dess中一个简单的多路委托的实现

var SDelegate = function(f, b, c) { 
if (b) { 
this.asFunction_ = function() { 
return f.apply(b, arguments); 
} 
} else { 
this.asFunction_ = function() { 
return f.apply(this, arguments); 
} 
} 
this.method_ = f; 
this.binding_ = b; 
this.continus = c; 
} 
SDelegate.composite = function(d) { 
if (d.continus) { 
var con = d.continus.composited_ = SDelegate.composite(d.continus); 
var method = d.asFunction_; 
return function() { 
con.apply(this, arguments); 
return method.apply(this, arguments); 
} 
} else { 
return d.asFunction_; 
} 
} 
SDelegate.prototype.call = function() { 
if (!this.composited_) this.composited_ = SDelegate.composite(this); 
return this.composited_.apply(arguments[0], Array.prototype.slice.call(arguments, 1)); 
} 
SDelegate.prototype.remove = function() { 
var removeP = function(parent, item, test, data) { 
if (!item) return; 
parent.composited_ = item.composited_ = null; 
if (test(item, data)) { 
parent.continus = item.continus; 
removeP(parent, item.continus, test, data); 
} else { 
removeP(item, item.continus, test, data); 
} 
}; 
return function(test, data) { 
var p = this; 
if (test(this, data)) { 
p = this.continus; 
} 
removeP(p, p.continus, test, data); 
p.composited_ = null; 
return p; 
} 
}(); 
SDelegate.prototype.append = function(f, b) { 
return new SDelegate(f, b, this); 
}

这个SDelegate用起来可能会比较诡异，比如很多操作都要重新赋值。Dess中，SDelegate主要用于一些特定场合，如DOM事件派发。