pauldeen79.ExpressionFramework.Parser 0.7.4

ExpressionFramework

Evaluates expressions.

Example:

var expression = new FieldExpression("Name");
var context = new { Name = "Hello world!" };
var result = expression.Evaluate(context).Value;
// generates: Hello world!

See unit tests for more examples.

Code generation

I am currently not storing generated files in the code repository. To generate, simply run the console project from either Visual Studio (hit F5) or a command prompt. This will replace almost all generated code.

There are some files (evaluatables, expressions, operators and aggregators) being generated for the first time only. This is known as code scaffolding, which happens when you add a new evaluatable, expression, operator or aggregator type.

Code generation

I am currently not storing generated files in the code repository. To generate, you have to trigger the code generation tool from either Visual Studio (hit F5) or a command prompt. This will replace all generated code.

I am using t4plus, which is a dotnet global tool, so it can run on all environments. The models and code generation are stored in an assembly which is also added to the solution. Note that there is no project reference to this project, it is only needed at build time.

At this moment, I am not using automatic code generation after changing code generation models or providers. This can be enabled, but is a bit cumbersome in build pipelines. First, the file system isn't updated fast enough, so the build will not succeed on a fresh cloned instance. Second, Sonar runs the post build command in a Docker image, and this image doesn't know how to load the code generation tool. Because of these problems, I have commented the post build event. You may uncomment it if you find yourself constantly re-generating stuff.

Command to install t4plus:

dotnet tool install --global pauldeen79.TextTemplateTransformationFramework.T4.Plus.Cmd --version 0.2.5

Command to build code generation project (example where you are in the root directory):

dotnet build -c Debug src/ExpressionFramework.CodeGeneration/ExpressionFramework.CodeGeneration.csproj

Command to run code generation (example where you are in the root directory):

Invoke-Expression "t4plus assembly -a $(Resolve-Path "src/ExpressionFramework.CodeGeneration/bin/Debug/net7.0/ExpressionFramework.CodeGeneration.dll") -p $(Resolve-Path "src") -u $(Resolve-Path "src/ExpressionFramework.CodeGeneration/bin/Debug/net7.0")"

Note that the -a argument of the t4plus assembly command currently requires a fully qualified path to the code generation assembly.

You can use the following post build event in the code generation project to run it automatically after changing code generation models or providers:

<Target Name="PostBuild" AfterTargets="PostBuildEvent">
  <Exec Command="t4plus assembly -a $(TargetDir)ExpressionFramework.CodeGeneration.dll -p $(TargetDir)../../../../ -u $(TargetDir)" />
</Target>

Note that if you use a post build event, this will cause SonarCloud to fail because t4plus is not available in the docker image where the code analysis runs. To fix this, you need the following PowerShell script:

((Get-Content -path src/ExpressionFramework.CodeGeneration/ExpressionFramework.CodeGeneration.csproj -Raw) -replace 't4plus','echo') | Set-Content -Path src/ExpressionFramework.CodeGeneration/ExpressionFramework.CodeGeneration.csproj