javascript - How to make use of recursion in preg_replace_callback -

i have javascript function (not plain javascript)

function formatstring () {     var args = jquery.makearray(arguments).reverse();     var str = args.pop();      return str.replace(/{\d\d*}/g, function () {        return args.pop();     });  } 

that use format string e.g formatstring("{0} , {1}", "first", "second"); returns "first , second"

i want replicate same functionality in php , have following function:

function formatstring() {    if(func_num_args() > 1) {       $args = array_reverse(func_get_args());       $input = array_pop($args);    }    return preg_replace_callback('/{\d\d*}/', function() use ($args) {       return array_pop($args);    }, $input); } 

however, in case formatstring("{0} , {1}", "first", "second"); returns "first , first"

unlike javascript version of function callback executes every match, php variation seems execute callback once.

i considering making recursive call formatstring callback since preg_replace_callback calls callback own arguments (here in array of matches) having challenge recursion.

please advise on how best utilize callback or alternative solution using preg_replace_callback. use of global variables out of question.

your problem: php pass-by-value. consider this:

function pop_it($array) {   array_pop($array);   print_r($array); }  $array = array(1, 2); print_r($array); // => array([0] => 1, [1] => 2)  pop_it($array); // => array([0] => 1)  print_r($array); // => array([0] => 1, [1] => 2) 

your function called fine. same argument, since $args never changes. not matters - outside callback. need pass-by-reference make change stick.

change function pop_it(&$array) (or use (&$args)), and... happens.

however, not approach, wrong thing formatstring("{1} , {0}", "second", "first"), formatstring("{0} , {0}", "only"). i'd pluck index out regexp , find in array. (also, \d\d* less legible than, equivalent to, \d+.)