egonelbre/dci.js

## dci.js
// allows easily making an Actor with a Role
// if it's already an actor the context will be attached.
Object.defineProperty(Object.prototype, "as", {enumerable: false, value : function(role){
  // this will add a role to the object
  if(this.__isActor__) {
    this.__addRole__(role);
    return this;
  }

  // if this is not an actor -
  // an object that can play a role, we must make a new actor
  var actor = new Actor(this);
  actor.__addRole__(role);
  return actor;
}});

function sameObject(a, b){
  if(a.__isActor__)
    a = a.original;
  if(b.__isActor__)
    b = b.original;
  return a === b;
}

// this defines a Context
function Context(fn) {
  return function(){
    fn.__ctx__ = GUID();
    return fn.apply(null, arguments);
  };
}

// this is for creating a new Role
// also attaches the context of the methods
// should only be called in a Context
function Role(methods) {
  var role = {
    __ctx__: currentContext(),
    __methods__: methods
  };
  for(var e in methods) {
    methods[e].__ctx__ = role.__ctx__;
  }
  return role;
}

// for using anonymous methods
// this will attach the correct context otherwise the function will be contextless
function Fn(fn) {
  var ctx = currentContext();
  fn.__ctx__ = ctx;
  return fn;
}

function Methods(obj){
  var ctx = currentContext();
  obj.__ctx__ = ctx;
  for(var name in obj){
    if(typeof obj[name] ){
      obj[name].__ctx__ = ctx;
    }
  }
  return obj;
}

// this defines an actor capable of dispatching to roles depending on context
// ! should not be used directly
function Actor(original) {
  // actor specific things
  this.__isActor__ = true;
  this.__original__ = original;
  var contexts = { /*context : [Role1, Role2, Role3]*/ };

  // this method makes a dispatcher that finds the correct method
  // depending on the calling context
  var mkDispatcher = function(name) {
    var fx = function() {
        var ctx = currentContext(),
          roles = contexts[ctx],
          fn = original[name];
        if(roles) {
          for(var i = 0; i < roles.length; i += 1) {
            var methods = roles[i].__methods__;
            if(methods[name]) {
              fn = methods[name];
              break;
            }
          }
        }
        if(!fn){
          throw new Error("undefined method '" + name + "'");
        }
        return fn.apply(this, arguments);
      };
    fx.__ctx__ = "Dispatcher[" + name + "]"; // for debugging
    return fx;
  };

  // for dispatching get/set to the original
  var redirect = function(from, to, name){
      from.__defineGetter__(name, function(){
        return to[name];
      });
      from.__defineSetter__(name, function(v){
        to[name] = v;
      });
  };

  // for dispatching calls to the original
  this.constructor = original.constructor;
  for(var name in original){
    if(typeof original[name] === "function"){
      this[name] = mkDispatcher(name);
    } else {
      redirect(this, original, name);
    }
  }

  // this just adds a role to the actor table
  // and makes additional dispatchers for role methods
  this.__addRole__ = function(role) {
    var ctx = role.__ctx__;
    if(!contexts[ctx])
      contexts[ctx] = [];
    contexts[ctx].unshift(role);

    var methods = role.__methods__;
    for(var name in methods) {
      if(!methods.hasOwnProperty(name) || this.hasOwnProperty(name))
        continue;
      this[name] = mkDispatcher(name);
    }
  };
}

// this finds the current context
// undefined if, none found
// ! should not be used directly
function currentContext() {
  return currentContext.caller.caller.__ctx__;
}

// used for uniquely identifyig contexts
function GUID() {
  // http://www.ietf.org/rfc/rfc4122.txt
  var s = [];
  var hexDigits = "0123456789abcdef";
  for(var i = 0; i < 36; i++) {
    s[i] = hexDigits[Math.random() * 0x10 | 0];
  }
  s[14] = "4";
  s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1);
  s[8] = s[13] = s[18] = s[23] = "-";
  var uuid = s.join("");
  return uuid;
}

