preg_replace换成preg_replace_callback解决方法

preg_replace换成preg_replace_callback
function fetch_str($source){
$source = $this->smarty_prefilter_preCompile($source);
return preg_replace("/{([^\}\{\n]*)}/e", "\$this->select('\\1');", $source);
}
------解决思路----------------------

return preg_replace_callback("/{([^\}\{\n]*)}/", 
    function($m) {
      return $this->select($m[1]);
    }, $source);

分行写只是为了看得清楚