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

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);
}