4 different ways to execute IronPython code using the DLR Hosting API

seshadripv — Tue, 29 Jul 2008 06:55:00 GMT

The Hosting API offers 4 different sets of methods to execute a script. These methods provide hosts - managed application in C#, VB and other .NET languages - with powerful, convenient and versatile ways to execute scripts from the DLR languages like IronPython, IronRuby etc. ( Though the title mentions just IronPython, this post applies to others like IronRuby, ToyScript etc as well)

I have put together a short summary of these methods and the types that define them. The descriptions found here are shortened versions of the descriptions found in the Hosting API spec. Please refer to the same for more specific details about the type and the method.

The types that define these method families are ScriptRuntime, ScriptScope, ScriptSource and CompiledCode.

ScriptRuntime

This class is the starting point for hosting. ScriptRuntime represents global script state. This includes referenced assemblies, a "global object" (ScriptRuntime.Globals), "published" scopes (scopes bound to a name on Globals), available language engines, etc.

public ScriptScope ExecuteFile(string path);

This method executes the source identified in the path argument and returns the new ScriptScope in which the source executed. ExecuteFile determines the language engine to use from the path's extension and the ScriptRuntime's configuration, comparing extensions case-insensitively.

The path is an absolute pathname or a filename that naturally resolves with standard .NET BCL file open calls.

ScriptScope

This class represents a namespace essentially. Hosts can bind variable names in ScriptScopes, fetch variable values, etc. Hosts can execute code within scopes for distinct name bindings.

public object Execute(string code);

public T Execute<T>(string code);

These methods return objects that result from executing code in the string argument.

ScriptSource

ScriptSource represents source code and offers a variety of ways to execute or compile the source. You can get ScriptSources from factory methods on ScriptEngine, and ScriptSources are tied to the engine that created them.

public object Execute(ScriptScope scope);

public ObjectHandle ExecuteAndWrap(ScriptScope scope);

public T Execute<T>(ScriptScope scope);

public int ExecuteProgram();

These methods execute the source code and return the result. All but one method executes the code in the specified ScriptScope.

CompiledCode

CompiledCode represents code that has been compiled to execute repeatedly without having to compile it each time, and it represents the default ScriptScope the code runs in. You can also execute the code in any ScriptScope if you need it to execute in a clean scope each time, or you want to accumulate side effects from the code in another scope.

public object Execute() { }

public object Execute(ScriptScope scope) { }

public ObjectHandle ExecuteAndWrap() { }

public ObjectHandle ExecuteAndWrap(ScriptScope scope) { }

public T Execute<T>() { }

public T Execute<T>(ScriptScope scope) { }

Unlike the ScriptSource’s execute methods, these do not compile the code again.

A few of these methods can be found in the samples from the earlier blog posts. For more details and documentation about these methods and types please refer to the Hosting API spec.

DLR Hosting and related stuff... : Execute

4 different ways to execute IronPython code using the DLR Hosting API