
-      public BooleanExpressionEvaluator (object arg1, 
-         object arg2, 
-         BooleanEval f)
-      {
-         myArg1 = arg1;
-         myArg2 = arg2;
-         myF = f;
-
-      }
-  
-      static BooleanExpressionEvaluator()
-      {
-         myNumberTypes = new Hashtable();
-	 
-         myNumberTypes[typeof(byte)] = true;
-	 myNumberTypes[typeof(sbyte)] = true;
-	 
-         myNumberTypes[typeof(short)] = true;
-	 myNumberTypes[typeof(ushort)] = true;
-	 
-         myNumberTypes[typeof(int)] = true;
-	 myNumberTypes[typeof(uint)] = true;
-
-	 myNumberTypes[typeof(long)] = true;
-	 myNumberTypes[typeof(ulong)] = true;
-
-         myNumberTypes[typeof(double)] = true;
-	 myNumberTypes[typeof(float)] = true;
-      }
-
-      public bool eval (IDictionary bindings)
-      {
-         return 
-            myF (myArg1, myArg2,bindings);
-      }
-
-
-      public static bool and (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            (arg1 as BooleanExpressionEvaluator).eval (bindings)
-            &&
-            (arg2 as BooleanExpressionEvaluator).eval (bindings);
-
-      }
-
-      public static bool or (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            (arg1 as BooleanExpressionEvaluator).eval (bindings)
-            ||
-            (arg2 as BooleanExpressionEvaluator).eval (bindings);
-
-      }
-
-      public static bool xor (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            (arg1 as BooleanExpressionEvaluator).eval (bindings)
-            !=
-            (arg2 as BooleanExpressionEvaluator).eval (bindings);
-
-      }
-
-      public static bool not (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            !(arg1 as BooleanExpressionEvaluator).eval (bindings);
-      }
-
-      public static bool booleanValue(object arg1, object arg2, IDictionary bindings)
-      {
-         return (bool)(arg1 as BooleanExpressionValue).getValue(bindings);
-      }
-
-      public static bool myIsConversionLegal(Type t1, Type t2)
-      {
-	return
-	  myNumberTypes.Contains(t1) &&
-	  myNumberTypes.Contains(t2);
-      }
-
-      public static bool smaller (object arg1, object arg2, IDictionary bindings)
-      {
-         object lobj = (arg1 as BooleanExpressionValue).getValue(bindings);
-         object robj = (arg2 as BooleanExpressionValue).getValue(bindings);
-         
-         try 
-         {
-            if (lobj is DBNull && robj is DBNull)
-               return false;
-      
-            // anything is bigger than DBNull
-            if (lobj is DBNull)
-               return true;
-
-            if (robj is DBNull)
-               return false;
-      
-            if (lobj is string)
-               lobj = ((string)lobj).Trim();
-
-            if (robj is string)
-               robj = ((string)robj).Trim();
-
-
-
-            if (!lobj.GetType().Equals(robj.GetType()))
-            {
-               if (myIsConversionLegal(lobj.GetType(), robj.GetType()))
-                  lobj = 
-                     Convert.ChangeType(lobj,robj.GetType());
-               else if (myIsConversionLegal(robj.GetType(), lobj.GetType()))
-                  robj = 
-                     Convert.ChangeType(robj,lobj.GetType());
-            }
-
-            IComparable ic = lobj as IComparable;
-            return ic.CompareTo(robj) < 0;
-         }
-         catch (Exception e)
-         {
-            //BlueEventLog.logEvent(String.Format("Comparison between {0} and {1} failed", 
-            //   lobj == null? "null" : lobj, robj == null? null : robj),BlueEventLevel.Warning);
-            //BlueEventLog.logEvent(e);
-            throw (e);
-         }
-      }
-
-      public static bool equal (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            !(smaller (arg1, arg2, bindings) )
-            &&
-            !(smaller (arg2, arg1, bindings));
-      }
-
-      public static bool greater (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            smaller (arg2,arg1, bindings);
-      }
-
-      public static bool smallerEqual (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            !greater(arg1, arg2, bindings);
-      }
-  
-      public static bool greaterEqual (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            !smaller (arg1, arg2, bindings);
-      }
-
-      public static bool different (object arg1, object arg2, IDictionary bindings)
-      {
-         return 
-            !equal (arg1, arg2, bindings);
-      }
-
-      public static bool matches (object arg1, object arg2, IDictionary bindings)
-      {
-         try 
-         {
-            object lobj = (arg1 as BooleanExpressionValue).getValue(bindings);
-            object robj = (arg2 as BooleanExpressionValue).getValue(bindings);
-
-            if (DBNull.Value.Equals(lobj) && (robj is string))
-               return false;
-            else if (lobj is string && robj is string)
-               return Regex.IsMatch((string) lobj, (string) robj);
-            else
-               throw new Exception(String.Format("Type mismatch, cannot string match {0} with {1}", 
-                  lobj.GetType().Name,
-                  robj.GetType().Name));
-         }
-         catch (Exception e)
-         {
-            //BlueEventLog.logEvent(string.Format ("Comparison between {0} and {1} failed", 
-            //   arg1 == null? "null" : arg1, arg2 == null? null : arg2));            
-            //BlueEventLog.logEvent(e);
-            throw (e);
-         }
-      }
-  
-      public object getOperand1()
-      {return myArg1;}
-
-      public object getOperand2()
-      {return myArg2;}
-
- 
-      private object myArg1;
-      private object myArg2;
-      private BooleanEval myF;
-
-      private static Hashtable myNumberTypes ;
-   }
-
-}

