nitoyon · September 21, 2011 15:49
diff --git a/async_await_js.html b/async_await_js.html
 <html>
 <body onload="init2()">
 <script type="application/javascript;version=1.7">
 /*===========================================================================*
 *    Test Implementation of .NET 5 `await` and `async` in JavaScript 1.7
 *===========================================================================*
 * !!!!! This sample only works on Firefox !!!!!
 * (Other browsers don't support `yield` statement)
 *===========================================================================*
 * use `async` function like:
 *     // C#: async void func_name(){ }
 *     var func_name = async(function(){
 *         // function body here
 *     });
 *
 * use `yield` statement instead of `await`:
 *     // C#: ret = await func_name();
 *     var ret = yield func_name();
 *
 * use `yield` statement in order to return value in `async` function:
 *     // C#: return 3;
 *     yield 3;
 *===========================================================================*/


 /*===========================================================================*
 *                              Test Code
 *===========================================================================*
 * Output of init1():
 *   doXhr start
 *   doXhr end
 *   finished: true, status: 200
 *   finished: false, status: 404
 *
 * Output of init2():
 *   doXhr start
 *   finished: true, status: 200
 *   finished: false, status: 404
 *   doXhr end: 3
 *===========================================================================*/
 function init1(){
 	log("doXhr start");
 	doXhrTwice();
 	log("doXhr end");
 }

 var init2 = async(function(){
 	log("doXhr start");
 	var ret = yield doXhrTwice();
 	log("doXhr end: " + ret);
 });

 var doXhrTwice = async(function(){
 	var xhr = awaitable(new XMLHttpRequest());
 	xhr.open('GET', location.href, true);
 	var result = yield xhr.send(null);
 	log("finished: " + result +  ", status: " + xhr.status);

 	xhr = awaitable(new XMLHttpRequest());
 	xhr.open('GET', "not_found.png", true);
 	result = yield xhr.send(null);
 	log("finished: " + result +  ", status: " + xhr.status);

 	yield 3;
 });

 // log output
 function log(text){
 	var p = document.createElement("p");
 	p.appendChild(document.createTextNode(text));
 	document.getElementById("logContainer").appendChild(p);
 }

 /*===========================================================================*
 *                          Library starts...
 *===========================================================================*/

 // make object awaitable.
 // 
 function awaitable(obj){
 	if (obj.toString() == "[object XMLHttpRequest]"){
 		var xhr = obj;
 		var _send = xhr.send;
 		xhr.send = function(){
 			var task = new Task();
 			xhr.onreadystatechange = function(){
 				if (xhr.readyState == 4){
 					if (xhr.status == 200){
 						task.success();
 					} else {
 						task.error();
 					}
 				}
 			};
 			_send.apply(xhr, arguments);
 			return task
 		};
 	}
 	return obj;
 }

 // Emulate .NET 5 `async` keyword.
 // Function that contains `await` keyword must be passed to
 // `async` function.
 function async(f){
 	var self = this;
 	return function(){
 		var task = new Task();

 		// call original function.
 		var ret = f.apply(self, arguments);

 		// if it doesn't return generator, returns it.
 		if (ret != "[object Generator]"){
 			return ret;
 		}

 		// call generator's next() method.
 		task.generator = ret;
 		task.goNext();

 		return task;
 	};
 }

 // Task constructor
 function Task(){
 	this.id = ++Task.id;
 	this.generator = null;
 	this.isCompleted = false;
 	this.result = undefined;
 	this.exception = null;
 	if (Task.debug) console.log("task%d: generated", this.id);
 }
 Task.id = 0;
 Task.debug = false;

 Task.prototype = {
 	goNext: function(){
 		if (Task.debug) console.log("task%d: goNext called", this.id);

 		// if there's no generator, task is done.
 		if (!this.generator){
 			this.complete();
 			return;
 		}

 		// get next child task or result value.
 		try{
 			var ret;
 			if (this.childTask){
 				ret = this.generator.send(this.childTask.result);
 			} else {
 				ret = this.generator.next();
 			}
 		} catch (e) {
 			if (e instanceof StopIteration) {
 				// no child task.
 				if (Task.debug) console.log("task%d: StopIteration", this.id);
 				this.complete();
 				return;
 			}
 			throw e;
 		}

 		// When yielded object is not task, it is result value.
 		if (ret.__proto__ != Task.prototype){
 			if (Task.debug) console.log("task%d: return with value %s", this.id, ret);
 			this.result = ret;
 			this.complete();
 			return;
 		}

 		// task is yielded!  call the async function.
 		var childTask = ret;
 		if (Task.debug) console.log("task%d: child task %d is returned", this.id, childTask.id);
 		childTask.parent = this;
 		this.childTask = childTask;
 	},

 	complete: function(){
 		if (Task.debug) console.log("task%d: done", this.id);
 		this.isCompleted = true;
 		if (this.generator){
 			this.generator.close();
 		}

 		if (this.parent){
 			this.parent.goNext();
 		}
 	},

 	throw: function(ex){
 		if (Task.debug) console.log("task%d: excepion %s", this.id, ex);
 		this.exception = ex;
 		if (this.parent && this.parent.generator){
 			this.parent.generator.throw(ex);
 		}
 	},

 	success: function(){
 		if (Task.debug) console.log("task%d: success", this.id);
 		this.result = true;
 		this.complete();
 	},

