From: Brian Candler <B.Candler@...>
Date: 2007-03-11T03:12:24+09:00
Subject: Re: A couple of questions from a Ruby neophyte

On Sun, Mar 11, 2007 at 02:32:13AM +0900, M. Edward (Ed) Borasky wrote:
> This is probably a FAQ, but just how different *are* Perl and Ruby regex 
> capabilities? I'm not a heavy regex user by any stretch of the 
> imagination. I do the basic stuff that will work anywhere (original 
> "vi", "grep", "sed", "awk") so Perl and Ruby are overkill for me.

I don't know if all the differences are documented anywhere, but the one
which bit me was that ^ and $ do not match only start and end of string, but
also start and end of line within a string.

So if you want to safely validate an entire string against a pattern, use
     /\A...\z/ 
not
     /^...$/

The regexp modifiers are different too. If I remember rightly, Ruby /../
acts like Perl /../m. And if you write /../m in Ruby, it's like Perl /../ms

(or it could be the other way round :-)

Regards,

Brian.