src/DataStreamSuite/BooleanExpressions/tests/BooleanExpressionsTests.cs

@@ -1,191 +0,0 @@
-using System;
-using System.Collections;
-using System.IO;
-using NUnit.Framework;
-using System.Diagnostics;
-using BCG.Evaluator.BooleanExpression;
-
-namespace BCG
-{
-   [TestFixture]
-   public class BooleanExpressionsTests
-   {
-      [Test]
-      public void testBooleanExpressions()
-      {
-         BCG.Evaluator.BooleanExpression.syntax parser =
-            new BCG.Evaluator.BooleanExpression.syntax();
-
-         BooleanProgram exp = (BooleanProgram)parser.Parse("a=12/12/1912 and 2 = null or b=2 and not c=1 and b > a");
-
-         Hashtable h = new Hashtable();
-         h["a"] = new DateTime(1912, 12, 12, 0, 0, 1);
-         h["b"] = 2;
-         h["c"] = 2;
-         h["d"] = new DateTime(1912, 12, 12, 0, 0, 2);
-
-         Assert.That(exp.eval.eval(h));
-
-         parser =
-            new BCG.Evaluator.BooleanExpression.syntax();
-
-         exp = (BooleanProgram)parser.Parse("a=1 and (b=2 or b=3)");
-
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 5;
-
-         Assert.That(!exp.eval.eval(h));
-
-         // comparisons
-
-         // >
-         exp = (BooleanProgram)parser.Parse("a>b");
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 5;
-
-         Assert.That(!exp.eval.eval(h));
-
-         h["a"] = 5;
-         h["b"] = 1;
-
-         Assert.That(exp.eval.eval(h));
-
-         h["a"] = 1;
-         h["b"] = 1;
-
-         Assert.That(!exp.eval.eval(h));
-
-         // <
-         exp = (BooleanProgram)parser.Parse("a<b");
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 5;
-
-         Assert.That(exp.eval.eval(h));
-
-         h["a"] = 5;
-         h["b"] = 1;
-
-         Assert.That(!exp.eval.eval(h));
-
-         h["a"] = 1;
-         h["b"] = 1;
-
-         Assert.That(!exp.eval.eval(h));
-
-
-         // =
-         exp = (BooleanProgram)parser.Parse("a=b");
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 5;
-
-         Assert.That(!exp.eval.eval(h));
-
-         h["a"] = 1;
-         h["b"] = 1;
-
-         Assert.That(exp.eval.eval(h));
-
-
-         // <=
-         exp = (BooleanProgram)parser.Parse("a<=b");
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 5;
-
-         Assert.That(exp.eval.eval(h));
-
-         h["a"] = 5;
-         h["b"] = 1;
-
-         Assert.That(!exp.eval.eval(h));
-
-         h["a"] = 1;
-         h["b"] = 1;
-
-         Assert.That(exp.eval.eval(h));
-
-         // >=
-         exp = (BooleanProgram)parser.Parse("a>=b");
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 5;
-
-         Assert.That(!exp.eval.eval(h));
-
-         h["a"] = 5;
-         h["b"] = 1;
-
-         Assert.That(exp.eval.eval(h));
-
-         h["a"] = 1;
-         h["b"] = 1;
-
-         Assert.That(exp.eval.eval(h));
-
-         // <>
-         exp = (BooleanProgram)parser.Parse("a<>b");
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 5;
-
-         Assert.That(exp.eval.eval(h));
-
-         h["a"] = 1;
-         h["b"] = 1;
-
-         Assert.That(!exp.eval.eval(h));
-
-         // ~= (matches)
-         exp = (BooleanProgram)parser.Parse("a~=b");
-         h = new Hashtable();
-         h["a"] = "test";
-         h["b"] = "test";
-
-         Assert.That(exp.eval.eval(h));
-
-         h = new Hashtable();
-         h["a"] = "test";
-         h["b"] = "te.*";
-
-         Assert.That(exp.eval.eval(h));
-
-         h = new Hashtable();
-         h["a"] = "test";
-         h["b"] = "ti.*";
-
-         Assert.That(!exp.eval.eval(h));
-
-         h["a"] = DBNull.Value;
-         h["b"] = "1";
-
-         Assert.That(!exp.eval.eval(h));
-
-
-         // mixing ints and doubles
-         exp = (BooleanProgram)parser.Parse("a=b");
-         h = new Hashtable();
-         h["a"] = 1.0;
-         h["b"] = 5;
-
-         Assert.That(!exp.eval.eval(h));
-
-         exp = (BooleanProgram)parser.Parse("a=b");
-         h = new Hashtable();
-         h["a"] = 1;
-         h["b"] = 1.0;
-
-         exp = (BooleanProgram)parser.Parse("a=b");
-         h = new Hashtable();
-         h["a"] = 1.1;
-         h["b"] = 1;
-
-         Assert.That(!exp.eval.eval(h));
-
-      }
-   }
-}
-

src/DataStreamSuite/BooleanExpressionsInterpreter/BooleanExpressionsInterpreter.cs

