Дублировать сниппет php

<?php
function StrCharPosBack($haystack, $needle) {
    for ($i = strlen($haystack) ; $i>=0 ; $i--){
        if (substr($haystack, $i, 1) === $needle)
            return $i;
    }
    return false;
}

while (strpos($str, "{") !== false){
    $pos1 = strpos($str, "}");
    $buf_mas = substr($str, 0, $pos1);
    $pos2 = StrCharPosBack ($buf_mas, "{");
    $buf_mas = substr($buf_mas, $pos2+1);
    $exploded_buf_mas = explode ("|", $buf_mas);
    $rnd = rand(0, count($exploded_buf_mas)-1);
    $str = substr_replace($str, $exploded_buf_mas[$rnd], $pos2, $pos1+1-$pos2);
}

$str = (isset($str )) ? $str : '';
return $str ;

[[!str? &str= {
текст| 
текст2|
текст3|
тест4
}
]]