鐃淳わ申鐃緒申鐃夙思って書いてみわ申鐃緒申導鐃緒申鐃緒申鐃緒申辰判鐃緒申茲随申里如鐃�

Demo

鐃夙りあ鐃緒申鐃緒申鐃緒申鐃緒申粉鐃緒申鐃緒申鐃�





Implementation


(function(){

var Lazy = function(a, f){
    for (var i = 0, l = a.length; i < l; i++) this[i] = a[i];
    this.length  = a.length;
    this.promise = f;
    this.defer   = [];
};

Lazy.prototype = [];
(function(o){
    for (p in o) Lazy.prototype[p] = o[p];
})({
    extend:function(n){
        if (!n) n = this.length;
        for (var i = this.length; i <= n; i++) this.push(this.promise(i));
        return this;
    },
    map:function(f){
        var that = new Lazy(this, this.promise);
        that.defer = Array.prototype.slice.apply(this.defer);
        that.defer.push(f);
        return that;
    },
    filter:function(f){
        var that = new Lazy(this, this.promise);
        that.defer = Array.prototype.slice.apply(this.defer);
        that.defer.push(function(e){ return f(e) ? e : null });
        return that;
    },
    take:function(n){
        if (n <= 0){
            return new Lazy([]);
        } else if (! this.defer.length){
            return new Lazy(this.extend(n-1).slice(0, n));
        }else{
            var ret = [], i = 0, e, j;
            loop: while (ret.length < n){
                e = this.extend(i)[i++];
                for (j = 0, l = this.defer.length; j < l; j++){
                    e = this.defer[j](e);
                    if (e === null) continue loop;
                }
                ret.push(e);
            }
            return new Lazy(ret);
        }
    },
    get:function(n){
        return this.take(n+1)[n];
    },
    toString:function(){
        return Array.prototype.slice.apply(this) + '';
    }
});

Array.Lazy = Lazy;

})();



    

  • 鐃緒申鐃緒申的鐃淑考わ申鐃緒申Tie::Array::Lazy鐃緒申同鐃緒申鐃叔￥申足鐃緒申覆鐃緒申鐃緒申任鐃緒申鐃緒申辰鐃緒申蕕緒申鐃緒申this.promise鐃緒申鐃緒申録鐃緒申鐃緒申鐃舜随申鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申錣誌申泙鐃緒申鐃�
    • 

  • Tie::Array::Lazy鐃夙逸申辰憧鐃緒申鐃銃�鐃緒申任覆鐃緒申里蓮鐃�this[n]鐃緒申this.get(n)鐃塾違い鐃薯見わ申个鐃緒申錣�鐃所い鐃緒申鐃緒申鐃緒申鐃殉わ申鐃緒申Ruby鐃淳わ申鐃緒申鐃緒申[]鐃緒申鐃緒申鐃緒申鐃出￥申鐃初イ鐃宿駕申能鐃淑メソ鐃獣ドならそ鐃緒申鐃緒申鐃緒申鐃塾でわ申鐃緒申鐃緒申
    • 

  • 鐃緒申鐃銃わ申鐃縮り、Array鐃緒申鐃縦ワ申鐃緒申鐃緒申鐃緒申鐃獣てわ申鐃緒申里如鐃緒申鐃緒申未鐃�Array鐃夙わ申鐃銃わ申箸鐃緒申泙鐃緒申鐃緒申辰鐃�promise鐃緒申鐃淑わ申鐃緒申鐃塾随申鐃緒申鐃書いわ申Array鐃夙ほわ申同鐃緒申鐃塾はわ申鐃緒申Array鐃夙違う鐃塾は￥申Out of Bounds鐃塾常申鐃�undefined鐃緒申鐃瞬わ申鐃緒申鐃緒申鐃�exception鐃祝なるこ鐃夙￥申
    • 

  • 鐃緒申鐃塾とわ申鐃緒申鐃駿縁申螢刻申箸鐃緒申鐃緒申鐃緒申鐃緒申里鐃宿�鐃竣なメソ鐃獣ドわ申鐃緒申鐃緒申鐃緒申泙鐃緒申鐃�
    • 

  • 鐃緒申鐃緒申鐃緒申鐃所、map鐃緒申filter鐃緒申鐃駿縁申評鐃緒申鐃緒申鐃銃わ申鐃殉わ申鐃緒申
    • 

  • 余鐃縮でわ申鐃緒申鐃緒申rakudo鐃叔もこ鐃塾ワ申戰鐃緒申鐃駿縁申評鐃緒申鐃緒申達鐃緒申鐃緒申鐃緒申討鐃緒申泙鐃緒申鐃�

    > [0..Inf].grep({$^x % 2 == 0}).map({$^x+1})[10]
21

    

    • 






Enjoy!


Dan the Lazy Evaluator