PHP/Regex: simple regex for bbcode [s] or [strike] fails to work

Question

For a silly bbcode parser I wanted to add two definitions into one, my original definition was this for preg_replace:

\'#\\[s\\](.*?)\\[/s\\]#si\', \'

        

Answer 1

The problem is that you added two new regex groups, (s|strike) in the opening tag and (s|strike) in the closing tag. So inside your resulting code you will get s or strike. You can fix that by simply using the correct group number, 2.

Another way would be to make that new groups non-referencing, by adding a ?: to the beginning, but I guess the first solution is easier to understand:

#\[(?:s|strike)\](.*?)\[/(?:s|strike)\]#si