Are there any .NET CLR/DLR implementations of ECMAScript?

Question

Does anyone know of real (i.. no vaporware) implementations of ECMAScript targeting the .NET CLR/DLR? Ideally something like what Rhino is

Answer 1

You should try Javascript .NET (http://javascriptdotnet.codeplex.com/) on Codeplex. They wrapped v8 with managed C++ and then you can use this library with a .NET application and it works like a charm. The open source offers some pretty good features if you ask me.

Cheers.

Answer 2

Nobody's mentioned ClearScript, so ClearScript.

It's not an implementation; it's an interop wrapper that supports V8, JScript and VBScript, with a really nice API to call into them from .NET code.

Example code from the CodePlex page:

using System;
using Microsoft.ClearScript;
using Microsoft.ClearScript.V8;

// create a script engine
using (var engine = new V8ScriptEngine())
{
    // expose a host type
    engine.AddHostType("Console", typeof(Console));
    engine.Execute("Console.WriteLine('{0} is an interesting number.', Math.PI)");

    // expose a host object
    engine.AddHostObject("random", new Random());
    engine.Execute("Console.WriteLine(random.NextDouble())");

    // expose entire assemblies
    engine.AddHostObject("lib", new HostTypeCollection("mscorlib", "System.Core"));
    engine.Execute("Console.WriteLine(lib.System.DateTime.Now)");

    // create a host object from script
    engine.Execute(@"
        birthday = new lib.System.DateTime(2007, 5, 22);
        Console.WriteLine(birthday.ToLongDateString());
    ");

    // use a generic class from script
    engine.Execute(@"
        Dictionary = lib.System.Collections.Generic.Dictionary;
        dict = new Dictionary(lib.System.String, lib.System.Int32);
        dict.Add('foo', 123);
    ");

    // call a host method with an output parameter
    engine.AddHostObject("host", new HostFunctions());
    engine.Execute(@"
        intVar = host.newVar(lib.System.Int32);
        found = dict.TryGetValue('foo', intVar.out);
        Console.WriteLine('{0} {1}', found, intVar);
    ");

    // create and populate a host array
    engine.Execute(@"
        numbers = host.newArr(lib.System.Int32, 20);
        for (var i = 0; i < numbers.Length; i++) { numbers[i] = i; }
        Console.WriteLine(lib.System.String.Join(', ', numbers));
    ");

    // create a script delegate
    engine.Execute(@"
        Filter = lib.System.Func(lib.System.Int32, lib.System.Boolean);
        oddFilter = new Filter(function(value) {
            return (value & 1) ? true : false;
        });
    ");

    // use LINQ from script
    engine.Execute(@"
        oddNumbers = numbers.Where(oddFilter);
        Console.WriteLine(lib.System.String.Join(', ', oddNumbers));
    ");

    // call a script function
    engine.Execute("function print(x) { Console.WriteLine(x); }");
    engine.Script.print(DateTime.Now.DayOfWeek);

    // examine a script object
    engine.Execute("person = { name: 'Fred', age: 5 }");
    Console.WriteLine(engine.Script.person.name);
}

Answer 3

You can use Jscript.net and it will actually work with arbitrary javascript code; You just need to turn off "fast mode" by compiling with jsc /fast- bar.js

I have not tested this; I just noticed it while reading this post and figured it would be another reasonable solution. MSDN Has the docs for this option and what the limitations are if you don't use it.