This does not work
$check["pattern"] = "/correct/";
$callback = "function ($m) { return ucfirst($m[0]);}";
echo preg_replace_callback($check["pattern"],$callback,"correct" );
output: correct
This works
$check["pattern"] = "/correct/";
echo preg_replace_callback($check["pattern"],function ($m) { return ucfirst($m[0]);},"correct" );
output: Correct
Why, and how to make it work with the function stored inside a var? :)
Why would you want to do that? I see no reason to store the function inside a variable, to be honest. Nevertheless, if you really want to do this, take a look at create_function:
<?php
$check["pattern"] = "/correct/";
$callback = create_function('$m', 'return ucfirst($m[0]);');
echo preg_replace_callback( $check['pattern'], $callback, "correct" );
// Output: "Correct"
If you do a var_dump on $callback = "function ($m) { return ucfirst($m[0]);}"; the result is a string. In the working situation you pass a Closure (anonymous function) as callback.
The manual is clear: a Closure is allowed, if you pass a string, it must be the name of a function.