@@ -1,128 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Collections;
-
-using BCG.Evaluator.BooleanExpression;
-
-namespace BCG
-{
-   public class BooleanExpressionsInterpreter
-   {
-      public class ParseTree
-      {
-         public BooleanProgram prog;
-      }
-
-      BooleanExpressionEvaluator myEval;
-      Dictionary<string, FunctionDefinition> myBindings = new Dictionary<string, FunctionDefinition>();
-
-      private string _exp;
-      public BooleanExpressionsInterpreter(string exp, out ParseTree prog)
-      {
-         _exp = exp;
-         myInit(exp, out prog);
-      }
-
-      public BooleanExpressionsInterpreter(string exp)
-      {
-         ParseTree pt;
-         myInit(exp, out pt);
-      }
-
-      private void myInit(string exp, out ParseTree pt)
-      {
-         syntax parser = new syntax();
-         try
-         {
-            pt = new ParseTree();
-            BooleanProgram bp;
-            pt.prog = (BooleanProgram)parser.Parse(exp);
-            if (pt.prog == null)
-               throw new BooleanExpressionsInterpreterException("{0} is not a valid boolean expression", exp);
-            myExtractDefinitions(pt.prog.definitions, myBindings);
-            myEval = pt.prog.eval;
-         }
-         catch (Tools.CSToolsFatalException)
-         {
-            throw new BooleanExpressionsInterpreterException("{0} is not a valid boolean expression", exp);
-         }
-
-      }
-
-      private void myVisitNode(object node, Action<object> a)
-      {
-         a(node);
-         if (node is BooleanExpression)
-         {
-            BooleanExpression be = (BooleanExpression)node;
-            foreach (object child in be.kids)
-               myVisitNode(child, a);
-         }
-      }
-      public void walkParseStree(Action<object> a, ParseTree pt)
-      {
-         foreach (object node in pt.prog.kids)
-            myVisitNode(node, a);
-      }
-
-      public Dictionary<string, bool> getAllIdentifiers(ParseTree pt)
-      {
-         Dictionary<string, bool> bindings = new Dictionary<string, bool>();
-         Action<object> a = (o) =>
-         {
-            if (o is IdentifierValue)
-            {
-               BooleanExpressionValue bev = ((IdentifierValue)o).eval;
-               BooleanExpressionVariable bvar = (BooleanExpressionVariable)bev;
-               bindings[bvar.getId()] = true;
-            }
-            else if (o is FunctionValue)
-            {
-               BooleanExpressionValue bev = ((FunctionValue)o).eval;
-               BooleanExpressionFunction func = (BooleanExpressionFunction)bev;
-               bindings[func.getId()] = false;
-            }
-         };
-         walkParseStree(a, pt);
-         return bindings;
-      }
-      private void myExtractDefinitions(Definitions definitions,
-         Dictionary<string, FunctionDefinition> bindings)
-      {
-         if (definitions != null)
-         {
-            SingleDef d = definitions.def;
-            List<string> args = new List<string>();
-            myExtractArg(d.args, args);
-
-            bindings[functionPrefix + d.id] = new FunctionDefinition
-            { name = d.id, args = args, evaluator = d.eval };
-            myExtractDefinitions(definitions.next, bindings);
-         }
-      }
-
-      public int nDefinitions()
-      { return myBindings.Count; }
-
-      private void myExtractArg(DefArgList args, List<string> argList)
-      {
-         if (args != null && args.arg != null)
-         {
-            argList.Add(args.arg);
-            myExtractArg(args.rest, argList);
-         }
-      }
-
-      // there are repeated here so clients do not have to know about BooleanExpressionEvaluator
-      public static string functionPrefix = BooleanExpressionEvaluator.functionPrefix;
-      public delegate object Function(List<object> args);
-      public object makeCBWrapper(Function f)
-      { return new BEFunction((lst) => { return f(lst); }); }
-
-
-      public bool eval(IDictionary bindings)
-      { return myEval.eval(new EvaluationEnvironment(bindings, myBindings)); }
-   }
-}

src/DataStreamSuite/BooleanExpressionsInterpreter/BooleanExpressionsInterpreter.csproj

@@ -1,22 +0,0 @@
-<Project Sdk="Microsoft.NET.Sdk">
-
-  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
-
-  <ItemGroup>
-    <PackageReference Include="NUnit" Version="3.13.3" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <ProjectReference Include="..\BooleanExpressions\BooleanExpressions.csproj" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <Reference Include="Tools">
-      <HintPath>$(Externals)\bin\cstools\Tools.dll</HintPath>
-    </Reference>
-  </ItemGroup>
-
-</Project>

src/DataStreamSuite/BooleanExpressionsInterpreter/BooleanExpressionsInterpreterException.cs

@@ -1,14 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace BCG
-{
-   public class BooleanExpressionsInterpreterException : System.Exception
-   {
-      public BooleanExpressionsInterpreterException(string fmt, params object[] args)
-         : base(String.Format(fmt, args))
-      { }
-   }
-}

