微软自家的.Net下的JavaScript引擎——ClearScript

之前我介绍过一个开源的.Net下的Javascript引擎Javascript .NET，今天发现微软自己也开源了一个JavaScript引擎——ClearScript（当然，也支持VB Script）。

由于是微软发布的，基本上没有什么好挑剔的地方，稳定而强大，不过不支持WinRT。下面这个则是官方示例，就不做更多介绍了，感兴趣的朋友可以去CodePlex看下。

 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));
     ");

     // use a dynamic host object
     engine.Execute(@"
         expando = new lib.System.Dynamic.ExpandoObject();
         expando.foo = 123;
         expando.bar = 'qux';
         delete expando.foo;
     ");

     // 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);
 }