Can I use operators as function callback in PHP?

Question

Suppose I've the following function:

function mul()
{
   return array_reduce(func_get_args(), '*');
}

Is is possible to use the * operator as a callback function? Is there any other way?

Answer 1

In this specific case, use array_product():

function mul() {
  return array_product(func_get_args());
}

In the general case? No, you can't pass an operator as a callback to a function. You would at least have to wrap it in a function:

function mul() {
   return array_reduce(func_get_args(), 'mult', 1);
}

function mult($a, $b) {
  return $a * $b;
}

Answer 2

The code you have provided wouldn't work but you can do something similar.

function mul()
{
   return array_reduce(func_get_args(), create_function('$a,$b', 'return "$a * $b'));
}

create_function allows you to create short function (one liner), if your function is getting longer then one statement it's better to create a real function to do the job.

Please also note the single quote are important because you are using dollar symbol so you don't want PHP to try to replace them.