src/DataStreamSuite/BooleanExpressionsInterpreter/EvaluationEnvironment.cs

@@ -1,232 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Collections;
-using System.Linq;
-using System.Text;
-
-namespace BCG
-{
-   class EvaluationEnvironment : IDictionary
-   {
-      IDictionary myUserBindings;
-      Dictionary<string, FunctionDefinition> myDefinitions;
-      public EvaluationEnvironment(IDictionary userBindings, Dictionary<string, FunctionDefinition> definitions)
-      {
-         this.myUserBindings = userBindings;
-         this.myDefinitions = definitions;
-      }
-
-
-      class Override : IDictionary
-      {
-         public Override(IDictionary d1, IDictionary d2)
-         {
-            myPrimary = d1;
-            mySecondary = d2;
-         }
-         public bool Contains(object key)
-         {
-            return 
-               myPrimary.Contains(key)||
-               mySecondary.Contains(key);
-         }
-
-         public object this[object key]
-         {
-            get
-            {
-               if (myPrimary.Contains(key))
-                  return myPrimary[key];
-               else
-                  return mySecondary[key];
-            }
-            set
-            {
-               throw new NotImplementedException();
-            }
-         }
-
-         IDictionary myPrimary;
-         IDictionary mySecondary;
-
-         #region Useless IDictionary Members
-         public void Add(object key, object value)
-         {
-            throw new NotImplementedException();
-         }
-
-         public void Clear()
-         {
-            throw new NotImplementedException();
-         }
-
-         public IDictionaryEnumerator GetEnumerator()
-         {
-            throw new NotImplementedException();
-         }
-
-         public bool IsFixedSize
-         {
-            get { throw new NotImplementedException(); }
-         }
-
-         public bool IsReadOnly
-         {
-            get { throw new NotImplementedException(); }
-         }
-
-         public ICollection Keys
-         {
-            get { throw new NotImplementedException(); }
-         }
-
-         public void Remove(object key)
-         {
-            throw new NotImplementedException();
-         }
-
-         public ICollection Values
-         {
-            get { throw new NotImplementedException(); }
-         }
-
-         public void CopyTo(Array array, int index)
-         {
-            throw new NotImplementedException();
-         }
-
-         public int Count
-         {
-            get { throw new NotImplementedException(); }
-         }
-
-         public bool IsSynchronized
-         {
-            get { throw new NotImplementedException(); }
-         }
-
-         public object SyncRoot
-         {
-            get { throw new NotImplementedException(); }
-         }
-
-
-
-         IEnumerator IEnumerable.GetEnumerator()
-         {
-            throw new NotImplementedException();
-         }
-
-         #endregion
-      }
-
-
-      public bool Contains(object key)
-      {
-         if (myDefinitions.ContainsKey(key.ToString()))
-            return true;
-         else
-            return myUserBindings.Contains(key);
-      }
-      public object this[object key]
-      {
-         get
-         {
-            if (myDefinitions.ContainsKey(key.ToString()))
-            {
-               FunctionDefinition fd = myDefinitions[key.ToString()];
-               return new BEFunction((args) =>
-                  {
-                     if (args.Count != fd.args.Count)
-                        throw new BooleanExpressionsInterpreterException("Parameter count mismatch for {0}. Expected: {1} Got: {2}",
-                           fd.name, fd.args.Count, args.Count);
-                     else
-                     {
-                        Hashtable newBindings = new Hashtable();
-                        for (int i = 0; i < args.Count; i++)
-                           newBindings[fd.args[i]] = args[i];
-                        return fd.evaluator.eval(new EvaluationEnvironment(new Override(newBindings, myUserBindings), myDefinitions));
-                     }
-                  });
-
-            }
-            else
-               return myUserBindings[key];
-         }
-         set
-         {
-            throw new NotImplementedException();
-         }
-      }
-
-      #region Useless IDictionary Members
-      public void Add(object key, object value)
-      {
-         throw new NotImplementedException();
-      }
-
-      public void Clear()
-      {
-         throw new NotImplementedException();
-      }
-
-      public IDictionaryEnumerator GetEnumerator()
-      {
-         throw new NotImplementedException();
-      }
-
-      public bool IsFixedSize
-      {
-         get { throw new NotImplementedException(); }
-      }
-
-      public bool IsReadOnly
-      {
-         get { throw new NotImplementedException(); }
-      }
-
-      public ICollection Keys
-      {
-         get { throw new NotImplementedException(); }
-      }
-
-      public void Remove(object key)
-      {
-         throw new NotImplementedException();
-      }
-
-      public ICollection Values
-      {
-         get { throw new NotImplementedException(); }
-      }
-
-      public void CopyTo(Array array, int index)
-      {
-         throw new NotImplementedException();
-      }
-
-      public int Count
-      {
-         get { throw new NotImplementedException(); }
-      }
-
-      public bool IsSynchronized
-      {
-         get { throw new NotImplementedException(); }
-      }
-
-      public object SyncRoot
-      {
-         get { throw new NotImplementedException(); }
-      }
-
-
-
-      IEnumerator IEnumerable.GetEnumerator()
-      {
-         throw new NotImplementedException();
-      }
-
-      #endregion
-   }
-}

src/DataStreamSuite/BooleanExpressionsInterpreter/FunctionDefinition.cs

@@ -1,14 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace BCG
-{
-   class FunctionDefinition
-   {
-      public string name;
-      public List<string> args;
-      public BooleanExpressionEvaluator evaluator;
-   }
-}

src/DataStreamSuite/BooleanExpressionsInterpreter/tests/BooleanExpressionTests.cs

@@ -1,86 +0,0 @@
-using System;
-using System.Collections.Generic;
-using NUnit.Framework;
-using System.Diagnostics;
-
-namespace BCG
-{
-   [TestFixture]
-   public class BooleaExpressionTests
-   {
-      [Test]
-      public void baseTest()
-      {
-         var interp =
-               new BooleanExpressionsInterpreter("1=1");
-         Assert.IsTrue(interp.eval(new Dictionary<string, object>()));
-
-         interp = new BooleanExpressionsInterpreter(@"define a() { true } 
-                                                      define f() { a and b and c}
-                                                      define g(a,b,c) { a and b and c}
-                                                      true");
-         Assert.IsTrue(interp.eval(new Dictionary<string, object>()));
-
-         interp = new BooleanExpressionsInterpreter("id>0");
-         Assert.IsTrue(interp.eval(new Dictionary<string, object> { { "id", 1 } }));
-      }
-
-      [Test]
-      public void getAllIdentifiersWorks()
-      {
-         BooleanExpressionsInterpreter.ParseTree pt;
-         var interp =
-               new BooleanExpressionsInterpreter("a=12/12/1912 and 2 = null or b=2 and not c=1 and b > a and f(1,2) > y(2,3)",out pt);
-         Dictionary<string, bool> ids = interp.getAllIdentifiers(pt);
-         Assert.AreEqual(ids.Count, 5);
-         Assert.IsTrue(ids["a"]);
-         Assert.IsTrue(ids["b"]);
-         Assert.IsTrue(ids["c"]);
-         Assert.IsFalse(ids["f"]);
-         Assert.IsFalse(ids["y"]);
-      }
-
-      [Test]
-      public void parameterPassingWorks()
-      {
-         var interp = new BooleanExpressionsInterpreter(@"define inOrder(a,b,c) { a >= b and b >= c}
-                                                          inOrder(x,y,z)");
-
-         Assert.IsTrue(interp.eval(new Dictionary<string, object>{{"x",3},{"y",2},{"z",1}}));
-         Assert.IsFalse(interp.eval(new Dictionary<string, object> { { "x", 1 }, {"y", 2 }, {"z", 3} }));
-      }
-
-      [Test]
-      public void parametersHaveCorretScope()
-      {
-         var interp = new BooleanExpressionsInterpreter(@"define inOrder(z,y,x) { z >= y and y >= x}
-                                                          inOrder(x,y,z)");
-
-         Assert.IsTrue(interp.eval(new Dictionary<string, object> { { "x", 3 }, { "y", 2 }, { "z", 1 } }));
-         Assert.IsFalse(interp.eval(new Dictionary<string, object> { { "x", 1 }, { "y", 2 }, { "z", 3 } }));
-      }
-
-      [Test]
-      public void functionsCanCallOtherFunctions()
-      {
-         var interp = new BooleanExpressionsInterpreter(
-@"define ascending(x,y,z)   { x <= y and y <= z}
-  define descending(x,y,z)  { ascending(z,y,x)}
-  descending(x,y,z)");
-
-         Assert.IsTrue(interp.eval(new Dictionary<string, object> { { "x", 3 }, { "y", 2 }, { "z", 1 } }));
-         Assert.IsFalse(interp.eval(new Dictionary<string, object> { { "x", 1 }, { "y", 2 }, { "z", 3 } }));
-      }
-
-      [Test]
-      public void evaluationHasDynamicScope()
-      {
-         var interp = new BooleanExpressionsInterpreter(
-@"define isEquity(){ group='Equity'}
-  isEquity()");
-
-         Assert.IsTrue(interp.eval(new Dictionary<string, object> { { "group", "Equity" } }));
-         Assert.IsFalse(interp.eval(new Dictionary<string, object> { { "group", "NotEquity" } }));
-      }
-   }
-}

