gistfile1.js

var DISPATCH_TABLE = {};


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

DISPATCH_TABLE.Student = {
    intro : function(_self){
        return "I am a Student,and my name is "+_self.name;
    },
    study : function(_self){
        return "I'm studying...";
    }
};

DISPATCH_TABLE.Superman = {
    intro : function(_self) {
        return "Hahaha! I'm a "+_self.name;
    }
};

DISPATCH_TABLE.Flyable = {
    fly : function(_self) {
        return "Shoooooooooooooooon!";
    }
};

DISPATCH_TABLE.Mant = {
    /*
    fly : function(_self) {
        return "Fooo!";
    }
    */
};

DISPATCH_TABLE.Accelerator = {
    fly : function(_self) {
        return "Bhoooouuuououoouououou!";
    }
};


var CLASS_HIERARCY = {};
var MODULE_HIERARCY = {};
var PREPEND_MODULE_HIERARCY = {};

var me = {
    _class_ : 'Person',
    name : 'daichi hiroki',
    age  : 30,
    study : "computer science"
};

var him = {
    _class_ : 'Student',
    name : 'hoge piyonosuke',
    age  : 20,
    study : "complex system"
};

var superman = {
    _class_ : 'Superman',
    name : 'Tarou',
    age : 777
};
    

function sendMessage(object,message,args){
    function findMethod(className, message) {

        var method;

        // traverse prepend hierarchy
        for (var i = 0; i < PREPEND_MODULE_HIERARCY[className].length; i ++) {
            var moduleName = PREPEND_MODULE_HIERARCY[className][i];
            method = findMethod(moduleName, message);
            if (method !== undefined) { return method; }
        }

        // search current dispatch table
        var klass = DISPATCH_TABLE[className];
        if (klass === undefined) { return null; }

        var method = klass[message];
        if (method !== undefined) { return method; }

        // traverse include hierarchy
        for (var i = 0; i < MODULE_HIERARCY[className].length; i ++) {
            var moduleName = MODULE_HIERARCY[className][i];
            method = findMethod(moduleName, message);
            if (method !== undefined) { return method; }
        }
        
        // resolve next inherit relation
        return findMethod(CLASS_HIERARCY[className], message);
    }

    var method = findMethod(object._class_, message);
    if (method === null) { return null; }
    return method( object ,args );
}



//Work3-1
// class Child < Parent end
function extend(childName,parentName) {
   CLASS_HIERARCY[childName] = parentName; 
}

//Work3-2
// class Child 
//   include Module
// end
function include(targetClassName,moduleName){
    var classList = MODULE_HIERARCY[targetClassName];
    if (classList === undefined) {
        MODULE_HIERARCY[targetClassName] = [moduleName];
        return ;
    }

    classList.unshift(moduleName);
}

//Work3-3
// class Child
//   prepend Module
// end
function prepend(targetClassName,moduleName){
    var classList = PREPEND_MODULE_HIERARCY[targetClassName];
    if (classList === undefined) {
        PREPEND_MODULE_HIERARCY[targetClassName] = [moduleName];
        return ;
    }

    classList.unshift(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')


*/

// work 3-1
console.log(sendMessage(me,'intro'));
extend('Student', 'Person');
console.log(sendMessage(him,'intro'));
console.log(sendMessage(him,'study'));

// work 3-2
include('Superman', 'Flyable');
include('Mant', 'Accelerator');
include('Superman', 'Mant');
console.log(sendMessage(superman, 'intro'));
console.log(sendMessage(superman, 'fly'));