Preg_replace_callback function Solution

Preg_replace_callback function

$val = Preg_replace ("/\[([^\[\]]*) \]/eis", "'. '). Str_replace (' $ ', ' \$ ', ' \\1 ') ", $val);

This sentence with the Preg_replace_callback function how to rewrite it to ask for advice under
------Solution--------------------

$val = Preg_replace_callback ("/\[([^\[\]]*) \]/eis", function ($match) {return str_replace (' $ ', ' \$ ', $match)}, $val);

------Solution--------------------

$val = Preg_replace_callback (
        '/\[([^\[\]]*) \]/is ',
        function ($matches) {
            Return '. '. Str_replace (' $ ', ' \$ ', $matches [1]);
        },
        $val
    );
Echo $val;

------Solution--------------------
References:

the last place in the middle of the code include which line is not clear how to change

$pattern = '/
   
     . *?
   
     /s ';
$replacement = "' {include file= '. Strtolower (' \\1 '). '} ';
$source = Preg_replace_callback ($pattern, $replacement, $source);

- -

Still the same is a string ah or the original way to do it
------Solution--------------------
$replacement = function ($matches) {return ' {include file= '. Strtolower ($matches [1]). '}';};

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