src/DataStreamSuite/Bts.DataStream.Websocket/Bts.DataStream.Websocket.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\client\spark_websocket\spark_websocket.csproj" />
+    <ProjectReference Include="..\DataStreamExpressions\DataStreamExpressions.csproj" />
+    <ProjectReference Include="..\..\client\spark_core\spark_core.csproj" />
+  </ItemGroup>
+
+</Project>

src/DataStreamSuite/Bts.DataStream.Websocket/ChatGptSession.cs

@@ -0,0 +1,54 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+
+using System;
+using System.Net.WebSockets;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+public class ChatGptSession {
+   public static Task Start() {
+      var host = new WebHostBuilder()
+         .UseKestrel()
+         .UseUrls("http://0.0.0.0:5000")
+         .UseStartup<ChatGptSession>()
+         .Build();
+      return host.RunAsync();
+   }
+
+   public void Configure(IApplicationBuilder app) {
+      app.UseWebSockets();
+      app.Use(async (context, next) => {
+         if (context.WebSockets.IsWebSocketRequest) {
+            WebSocket webSocket = await context.WebSockets.AcceptWebSocketAsync();
+
+            // Handle WebSocket connection
+            await HandleWebSocketConnection(webSocket);
+         } else {
+            await next();
+         }
+      });
+   }
+
+   async Task HandleWebSocketConnection(WebSocket webSocket) {
+      var buffer = new byte[1024];
+      WebSocketReceiveResult result;
+
+      while (webSocket.State == WebSocketState.Open) {
+         result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
+
+         if (result.MessageType == WebSocketMessageType.Text) {
+            var message = Encoding.UTF8.GetString(buffer, 0, result.Count);
+
+            // Echo the received message back to the client
+            await webSocket.SendAsync(new ArraySegment<byte>(Encoding.UTF8.GetBytes("Server: " + message)),
+                result.MessageType, result.EndOfMessage, CancellationToken.None);
+         } else if (result.MessageType == WebSocketMessageType.Close) {
+            // Close the WebSocket connection
+            await webSocket.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
+         }
+      }
+   }
+}

src/DataStreamSuite/Bts.DataStream.Websocket/ClientSubscription.cs

@@ -0,0 +1,9 @@
+namespace Bts.DataStream.Websocket;
+
+class ClientSubscription(WebsocketClientID id, SubscriptionParams @params, IDisposable dispose) : IDisposable {
+   public SubscriptionParams Params => @params;
+   public WebsocketClientID Id => id;
+
+   public void Dispose() =>
+      dispose.Dispose();
+}

