Zugg Software :: View topic - [2.04] Can't use pipes (|) within {braces} in trigger pattern to match nothing

Wizard Joined: 14 Aug 2004 Posts: 1269

This is a new bug in v2.04.

I've reduced the trigger pattern to:
you ({|asking |exclaiming })

"you asking " matches but "you " does not. This feature (matching nothing) is very useful to capture optional text for #SUBs.

Win XP SP2

Apprentice Joined: 12 Jul 2004 Posts: 190 Location: Canada

If you write it in regex you can do it, I think... try:

you ({asking|exclaiming}?)

With the regular expression box checked.

Wizard Joined: 14 Aug 2004 Posts: 1269

Well, the point of beta testing is to find bugs not workarounds! Wink

But I might give it a go anyway.

Apprentice Joined: 12 Jul 2004 Posts: 190 Location: Canada

Aye, this I know... but I figured it wouldn't hurt to offer a tangible solution as well :)

Wizard Joined: 14 Aug 2004 Posts: 1269

Ah, I've found the actual bug: CMUD is generating the incorrect regular expression. It's not adding the | at the end:

CMUD v2.03:
you (asking |exclaiming |)
CMUD v2.04:
you (asking |exclaiming )

This is from the Test Pattern tab, where you can see the perl regex it is actually using.

Posted: Sat Sep 29, 2007 6:51 pm

Optional text and wildcards inside {these|things} are normally the two tipping points where I use a regex instead of a normal trigger. Thinjon's almost right - the proper regex is (asking|exclaiming)?.

Wizard Joined: 14 Aug 2004 Posts: 1269

Is (asking |exclaiming )? more efficient then (asking |exclaiming |)?

Note that words are usually followed by spaces, and always in this case, so I have to match a space too when there is a word there.

Apprentice Joined: 12 Jul 2004 Posts: 190 Location: Canada

My apologies, Fang... forgot my parenthesis-brace discrimination... I always do that. :P

In your case, Seb, I'd recommend:
you\s((asking|exclaiming)\s)?

Unless I've slipped on my syntax again, this should read "capture the word 'asking' or 'exclaiming' followed by a single space, or nothing at all, after the word 'you' followed by a space.

There MAY be a necessity for a non-capture syntax in there, I'm not certain... but in that case I think it'd be:
you\s((?:asking|exclaiming)\s)?

Posted: Sat Sep 29, 2007 7:03 pm

There's probably not a great deal of difference, since the regex moves from left to right through the possible options until one matches. The last one there matches (because it's empty), but the regex still has to go through the possibilities first. In the other one, the regex tries all the possibilities, but if none match, it carries on anyway.

I just hate how (some|thing|) looks - like you made a typo or missed an option out - especially when there's only one optional string.

Posted: Mon Oct 01, 2007 5:52 pm

bug confirmed and added to bug list