<?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";
?>