Please fix this Regex for nested tags

I'm trying to nest tags with regex.

It's a "for" loop. This is the code I have so far:

<?php 
$test = "{for:a in b}
For1
{for:c in d}
For2
{/for}
{for:e in f}
Nothing
{/for}
{/for}";

$pattern = '#\{for:(.*)\sin\s(.*)}((?:[^{]|\{(?!/?for})|(?R))+)\{/for}#ms';
preg_match_all($pattern, $test, $matches);
print_r($matches);
 ?>

PHP:

The problem is that when I add any attributes to the "for" tag, the regex stops working. So I have {for:a in b} right now, but, if I remove everything so it reads just {for}, it will work. For example, this works:

This code is WORKING:

<?php 
$test = "{for}
For1
{for}
For2
{/for}
{for}
Nothing
{/for}
{/for}";

$pattern = '#\{for}((?:[^{]|\{(?!/?for})|(?R))+)\{/for}#';

preg_match_all($pattern, $test, $matches);
print_r($matches);
 ?>

PHP:

Can anyone help? It would be best if you can provide an explanation to why your fix works and mine doesn't, but it's not necessary, I just need the code/fix.

Thanks.

 

refrain greedy search.
use (.*?)
in
'#\{for.*)\sin\s(.*)}...........