From: Rob Biedenharn <Rob@...>
Date: 2008-04-20T04:29:35+09:00
Subject: Re: line breaks in multiline regexp

Oops!  If I have the "signed" option in Mail.app, the response doesn't  
make it sometimes.
-Rob

On Apr 18, 2008, at 9:25 AM, Andrey Chaschev wrote:

> Hi! I really want to know how to denote line breaks in multiline  
> regexp.
>
> The problem is that \s is not only a line break.
>
> I.e. how to parse this in a general way?
>
> s=<<HERE
> a  loooong-loooong text with
> MANY    spaces and *single* line breaks
> followed by three empty lines
>
>
> this line must be detached from the previous
> HERE
>
> Thanks in advance!

Just use \n to match the literal newline.  The m option just changes  
when \n is matched by a wildcard.

irb> s.match(/(.*\n\n\n)/m).captures
=> ["a  loooong-loooong text with\nMANY    spaces and *single* line  
breaks\nfollowed by three empty lines\n\n\n"]
irb> s =~ /(.*\n\n\n)/m
=> 0
irb> $1
=> "a  loooong-loooong text with\nMANY    spaces and *single* line  
breaks\nfollowed by three empty lines\n\n\n"

Without the m

irb> s =~ /(.*\n\n\n)/
=> 69
irb> $1
=> "followed by three empty lines\n\n\n"

You can still have \n, but the .* doesn't match all the previous  
characters.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com