Scripting API Samples

Tomáš Matoušek edited this page on Jan 31 ·

Pages 43

• Contributors

  Tool Authors

  Status

  .NET Core

  Interactive and Scripting

  Clone this wiki locally

  

  The scripting APIs enable .NET applications to instatiate a C# engine and execute code snippets against host-supplied objects. Below are examples of how to get started with the scripting APIs and some common samples. You can also view the Scripting API .

  Supported Platforms

  Scripting APIs require desktop .NET Framework 4.6+, or .NET Core 1.1 (supported since , Visual Studio 2017 RC3).

  Scripting APIs can't be used within Universal Windows Applications and .NET Native since the application model doesn't support loading code generated at runtime.

  Getting Started

  Install the :

  Install-Package Microsoft.CodeAnalysis.CSharp.Scripting

  Code Samples

  Note: the samples require the following using:

  using Microsoft.CodeAnalysis.CSharp.Scripting;

  Scenarios

  

  Evaluate a C# expression

  object result = await CSharpScript.EvaluateAsync("1 + 2");

  Evaluate a C# expression (strongly-typed)

  int result = await CSharpScript.EvaluateAsync<int>("1 + 2");

  Evaluate a C# expression with error handling

  try

  {

  Console.WriteLine(await CSharpScript.EvaluateAsync("2+2"));

  }

  catch (CompilationErrorException e)

  {

  Console.WriteLine(string.Join(Environment.NewLine, e.Diagnostics));

  }

  Add references

  var result = await CSharpScript.EvaluateAsync("System.Net.Dns.GetHostName()",

  ScriptOptions.Default.WithReferences(typeof(System.Net.Dns).Assembly));

  Add imports

  var result = await CSharpScript.EvaluateAsync("Sqrt(2)",

  ScriptOptions.Default.WithImports("System.Math"));

  Parameterize a script

  public class Globals

  {

  public int X;

  public int Y;

  }

  var globals = new Globals { X = 1, Y = 2 };

  Console.WriteLine(await CSharpScript.EvaluateAsync<int>("X+Y", globals: globals));

  Note: Currently the Globals type has to be defined in an assembly loaded from a file. If the assembly is in-memory (including e.g. when the sample is executed in Interactive Window) the script won't be able to access the type. See here.

  Create & build a C# script and execute it multiple times

  var script = CSharpScript.Create<int>("X*Y", globalsType: typeof(Globals));

  script.Compile();

  for (int i = 0; i < 10; i++)

  {

  Console.WriteLine((await script.RunAsync(new Globals { X = i, Y = i })).ReturnValue);

  }

  Create a delegate to a script

  The delegate doesn't hold compilation resources (syntax trees, etc.) alive.

  var script = CSharpScript.Create<int>("X*Y", globalsType: typeof(Globals));

  ScriptRunner<int> runner = script.CreateDelegate();

  for (int i = 0; i < 10; i++)

  {

  Console.WriteLine(await runner(new Globals { X = i, Y = i }));

  }

  Run a C# snippet and inspect defined script variables

  var state = await CSharpScript.RunAsync<int>("int answer = 42;");

  foreach (var variable in state.Variables)

  Console.WriteLine($"{variable.Name} = {variable.Value} of type {variable.Type}");

  Chain code snippets to form a script

  var script = CSharpScript.

  Create<int>("int x = 1;").

  ContinueWith("int y = 2;").

  ContinueWith("x + y");

   

  Console.WriteLine((await script.RunAsync()).ReturnValue);

  Continue script execution from a previous state

  var state = await CSharpScript.RunAsync("int x = 1;");

  state = await state.ContinueWithAsync("int y = 2;");

  state = await state.ContinueWithAsync("x+y");

  Console.WriteLine(state.ReturnValue);

  Create and analyze a C# script

  using Microsoft.CodeAnalysis;

   

  var script = CSharpScript.Create<int>("3");

  Compilation compilation = script.GetCompilation();

  //do stuff

  Compilation gives access to the full set of Roslyn APIs.

  Customize assembly loading

  using Microsoft.CodeAnalysis.Scripting.Hosting;

   

  using (var loader = new InteractiveAssemblyLoader())

  {

  var script = CSharpScript.Create<int>("1", assemblyLoader: loader);

  //do stuff

  }