gistfile1.txt

// Totally naive mixin for demonstration purposes
var mixInProperties = function (to, from) {
  for (var p in from) {
    to[p] = from[p];
  }
}

// Base pseudoclass
var InheritedCodeObj = function (id) {
  this.id = id || '(none)';
  // In classical inheritance, this would be 'super'
  this.inheritedFunction = function () {
    console.log('Calling an inherited function on ' + this.id);
  };
};

// Singleton, an instance
var mixinObj = new function () {
  this.mixedInFunction = function () {
    console.log('Calling a mixed-in function on ' + this.id);
  };
}();

// Child pseudoclass for composition
var CompositionObj = function (parentObj) {
  this.parentObj = parentObj;
  this.delegatedFunction = function () {
    console.log('Calling a function delegated to ' +
        this.parentObj.id + '\'s child obj.');
  };
};

// Sub pseudoclass
var BaseObj = function (id) {
  this.id = id;
  this.childObj = null;

  this.locallyDefinedFunction = function () {
    this.inheritedFunction();
    this.mixedInFunction();
    this.childObj.delegatedFunction();
    console.log('Calling a locally defined function on ' +
        this.id);
  };

};
// Inherit some stuff via simple prototypal inheritance
BaseObj.prototype = new InheritedCodeObj();


// Instantiate obj with single prototypal inheritance
var a = new BaseObj('a');
// Mix in some stuff
mixInProperties(a, mixinObj);
// Add a child for composition/delegation
a.childObj = new CompositionObj(a);
// Call a function that demonstrates a bunch of different
// ways to do code reuse
a.locallyDefinedFunction();