 	error: function(){
 		if (Task.debug) console.log("task%d: error", this.id);
 		this.result = false;
 		this.complete();
 	}
 };
 </script> 
 <div id="logContainer">
 </div>
 </body>
 </html>
	<html>
	<body onload="init2()">
	<script type="application/javascript;version=1.7">
	/===========================================================================
	* Test Implementation of .NET 5 `await` and `async` in JavaScript 1.7
	===========================================================================
	* !!!!! This sample only works on Firefox !!!!!
	* (Other browsers don't support `yield` statement)
	===========================================================================
	* use `async` function like:
	* // C#: async void func_name(){ }
	* var func_name = async(function(){
	* // function body here
	* });
	*
	* use `yield` statement instead of `await`:
	* // C#: ret = await func_name();
	* var ret = yield func_name();
	*
	* use `yield` statement in order to return value in `async` function:
	* // C#: return 3;
	* yield 3;
	===========================================================================/


	/===========================================================================
	* Test Code
	===========================================================================
	* Output of init1():
	* doXhr start
	* doXhr end
	* finished: true, status: 200
	* finished: false, status: 404
	*
	* Output of init2():
	* doXhr start
	* finished: true, status: 200
	* finished: false, status: 404
	* doXhr end: 3
	===========================================================================/
	function init1(){
	log("doXhr start");
	doXhrTwice();
	log("doXhr end");
	}

	var init2 = async(function(){
	log("doXhr start");
	var ret = yield doXhrTwice();
	log("doXhr end: " + ret);
	});

	var doXhrTwice = async(function(){
	var xhr = awaitable(new XMLHttpRequest());
	xhr.open('GET', location.href, true);
	var result = yield xhr.send(null);
	log("finished: " + result + ", status: " + xhr.status);

	xhr = awaitable(new XMLHttpRequest());
	xhr.open('GET', "not_found.png", true);
	result = yield xhr.send(null);
	log("finished: " + result + ", status: " + xhr.status);

	yield 3;
	});

	// log output
	function log(text){
	var p = document.createElement("p");
	p.appendChild(document.createTextNode(text));
	document.getElementById("logContainer").appendChild(p);
	}

	/===========================================================================
	* Library starts...
	===========================================================================/

	// make object awaitable.
	//
	function awaitable(obj){
	if (obj.toString() == "[object XMLHttpRequest]"){
	var xhr = obj;
	var _send = xhr.send;
	xhr.send = function(){
	var task = new Task();
	xhr.onreadystatechange = function(){
	if (xhr.readyState == 4){
	if (xhr.status == 200){
	task.success();
	} else {
	task.error();
	}
	}
	};
	_send.apply(xhr, arguments);
	return task
	};
	}
	return obj;
	}

	// Emulate .NET 5 `async` keyword.
	// Function that contains `await` keyword must be passed to
	// `async` function.
	function async(f){
	var self = this;
	return function(){
	var task = new Task();

	// call original function.
	var ret = f.apply(self, arguments);

	// if it doesn't return generator, returns it.
	if (ret != "[object Generator]"){
	return ret;
	}

	// call generator's next() method.
	task.generator = ret;
	task.goNext();

	return task;
	};
	}

	// Task constructor
	function Task(){
	this.id = ++Task.id;
	this.generator = null;
	this.isCompleted = false;
	this.result = undefined;
	this.exception = null;
	if (Task.debug) console.log("task%d: generated", this.id);
	}
	Task.id = 0;
	Task.debug = false;

	Task.prototype = {
	goNext: function(){
	if (Task.debug) console.log("task%d: goNext called", this.id);

	// if there's no generator, task is done.
	if (!this.generator){
	this.complete();
	return;
	}

	// get next child task or result value.
	try{
	var ret;
	if (this.childTask){
	ret = this.generator.send(this.childTask.result);
	} else {
	ret = this.generator.next();
	}
	} catch (e) {
	if (e instanceof StopIteration) {
	// no child task.
	if (Task.debug) console.log("task%d: StopIteration", this.id);
	this.complete();
	return;
	}
	throw e;
	}

	// When yielded object is not task, it is result value.
	if (ret.__proto__ != Task.prototype){
	if (Task.debug) console.log("task%d: return with value %s", this.id, ret);
	this.result = ret;
	this.complete();
	return;
	}

	// task is yielded! call the async function.
	var childTask = ret;
	if (Task.debug) console.log("task%d: child task %d is returned", this.id, childTask.id);
	childTask.parent = this;
	this.childTask = childTask;
	},

	complete: function(){
	if (Task.debug) console.log("task%d: done", this.id);
	this.isCompleted = true;
	if (this.generator){
	this.generator.close();
	}

	if (this.parent){
	this.parent.goNext();
	}
	},

	throw: function(ex){
	if (Task.debug) console.log("task%d: excepion %s", this.id, ex);
	this.exception = ex;
	if (this.parent && this.parent.generator){
	this.parent.generator.throw(ex);
	}
	},

	success: function(){
	if (Task.debug) console.log("task%d: success", this.id);
	this.result = true;
	this.complete();
	},

	error: function(){
	if (Task.debug) console.log("task%d: error", this.id);
	this.result = false;
	this.complete();
	}
	};
	</script>
	<div id="logContainer">
	</div>
	</body>
	</html>