<?php function map($fun, $list,$params=array()){     $acc=NULL;     $last=array_push($params, NULL,$acc)-1;     foreach($list as $params[$last-1]){     //第一次见这种写法感觉很神奇         $params[$last]=call_user_func_array($fun , $params  );     }     $acc=array_pop($params);     return $acc; } function add($element,$acc){     if ($acc == NULL);     return $acc=$element+$acc; } $result=0; $result=addTo($result,1); $result=addTo($result,2); $result=addTo($result,3); echo "result = $result\n"; $result=0; $result=map('addTo',array(1,2,3)); echo "result= $result\n"; ?>