PHP call_user_func vs. just calling function

Question

I\'m sure there\'s a very easy explanation for this. What is the difference between this:

function barber($type){
    echo \"You wanted a $type haircut, no         


        

Answer 1

in your first example you're using function name which is a string. it might come from outside or be determined on the fly. that is, you don't know what function will need to be run at the moment of the code creation.

Answer 2

There is no benefits calling the function like that because I think it mainly used to call "user" function (like plugin) because editing core file is not good option. here are dirty example used by Wordpress

<?php
/* 
* my_plugin.php
*/

function myLocation($content){
  return str_replace('@', 'world', $content);
}

function myName($content){
  return $content."Tasikmalaya";
}

add_filter('the_content', 'myLocation');
add_filter('the_content', 'myName');

?>

...

<?php
/*
* core.php
* read only
*/

$content = "hello @ my name is ";
$listFunc = array();

// store user function to array (in my_plugin.php)
function add_filter($fName, $funct)
{
  $listFunc[$fName]= $funct;
}

// execute list user defined function
function apply_filter($funct, $content)
{
  global $listFunc;

  if(isset($listFunc))
  {
    foreach($listFunc as $key => $value)
    {
      if($key == $funct)
      {
        $content = call_user_func($listFunc[$key], $content);
      }
    }
  }
  return $content;
}

function the_content()
{
  $content = apply_filter('the_content', $content);
  echo $content;
}

?>

....

<?php
require_once("core.php");
require_once("my_plugin.php");

the_content(); // hello world my name is Tasikmalaya
?>

output

hello world my name is Tasikmalaya