src/DataStreamSuite/Bts.DataStream.Websocket/DataSync.cs

@@ -0,0 +1,229 @@
+namespace Bts.DataStream.Websocket;
+
+using BCG;
+
+using bts;
+using bts.api.core;
+using bts.collections;
+
+using Bts.DataStreamExpressions;
+using Bts.Websocket;
+
+using mbts.utils;
+
+using Spark.Core.Disposables;
+
+using System.Reactive.Subjects;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+/// <summary>
+/// Represents an I/O model (<see cref="ISubject{TSource, TResult}"/>), that accepts websocket
+/// requests (from clients) as input, and emits data/notifications (to clients) as output.
+/// This class's chief role is managing data subscriptions to sparkd on the clients' behalf.
+/// </summary>
+public class DataSync(ServiceContext serviceCtx, JsonSerializerOptions? serializerOpts = null) :
+   ISubject<WebsocketConnectionUpdate, IEnumerable<WebsocketOutgoingMessage>> {
+   readonly ServiceContext serviceCtx = serviceCtx;
+   readonly JsonSerializerOptions serializerOpts = serializerOpts ?? JsonSerializerOptions.Default;
+   readonly Dictionary<WebsocketClientID, List<ClientSubscription>> clients = [];
+   readonly object lockObj = new();
+
+   event Action<IEnumerable<WebsocketOutgoingMessage>>? requestSend;
+
+   public void OnCompleted() =>
+      Log.Api.info("DataSync incoming request stream has completed.");
+
+   public void OnError(Exception error) =>
+      Log.Api.error($"DataSync error: {error}");
+
+   public void OnNext(WebsocketConnectionUpdate value) {
+      switch (value.Type) {
+         case WebsocketConnectionUpdateType.IncomingMessage:
+            onIncomingMessage(value.IncomingMessage);
+            break;
+         case WebsocketConnectionUpdateType.Connect:
+            onConnect(value.Connect);
+            break;
+         case WebsocketConnectionUpdateType.Disconnect:
+            onDisconnect(value.Disconnect);
+            break;
+         default:
+            Log.assert(false, $"Unexpected WebsocketConnectionUpdate type: {value.Type}");
+            break;
+      }
+   }
+
+   public IDisposable Subscribe(IObserver<IEnumerable<WebsocketOutgoingMessage>> observer) {
+      lock (lockObj) {
+         requestSend += observer.OnNext;
+         return Disposable.Create(dispose);
+      }
+      void dispose() {
+         lock (lockObj) {
+            requestSend -= observer.OnNext;
+         }
+      }
+   }
+
+   static JsonRpcId? extractRpcId(string messageBody) {
+      try {
+         return JsonNode.Parse(messageBody)
+            ?.AsObject()
+            ?.GetValueOrDefault("id")
+            ?.Deserialize<JsonRpcId>();
+      } catch {
+         return null;
+      }
+   }
+
+   void onConnect(WebsocketConnectNotification notification) {
+      var id = notification.Id;
+      lock (lockObj) {
+         clients.Add(id, new());
+      }
+      Log.Api.info($"DataStreamWebsocketDataSync client connected. clientId: {notification.Id}");
+      if (notification.Message is not null) {
+         onIncomingMessage(notification.Message);
+      }
+   }
+
+   void onDisconnect(WebsocketDisconnectNotification notification) {
+      Log.Api.warn($"DataStreamWebsocketDataSync client disconnected. clientId: {notification.Id}");
+      unsubscribeAll(notification.Id);
+      clients.Remove(notification.Id);
+   }
+
+   void onIncomingMessage(WebsocketIncomingMessage message) {
+      var id = message.sender_client_id;
+      if (!JsonRpcRequest.TryDeserialize(message, out var req, out var err)) {
+         onBadRequest(message, err);
+         return;
+      }
+      switch (req.Method!.ToLower()) {
+         case "subscribe":
+            subscribe(id, req);
+            break;
+         case "unsubscribe":
+            unsubscribe(id, req);
+            break;
+         case "unsubscribe_all":
+            unsubscribeAll(id);
+            break;
+         default:
+            Log.Api.error($"Received request of unknown type: {req}");
+            break;
+      }
+   }
+
+   void sendNotification<T>(WebsocketClientID id, string method, T rpcParams) {
+      var rpcNotification = JsonRpcRequest.CreateNotification(method, rpcParams);
+      var rpcNotificationStr = JsonSerializer.Serialize(rpcNotification, serializerOpts);
+      send(new WebsocketOutgoingMessage[] { new(id, rpcNotificationStr) });
+   }
+
+   void sendResponse<T>(WebsocketClientID id, JsonRpcId rpcId, T rpcParams) {
+      var rpcRes = JsonRpcResponse.Create(rpcId, rpcParams);
+      var rpcResStr = JsonSerializer.Serialize(rpcRes, serializerOpts);
+      send(new WebsocketOutgoingMessage[] { new(id, rpcResStr )});
+   }
+
+   void sendError<T>(WebsocketClientID id, JsonRpcId rpcId, JsonRpcError<T> error) {
+      var rpcRes = JsonRpcResponse.CreateError(rpcId, error);
+      var rpcResStr = JsonSerializer.Serialize(rpcRes, serializerOpts);
+      send(new WebsocketOutgoingMessage[] { new(id, rpcResStr) });
+   }
+
+   bool send(IEnumerable<WebsocketOutgoingMessage> messages) {
+      lock (lockObj) {
+         if (requestSend is null) {
+            Log.Api.warn(
+               $"Unable to send message(s) because '{nameof(requestSend)}' handler is null");
+            return false;
+         }
+         requestSend(messages);
+         return true;
+      }
+   }
+
+   void subscribe(WebsocketClientID id, JsonRpcRequest<JsonObject?> req) {
+      var subParams = req.Params!.Deserialize<SubscriptionParams>()!;
+      var exp = DataStreamExpressionsInterpreter.Evaluate(subParams.Query!);
+      var stream = exp.getView(new Dictionary<string, StatementExpression>(0));
+      var sub = new ClientSubscription(id, subParams, Disposable.Create(dispose));
+      lock (lockObj) {
+         clients[id].Add(sub);
+         sendResponse(id, req.Id!.Value, req.Params);
+         stream.onChange += onChange;
+      }
+
+      void onChange(object? newValue) {
+         var dp = ExceptionAssert.of_type<DataPacket>(newValue);
+         var rpcParams = new {
+            addedRows = dp.addedRows,
+            deletedRows = dp.deletedRows
+         };
+         sendNotification(id, "subscription", rpcParams);
+      }
+
+      void dispose() =>
+         stream.onChange -= onChange;
+   }
+
+   void unsubscribe(WebsocketClientID id, JsonRpcRequest<JsonObject?> req) {
+      var subParams = req.Params!.Deserialize<SubscriptionParams>();
+      var subParamsStr = JsonSerializer.Serialize(subParams, serializerOpts);
+      // Minimize amount of code inside lock (just need it to find/remove the subscription)
+      List<ClientSubscription>? subs = null;
+      ClientSubscription? sub = null;
+      lock (lockObj) {
+         subs = clients.GetValueOrDefault(id);
+         subs?.TryRemoveFirst(s => s!.Params.Equals(subParams), out sub);
+      }
+      if (subs is null) {
+         // Didn't find client (log/throw).
+         var msg = $"Unable to unsubscribe: did not find client. Id: {id}.\nParams:\n{subParamsStr}";
+         Log.Api.error(msg);
+         throw new Exception(msg);
+      }
+      if (sub is null) {
+         // Found client, but didn't find subscription (log/throw).
+         var msg = $"Unable to unsubscribe: did not find the specified subscription. " +
+            $"Id: {id}. Request:\n{subParams}";
+         Log.Api.error(msg);
+         throw new Exception(msg);
+      }
+      // Found client and subscription (dispose/remove subscription).
+      Log.Api.info($"Unsubscribing client. Id: {id}.\nParams:\n{subParamsStr}");
+      sub.Dispose();
+   }
+
+   void unsubscribeAll(WebsocketClientID id) {
+      lock (lockObj) {
+         if (!clients.TryGetValue(id, out var subs)) {
+            throw new Exception(
+               $"Unable to unsubscribe: did not find client with id {id}");
+         }
+         subs.DisposeAll();
+         subs.Clear();
+      }
+   }
+
+   void onBadRequest(WebsocketIncomingMessage req, string? errorMsg) {
+      var rpcId = extractRpcId(req.message_body);
+      var logMsg = $"Recieved invalid request:\n{req.message_body}";
+      if (errorMsg is not null) {
+         logMsg += $"\n\n**Exception**\n{errorMsg}";
+      }
+      Log.Api.error(logMsg);
+      if (rpcId is null) {
+         return;
+      }
+      // Send error back to client
+      var rpcErr = JsonRpcError.Create(
+         (long)JsonRpcErrorCode.InvalidRequest,
+         $"Received invalid request: {errorMsg ?? "unknown error"}",
+         req.message_body);
+      sendError(req.sender_client_id, rpcId.Value, rpcErr);
+   }
+}

