nested functions in php throws an exception when the outer is called more than once

Question

lest assume that i have the following

function a(){
  function b(){}
}
a(); //pass
a(); //error

why in the second call an exception is thr

Answer 1

This is because when you execute function a it declares function b. Executing it again it re-declares it. You can fix this by using function_exists function.

function a(){
  if(!function_exists('b')){
    function b(){}
  }
}

But what I suggest is, you should declare the function outside. NOT inside.