Re^3: Simple regex question. Grouping with a negative lookahead assertion.

[kcott]

"... the modifiers xms ... would be better as:"

Well, I've seen some things taken out of context in my time but I think this one takes the biscuit. I'm not annoyed; I actually got a bit of a chuckle. I was, however, somewhat surprised.

Just so we're clear, let me highlight the seven words you pulled out of three sentences in order to get something to quibble about:

"I note that the modifiers xms are written in the same (alphabetically) unordered way as they appear throughout Perl Best Practices (PBP). So, either you've just copied those from somewhere else and don't know what they mean (see perlre - Modifiers) or you're required to follow PBP. If the latter, you should use warnings (see also -w in perlrun) and the regular expression would be better as:

My regex following "You can clean that up by ..." was:

/atg(.+?)(?:taa|tag|tga)/

That was my solution. I was happy with it. I'm still happy with it.

I then went on to say that if the OP was "required to follow PBP" then certain other things should be done. These included using warnings and making some changes to my regex. I wasn't advocating blind adherence to PBP and I don't believe anything in my post suggested that.

As far as the order of the modifiers goes: write them any way you want. PBP typically has xms (and, yes, that's the order in which they are presented in the book); I prefer to write them alphabetically (that's just me); to the best of my knowledge, the regex engine doesn't care what order you use.

Regarding the (?>pattern) construct, I claimed no advantage to using this. It's just another PBP guideline: "... rewrite any instance of: X | Y as: (?> X | Y )" [truncated extract from page 271].

Finally, you make a good point about "lower- (or canonical-) casing". I concur.

[AnomalousMonk]

I apologize for my confusion, but at least I was able to brighten your day with a chuckle!