From: "John W. Long" <ng@...>
Date: 2006-05-25T00:13:41+09:00
Subject: RegExp Problem

Hi,

I'm having a little trouble getting Ruby to match quotes correctly. 
Suppose I wanted to extract any quoted string followed by an exclamation 
point. I'd like my regular expression match either single or double 
quotes. I thought the following might work:

   re = /(['"])([^\1]*?)\1!/
   md = re.match %{ "this looks like "fun"!" }
   md[0] #=> "\"this looks like \"fun\"!"

But as you can see instead of matching <"fun"!> it matched <"this looks 
like "fun"!>, despite the fact that I've told it to match anything but 
the character that was used to quote it:

   [^\1]*?

It works beautifully if I tell it to match either single quotes or 
double quotes, but I can't write it to match either in a single regular 
expression:

   re = /"([^"]*?)"!/
   md = re.match %{ "this looks like "fun"!" }
   md[0] #=> "\"fun\"!"

Or:

   re = /'([^']*?)'!/
   md = re.match %{ 'this looks like 'fun'!' }
   md[0] #=> "'fun'!"

Why does the first regex not do what I want?

--
John Long
http://wiseheartdesign.com
http://radiantcms.org