Enum

gistfile1.js

var scope = this;

function _Enum(ns, value, types, values){
    this.ns = ns;
    this.value = value;
    this.types = types;
    this.values = values;
    
    function validate(){
        var total = types.length;
        if(total != values.length)
            throw new Error("Lengths do not match");
        else {
            for(var i = 0; i < total; i++){
                var value = values[i];
                var type = types[i];
                if(typeof value === "number" && type == Number){
                    continue;
                } else if(typeof value === "string" && type == String){
                    continue;    
                } else if(typeof value == "object" && value instanceof type){
                    continue;                  
                } 
                
                throw new Error("Value(" + value +") is not instance of type(" + type + ")");                  
            }
        }
       
    }
    validate();
}
_Enum.prototype = {
    toString: function(){
        return this.ns + "." + this.value + "(" + this.values + ")";            
    }
};


function _enum(type) {
    function closure(ns, value, types){
        return function(){
            return new _Enum(ns, value, types, Array.prototype.slice.call(arguments));  
        }
    }
    
    for(var i in type){
        scope[i] = {};
        
        for(var k in type[i]){
            scope[i][k] = closure(i, k, type[i][k]);
        }                
    }
}

function match(value, matches){
    return matches[value.value].apply(scope, value.values);
}

_enum({
    Color: {
        Red:[Number],
        Green:[Number],
        Blue:[Number],
        RGB:[Number],
        ARGB:[Number, Number]
    }
});

var v = Color.ARGB(1, 0xff00ff);

var value = match(v, {
    Red: function(col) {
        return col.toString(16);
    },
    ARGB: function(alpha, col) {
        return ((0xff000000 * alpha) + col).toString(16);
    }
});

alert(value);​