配列足し算いろいろ
普通に for
Array.prototype.sum_for = function() { var r = 0; for(var i = 0, l = this.length; i < l; i++) { r += this[i]; } return r; }
while pop
Array.prototype.sum_while = function() { var r = 0; var f; while(f = this.pop()) { r += f; } return r; }
join eval
Array.prototype.sum_eval = function() { return eval(this.join('+')); }
pop 再帰
Array.prototype.sum_ref = function() { if(this.length == 1) return this[0]; return this.pop() + arguments.callee.apply(this); }
普通に for が一番速いです。