TalkPHP - View Single Post

xenon · 12-12-2007, 10:38 AM

One more thing, though. How about recursivity in a regex rule? How does that work? I'm trying to make a simple BB code parser (just playing around), and something doesn't add up. Example:

Code:

/\[(b|i|u)(?:.+?)?\](.+?)\[\/\1\]/

would successfully match:

Code:

[b ]some text[/b ]

,

(without the spaces of course), but the following expression...

Code:

[b ]some [i ]text[/i ][/b ]

would leave me with:

Code:

some text[/i ]

That's when recursivity popped in my mind and I did a Google search. But I believe I don't use properly, or the back-references don't remain the same during a recursive operation, because this rule:

Code:

/\[(((b|i|u)(?:.+?)?)|(?R))\](.+?)\[\/\1\]/

, applied on the text introduced at the top, leaves me with:

Code:

some [i ]text[/i ]

Spooky

12-12-2007, 10:38 AM	#7 (permalink)
xenon The Frequenter Join Date: Dec 2007 Location: Bucharest, Romania Posts: 438 Thanks: 3	One more thing, though. How about recursivity in a regex rule? How does that work? I'm trying to make a simple BB code parser (just playing around), and something doesn't add up. Example: Code: /\[(b\|i\|u)(?:.+?)?\](.+?)\[\/\1\]/ would successfully match: Code: [b ]some text[/b ] , (without the spaces of course), but the following expression... Code: [b ]some [i ]text[/i ][/b ] would leave me with: Code: some text[/i ] That's when recursivity popped in my mind and I did a Google search. But I believe I don't use properly, or the back-references don't remain the same during a recursive operation, because this rule: Code: /\[(((b\|i\|u)(?:.+?)?)\|(?R))\](.+?)\[\/\1\]/ , applied on the text introduced at the top, leaves me with: Code: some [i ]text[/i ] Spooky __________________ I have optimistic thoughts, even though sometimes (if not always) life's a bitch.