gistfile1.js

var DISPATCH_TABLE = {};


DISPATCH_TABLE.Person = {
    intro: function(_self) {
        return "I am just a Person,and my name is " + _self.name;
    }
};
TYPE_TABLE = {};

ANCESTOR_TABLE = {};


Array.prototype.first = function(predicate) {
    for (var i = 0, l = this.length; i < l; i++) {
        if (predicate(this[i]))
            return this[i];
    }
}

Array.prototype.flatten = function() {
    return Array.prototype.concat.apply([], this);
}


function sendMessage(object, message, args) {
    var tables = [object._singleton_, ancestors(object._class_).map(function(classOrModule) {
        return DISPATCH_TABLE[classOrModule]
    })].flatten();

    var resolved = tables.first(function(table) {
        return !!table[message];
    });
    var method = resolved[message];
    return method(object, args);
}

function defClass(className, dispatchTable) {
    DISPATCH_TABLE[className] = dispatchTable;
    return _classAncestor(className)
}

function defModule(moduleName, dispatchTable) {
    DISPATCH_TABLE[moduleName] = dispatchTable;
}

function extend(className, parentName) {
    var ancestor = _classAncestor(className);
    if (ancestor) throw ("multi inheritance");
    return _classAncestor(className, parentName);
}

function include(className, moduleName) {
    var ancestor = _includeAncestor(className);
    ancestor.unshift(moduleName);
    return ancestor;
}

function prepend(className, moduleName) {
    var ancestor = _prependAncestor(className);
    ancestor.unshift(moduleName);
    return ancestor;
}

function singleton(object, dispatchTable) {
    object._singleton_ = dispatchTable;
}

function _nullThenSet(obj, key, defaultValue) {
    if (!obj[key]) {
        obj[key] = defaultValue
    }
    return obj[key];
}

function _classAncestor(className, setter) {
    var ancestor = _nullThenSet(ANCESTOR_TABLE, className, {});
    if (setter) {
        ancestor.parent = setter;
    }
    return ancestor.parent;
}

function _includeAncestor(className, setter) {
    var ancestor = _nullThenSet(ANCESTOR_TABLE, className, {});
    if (setter) {
        ancestor.include = setter;
    }
    return _nullThenSet(ancestor, "module", []);
}

function _prependAncestor(className, setter) {
    var ancestor = _nullThenSet(ANCESTOR_TABLE, className, {});
    if (setter) {
        ancestor.prepend = setter;
    }
    return _nullThenSet(ancestor, "prepend", []);
}


function ancestors(className) {
    return [
        _prependAncestor(className).map(ancestors).flatten(),
        className,
        _includeAncestor(className).map(ancestors).flatten(),
        _classAncestor(className)].flatten().filter(function(e) {
        return !!e
    });
}
defClass("Parent", {});
defClass("Clazz", {});
defModule("A", {});
defModule("B", {});
defModule("C", {});
defModule("D",{});
extend("Clazz", "Parent");
include("Clazz", "A");
include("Clazz", "B");
include("A","D");
prepend("Clazz", "C");


console.log(ancestors('Clazz'));

/*


Work3-1
// class Child < Parent end
function extend(childName,parentName) {
    
}

Work3-2
// class Child 
//   include Module
// end
function include(targetClassName,moduleName){

}

Work3-3
// class Child
//   prepend Module
// end
function prepend(targetClassName,moduleName){

}

Work3-4
// class << object
//
// end
function singleton(object,dispatchTable){

}

Work3-5
implement method_missing

sendMessage(me,'no_such_a_method') => NoSuchAMethod

Work3-6
implement double dispatch

DISPATCH_TABLE['ClassA']['ClassB'].collide = function(){}

sendMessage([me,you],'collide')


*/