src/DataStreamSuite/Bts.DataStream.Websocket/JObjectExtensions.cs

@@ -0,0 +1,34 @@
+namespace Bts.DataStream.Websocket;
+
+using Newtonsoft.Json.Linq;
+
+using System.Diagnostics.CodeAnalysis;
+
+public static class JObjectExtensions {
+   public static bool TryParse<T>(
+      this JObject filter, string key, [MaybeNull] out T obj, [NotNullWhen(false)] out string? error) {
+      obj = default;
+      var value = filter.GetValueOrDefault(key)?.ToString();
+      if (value == null) {
+         error = $"{key} not present";
+         return true;
+      }
+      return WebsocketJsonParsers.TryParse(value, key, out obj, out error);
+   }
+
+   public static bool TryParse<T>(
+     this JObject filter, string key, out T result, [NotNullWhen(false)] out string? error, T defaultValue) {
+      var value = filter.GetValueOrDefault(key)?.ToString();
+      if (value == null) {
+         result = defaultValue;
+         error = $"{key} not present";
+         return true;
+      }
+      if (WebsocketJsonParsers.TryParse<T>(value, key, out var maybeRes, out error)) {
+         result = maybeRes ?? defaultValue;
+         return true;
+      }
+      result = defaultValue;
+      return false;
+   }
+}

src/DataStreamSuite/Bts.DataStream.Websocket/JsonParseResult.cs

@@ -0,0 +1,24 @@
+namespace Bts.DataStream.Websocket;
+
+using Newtonsoft.Json.Linq;
+
+class JsonParseResult {
+   public string? MessageId { get; init; }
+   public RequestType Type { get; init; }
+   public JObject? Parameters { get; init; }
+   public string? Error { get; init; }
+   public bool Successful => Error is not null;
+
+   public static JsonParseResult CreateError(string error) =>
+      new() {
+         Error = error,
+         MessageId = "missing"
+      };
+
+   public static JsonParseResult Create(string messageId, RequestType type, JObject parameters) =>
+      new() {
+         MessageId = messageId,
+         Parameters = parameters,
+         Type = type
+      };
+}

src/DataStreamSuite/Bts.DataStream.Websocket/JsonRpcErrorCode.cs

@@ -0,0 +1,6 @@
+namespace Bts.DataStream.Websocket;
+
+public enum JsonRpcErrorCode {
+   None = 0,
+   InvalidRequest = 1,
+}

src/DataStreamSuite/Bts.DataStream.Websocket/MultilineStringJsonConverter.cs

@@ -0,0 +1,48 @@
+namespace Bts.DataStream.Websocket;
+
+using Spark.Core;
+
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+class MultilineStringJsonConverter : JsonConverter<string> {
+   public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+      if (typeToConvert != typeof(string)) {
+         throw new ArgumentException($"Unable to parse {typeToConvert}", nameof(typeToConvert));
+      }
+      return reader.TokenType switch {
+         JsonTokenType.String => stringImpl(ref reader),
+         JsonTokenType.StartArray => arrayImpl(ref reader),
+         _ => throw new ArgumentException(
+            $"Unable to parse {typeof(SubscriptionParams)} from {reader.TokenType}"),
+      };
+
+      static string? stringImpl(ref Utf8JsonReader reader) =>
+         new(reader.GetString()!);
+
+      static string? arrayImpl(ref Utf8JsonReader reader) {
+         var lines = new List<string>(2);
+         while (reader.Read()) {
+            switch (reader.TokenType) {
+               case JsonTokenType.String:
+                  lines.Add(reader.GetString()!);
+                  break;
+               case JsonTokenType.EndArray:
+                  return string.Join("\n", lines);
+            }
+         }
+         throw new JsonException(
+            $"Failed to parse {typeof(SubscriptionParams)} (did not reach end of array)");
+      }
+   }
+
+   public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options) {
+      var lines = value.Split("\n");
+      if (lines.Length < 2) {
+         writer.WriteRawValue(value);
+         return;
+      }
+      writer.WriteRawValue($"[{", ".join(lines)}]");
+   }
+}

