From: Oliver Andrich <oliver.andrich@...>
Date: 2005-12-07T08:07:35+09:00
Subject: Re: Question concerning multiline regexps and best practice

ako... schrieb:
> unless i do not understand the question, a regex option that allows
> multiline matches might be used.

Well, to better describe what I am currently dealing with, I post a 
snippet of python code with the regex.

msg_rx = re.compile(
     "^\x01?" +
     "(?P<srcid>[a-zA-Z]{3,4})(?P<msgnum>\\d{3,4}) " +
     "(?P<prio>\\d) " +
     "(?P<department>[a-zA-Z]{1,3}) " +
     "(?P<wordcnt>\\d{1,4}) " +
     "(?P<optional>.*)\r\n*" +
     "(?P<keywords>.*)\r\n*" +
     "\x02" +
     "(?:(?P<headline>.*)=\\s*\r\n)?" +
     "(?P<text>.*)" +
     "\x03.*" +
     "(?P<day>\\d{2})(?P<hour>\\d{2})(?P<minute>\\d{2}) " +
     "(?P<mon>[a-zA-Z]{3}) " +
     "(?P<year>\\d{2})",
     re.S
)

This little "baby" does the job. As ruby doesn't have named groups in 
regexps, I have to add comment lines (?#...) to document the invidual 
groups. This would glutter the thing even more. Now ruby has these nice 
HERE documents, %r{...} and so on. I would be happy if I could achieve 
something like that.

msg_rx = %r{
^\x01?
(?# comment for the line)
([a-zA-Z]{3,4})(?P<msgnum>\\d{3,4})\s
(\\d)\s
(?# comment for the line)
([a-zA-Z]{1,3})\s
(?# comment for the line)
(\\d{1,4})\s
(.*)\r\n*
(.*)\r\n*
\x02
(?# comment for the line)
(?:(.*)=\\s*\r\n)?
(?# comment for the line)
(.*)
\x03.*
(?# comment for the line)
(\\d{2})(\\d{2})(\\d{2})\s
(?# comment for the line)
([a-zA-Z]{3})\s
(?# comment for the line)
(\\d{2})
}

Thinks looks a lot cleaner for me, but sadly the "\n" at the end of the 
lines are in my way. :) I could strip them, but if it would just 
"happen" it would be nicer.

Hopefully, this makes my question a little clearer.

Best regards, Oliver