## example.html
<!doctype html>
<title>DCI Test</title>
<pre id="log"></pre>
<script src="dci.js"></script>
<script>
write = function() {
  var lg = document.getElementById("log"),
    args = Array.prototype.slice.apply(arguments),
    line = args.join(", ") + "<br>";
  lg.innerHTML += line;
};

function makePlayerTalk(player) {
  player.say();
}

var Battle = Context(function(alpha, beta) {
  var Bear = Role({
    say: function() {
      write( "[" + this.name + "] " + "Grrrr.....");
    },
    touch: function(other) {
      this.say();
      other.say();
    }
  });

  var Lion = Role({
    say: function() {
      write( "[" + this.name + "] " + "Meow....");
    },
    touch: function(other) {
      this.say();
      other.say();
    }
  });

  return Methods({
    doit : function(){
        var lion = alpha.as(Lion),
            alphaBear = alpha.as(Bear),
            bear = beta.as(Bear);

        write("# Conversing");
        lion.say();
        bear.say();
        alphaBear.say();

        write("# lion touching the bear");
        lion.touch(bear);

        write("# making alpha talk");
        makePlayerTalk(lion);

        write("# making beta talk");
        makePlayerTalk(bear);
    }
  });
});

var player = {
  name: "Jack",
  say: function() {
    write( "[" + this.name + "] " + "says Hello!");
  }
};

var cpu = {
  name: "Cyborg",
  say: function() {
    write( "[" + this.name + "] " + "bleeps Hello!");
  }
};

var battle = Battle(player, cpu);
battle.doit();
/* output

# Conversing
[Jack] Meow....
[Cyborg] Grrrr.....
[Jack] Grrrr.....
# lion touching the bear
[Jack] Meow....
[Cyborg] Grrrr.....
# making alpha talk
[Jack] says Hello!
# making beta talk
[Cyborg] bleeps Hello!

*/
</script>
	// allows easily making an Actor with a Role
	// if it's already an actor the context will be attached.
	Object.defineProperty(Object.prototype, "as", {enumerable: false, value : function(role){
	// this will add a role to the object
	if(this.__isActor__) {
	this.__addRole__(role);
	return this;
	}

	// if this is not an actor -
	// an object that can play a role, we must make a new actor
	var actor = new Actor(this);
	actor.__addRole__(role);
	return actor;
	}});

	function sameObject(a, b){
	if(a.__isActor__)
	a = a.original;
	if(b.__isActor__)
	b = b.original;
	return a === b;
	}

	// this defines a Context
	function Context(fn) {
	return function(){
	fn.__ctx__ = GUID();
	return fn.apply(null, arguments);
	};
	}

	// this is for creating a new Role
	// also attaches the context of the methods
	// should only be called in a Context
	function Role(methods) {
	var role = {
	__ctx__: currentContext(),
	__methods__: methods
	};
	for(var e in methods) {
	methods[e].__ctx__ = role.__ctx__;
	}
	return role;
	}

	// for using anonymous methods
	// this will attach the correct context otherwise the function will be contextless
	function Fn(fn) {
	var ctx = currentContext();
	fn.__ctx__ = ctx;
	return fn;
	}

	function Methods(obj){
	var ctx = currentContext();
	obj.__ctx__ = ctx;
	for(var name in obj){
	if(typeof obj[name] ){
	obj[name].__ctx__ = ctx;
	}
	}
	return obj;
	}

	// this defines an actor capable of dispatching to roles depending on context
	// ! should not be used directly
	function Actor(original) {
	// actor specific things
	this.__isActor__ = true;
	this.__original__ = original;
	var contexts = { /context : [Role1, Role2, Role3]/ };