src/DataStreamSuite/Bts.DataStream.Websocket/RequestType.cs

@@ -0,0 +1,8 @@
+namespace Bts.DataStream.Websocket;
+
+public enum RequestType {
+   Unspecified,
+   Subscribe,
+   Unsubscribe,
+   UnsubscribeAll,
+}

src/DataStreamSuite/Bts.DataStream.Websocket/Session.cs

@@ -0,0 +1,27 @@
+namespace Bts.DataStream.Websocket;
+
+using bts;
+using bts.api.core;
+
+using Bts.Websocket;
+
+using Google.Protobuf;
+
+using System.Text.Json;
+
+public static class Session {
+   static int sessionIdCounter;
+
+   public static async Task Start(
+      ServiceContext context, WebsocketServerConfig config, JsonSerializerOptions? opts) {
+      opts ??= JsonSerializerOptions.Default;
+      var sessionId = Interlocked.Increment(ref sessionIdCounter);
+      var gateway = new WebsocketGatewayObservable(config);
+      var sync = new DataSync(context, opts);
+      using var syncSub = gateway.Subscribe(sync);
+      using var gwSub = sync.Subscribe(gateway);
+      Log.Api.info($"Starting DataStream Websocket Session {sessionId}");
+      Log.Api.info($"DataStream Websocket Session {sessionId} config:\n{JsonFormatter.Default.Format(config)}");
+      await gateway.ConnectAsync();
+   }
+}

src/DataStreamSuite/Bts.DataStream.Websocket/SubscriptionParams.cs

@@ -0,0 +1,110 @@
+namespace Bts.DataStream.Websocket;
+
+using Spark.Core;
+
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+public class SubscriptionParams : IEquatable<SubscriptionParams> {
+   static class PropNames {
+      public const string QUERY = "query";
+   }
+
+   public SubscriptionParams(string? query) {
+      Query = query;
+   }
+
+   // Serializer supports plain string, or an array of lines for convenience
+   [MaybeNull]
+   [JsonPropertyName(PropNames.QUERY)]
+   [JsonConverter(typeof(MultilineStringJsonConverter))]
+   public string? Query { get; set; }
+
+   public bool Equals(SubscriptionParams? other) =>
+      other is not null &&
+      Query == other.Query;
+
+   class SubscriptionParamsConverter : JsonConverter<SubscriptionParams> {
+      public override bool CanConvert(Type typeToConvert) =>
+         typeToConvert == typeof(SubscriptionParams);
+
+      public override SubscriptionParams Read(
+         ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+         if (typeToConvert != typeof(SubscriptionParams)) {
+            throw new ArgumentException($"Unable to parse {typeToConvert}", nameof(typeToConvert));
+         }
+         return read(ref reader);
+      }
+
+      SubscriptionParams read(ref Utf8JsonReader reader) {
+         return reader.TokenType switch {
+            JsonTokenType.String => stringImpl(ref reader),
+            JsonTokenType.StartArray => arrayImpl(ref reader),
+            JsonTokenType.StartObject => objectImpl(ref reader),
+            _ => throw new ArgumentException(
+               $"Unable to parse {typeof(SubscriptionParams)} from {reader.TokenType}"),
+         };
+
+         static SubscriptionParams stringImpl(ref Utf8JsonReader reader) =>
+            new(reader.GetString()!);
+
+         static SubscriptionParams arrayImpl(ref Utf8JsonReader reader) {
+            var lines = new List<string>(2);
+            while (reader.Read()) {
+               switch (reader.TokenType) {
+                  case JsonTokenType.String:
+                     lines.Add(reader.GetString()!);
+                     break;
+                  case JsonTokenType.EndArray:
+                     return new("\n".join(lines));
+               }
+            }
+            throw new JsonException(
+               $"Failed to parse {typeof(SubscriptionParams)} (did not reach end of array)");
+         }
+
+         static SubscriptionParams objectImpl(ref Utf8JsonReader reader) {
+            var lines = new List<string>(2);
+            while (reader.Read()) {
+               switch (reader.TokenType) {
+                  case JsonTokenType.PropertyName:
+                     var propName = reader.GetString()!;
+                     if (propName == PropNames.QUERY) {
+                        switch (reader.TokenType) {
+                           case JsonTokenType.StartArray:
+                              return arrayImpl(ref reader);
+                           case JsonTokenType.String:
+                              return stringImpl(ref reader);
+                        }
+                     }
+                     break;
+                  case JsonTokenType.String:
+                     lines.Add(reader.GetString()!);
+                     break;
+                  case JsonTokenType.EndArray:
+                     return new("\n".join(lines));
+               }
+            }
+            throw new JsonException(
+               $"Failed to parse {typeof(SubscriptionParams)} (did not reach end of array)");
+         }
+      }
+
+      public override void Write(
+         Utf8JsonWriter writer, SubscriptionParams value, JsonSerializerOptions options) {
+         var q = value.Query;
+         var lines = q?.Split("\n");
+         if (lines is null || lines.Length < 2) {
+            writer.WriteString(PropNames.QUERY, value.Query);
+            return;
+         }
+         writer.WriteStartArray(PropNames.QUERY);
+         foreach (var l in lines) {
+            writer.WriteStringValue(l);
+         }
+         writer.WriteEndArray();
+      }
+   }
+}

src/DataStreamSuite/Bts.DataStream.Websocket/Usings.cs

@@ -0,0 +1,5 @@
+global using bts.websocket_core;
+
+global using System;
+
+global using System.Collections.Immutable;