How to match paired closing bracket with regex

Question

My current regex matches a function name and the variable name passed to the function see here

Regex - (file_exists|is_file)\(([^)]+)
string if (is_file($file)){
Matches is_file and $file

I would also like the regex to work with a string rather than just a variable name, This includes strings with multiple opening and closing brackets.

Here's an extreme example.

Regex - (file_exists|is_file)\(????????)
string if (is_file(str_replace(array('olddir'), array('newdir'), strtolower($file))){
Matches is_file and str_replace(array('olddir'), array('newdir'), strtolower($file)

Is there a way to match the next closing bracket, unless one has been opened?

I would like to get it working at regex101

So, you need a regex for PHP? Note that there is no `str_replace(array('olddir'), array('newdir'), strtolower($file)` inside `if (is_file(str_replace(array(), array(), strtolower($file))){`. — Wiktor Stribiżew, Apr 01 '16 at 13:16
@WiktorStribiżew thanks, that was a last minute edit. i'm using vqmod which does a find and replace for php files. — TarranJones, Apr 01 '16 at 13:20
Looks like PHP: try [`'~(file_exists|is_file)($((?>[^()]++|(?2))*)$)~'`](https://regex101.com/r/eF9bK5/1) — Wiktor Stribiżew, Apr 01 '16 at 13:27
@WiktorStribiżew that seams to work brilliantly. thanks you. please leave an answer so i can accept it. — TarranJones, Apr 01 '16 at 13:30

score 2 · Accepted Answer · answered Apr 01 '16 at 13:30

You can use a regex with a subroutine call in PHP:

'~(file_exists|is_file)(\(((?>[^()]++|(?2))*)\))~'

See the regex demo

The pattern matches:

(file_exists|is_file) - one of the two alternatives
($((?>[^()]++|(?2))*)$) - Group 1 matching paired nested (...) substrings, and ((?>[^()]++|(?2))*) is Group 3 capturing the contents inside the outer paired (...).

Thus, the results are:

Group 1: is_file
Group 2: (str_replace(array(), array(), strtolower($file)))
Group 3: str_replace(array(), array(), strtolower($file))

Use Group 1 and 3.

How to match paired closing bracket with regex

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