	// this method makes a dispatcher that finds the correct method
	// depending on the calling context
	var mkDispatcher = function(name) {
	var fx = function() {
	var ctx = currentContext(),
	roles = contexts[ctx],
	fn = original[name];
	if(roles) {
	for(var i = 0; i < roles.length; i += 1) {
	var methods = roles[i].__methods__;
	if(methods[name]) {
	fn = methods[name];
	break;
	}
	}
	}
	if(!fn){
	throw new Error("undefined method '" + name + "'");
	}
	return fn.apply(this, arguments);
	};
	fx.__ctx__ = "Dispatcher[" + name + "]"; // for debugging
	return fx;
	};

	// for dispatching get/set to the original
	var redirect = function(from, to, name){
	from.__defineGetter__(name, function(){
	return to[name];
	});
	from.__defineSetter__(name, function(v){
	to[name] = v;
	});
	};

	// for dispatching calls to the original
	this.constructor = original.constructor;
	for(var name in original){
	if(typeof original[name] === "function"){
	this[name] = mkDispatcher(name);
	} else {
	redirect(this, original, name);
	}
	}

	// this just adds a role to the actor table
	// and makes additional dispatchers for role methods
	this.__addRole__ = function(role) {
	var ctx = role.__ctx__;
	if(!contexts[ctx])
	contexts[ctx] = [];
	contexts[ctx].unshift(role);

	var methods = role.__methods__;
	for(var name in methods) {
	if(!methods.hasOwnProperty(name) \|\| this.hasOwnProperty(name))
	continue;
	this[name] = mkDispatcher(name);
	}
	};
	}

	// this finds the current context
	// undefined if, none found
	// ! should not be used directly
	function currentContext() {
	return currentContext.caller.caller.__ctx__;
	}

	// used for uniquely identifyig contexts
	function GUID() {
	// http://www.ietf.org/rfc/rfc4122.txt
	var s = [];
	var hexDigits = "0123456789abcdef";
	for(var i = 0; i < 36; i++) {
	s[i] = hexDigits[Math.random() * 0x10 \| 0];
	}
	s[14] = "4";
	s[19] = hexDigits.substr((s[19] & 0x3) \| 0x8, 1);
	s[8] = s[13] = s[18] = s[23] = "-";
	var uuid = s.join("");
	return uuid;
	}
	<!doctype html>
	<title>DCI Test</title>
	<pre id="log"></pre>
	<script src="dci.js"></script>
	<script>
	write = function() {
	var lg = document.getElementById("log"),
	args = Array.prototype.slice.apply(arguments),
	line = args.join(", ") + "<br>";
	lg.innerHTML += line;
	};

	function makePlayerTalk(player) {
	player.say();
	}

	var Battle = Context(function(alpha, beta) {
	var Bear = Role({
	say: function() {
	write( "[" + this.name + "] " + "Grrrr.....");
	},
	touch: function(other) {
	this.say();
	other.say();
	}
	});

	var Lion = Role({
	say: function() {
	write( "[" + this.name + "] " + "Meow....");
	},
	touch: function(other) {
	this.say();
	other.say();
	}
	});

	return Methods({
	doit : function(){
	var lion = alpha.as(Lion),
	alphaBear = alpha.as(Bear),
	bear = beta.as(Bear);

	write("# Conversing");
	lion.say();
	bear.say();
	alphaBear.say();

	write("# lion touching the bear");
	lion.touch(bear);

	write("# making alpha talk");
	makePlayerTalk(lion);

	write("# making beta talk");
	makePlayerTalk(bear);
	}
	});
	});

	var player = {
	name: "Jack",
	say: function() {
	write( "[" + this.name + "] " + "says Hello!");
	}
	};

	var cpu = {
	name: "Cyborg",
	say: function() {
	write( "[" + this.name + "] " + "bleeps Hello!");
	}
	};

	var battle = Battle(player, cpu);
	battle.doit();
	/* output

	# Conversing
	[Jack] Meow....
	[Cyborg] Grrrr.....
	[Jack] Grrrr.....
	# lion touching the bear
	[Jack] Meow....
	[Cyborg] Grrrr.....
	# making alpha talk
	[Jack] says Hello!
	# making beta talk
	[Cyborg] bleeps Hello!

	*/
	</script>