Zugg Software :: View topic - Regex can't detect a [ at the beginning of a line

Posted: Sat Feb 03, 2007 10:01 pm

Is there some problem with detecting a "[" at the beginning of a line? I tried the following without any success:

Regex:
^[

-Reed

Posted: Sat Feb 03, 2007 10:27 pm

[ is a special character, it needs escaping with \ to create:

Posted: Sun Feb 04, 2007 12:39 am

I must have made a typo, because I meant to type a "\" before the [. So I meant that even with escaping the character it didn't work... which I thought was odd.

Posted: Sun Feb 04, 2007 1:14 am

Okay, so it sounds like Fang is seeing the same issue that I am if I'm understanding his edit correctly. The issue being that even when the brace is escaped it doesn't fire.

Posted: Sun Feb 04, 2007 5:25 am

I did some playing around with this and it seems tied to an issue with the parser looking for a closing bracket.

I tested with these triggers.

#REGEX {Test} {#show A Works}
#REGEX {[Test]} {#show B works}
#REGEX {[Test} {#show C works}

#SHOW "[Test] this"
#SHOW "[Test this"
#SHOW "[Test this] as well"

The first show command will fire all 3 triggers, the second and third show commands will only fire the first trigger.

[Edit] The problem holds true even if its not at the beginning of a line.

Posted: Sun Feb 04, 2007 8:31 am

Well I'm glad this could be verified and that I wasn't doing something dumb to cause it.

Magician Joined: 17 Apr 2005 Posts: 496

Here, as well--having a single (quoted) [ anywhere failed, having matched []s or a single ] works fine.

Having a single unquoted [ was treated like there was an invisible closing (unquoted) ] at the end.

Posted: Mon Feb 05, 2007 8:12 pm

Tech: aren't you missing some \ characters in your #REGEX patterns? I know that the forum bbcode will convert \ [ into just [ so maybe that was the problem. I think if you put it within a [code] bbcode tag then it won't strip them.

In any case, the [ *is* a special regular expression character. It is used to specify character ranges. So you *must* put a \ character before the [ in your pattern for anything to make sense.

I'm assuming that you used the \ and it was just the forums that messed up the post, because when I tried your examples and had the correct \ in front of each [ then it still failed just as you mentioned. So I've added this to the bug list.

Posted: Tue Feb 06, 2007 12:40 am

Yes I did use the \ before the [. I didn't even notice that they got stripped.

Posted: Tue Feb 06, 2007 1:03 am

Ah, so I'm not going crazy, I did have it there and the forum stripped it without me noticing. I felt like an idiot when I looked back it wasn't escaped and I thought I had escaped it.

I did have a "\" before the "[" because I knew that braces are special characters for character ranges.