From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2008-11-19T20:28:18+09:00
Subject: Re: RegExp problem

On Wed, Nov 19, 2008 at 11:58 AM, Florian Gilcher <flo@andersground.net> wrote:
> Actually the correct regexp is:
>
> delimiter = Regexp.escape(delimiter)
> /#{delimiter}[^#{delimiter}]*#{delimiter}/
>
> Read: The delimiter - an unspecified number of non-delimiter-characters -
> the delimiter.
>
> Otherwise, you too heavily rely on the behaviour of the library, when it
> coms to the dot.

Hi Florian,

I don't get what you mean by "too heavily rely", I mean, you are
always relying on the behaviour of the regexp library when it comes to
everything, so if you know how the dot, the * and the ? work in Ruby
why is your regexp better than the proposed one?

Anyway I have realized I had a mistake in my regexp (I had the ?
outside of the group, and not next to the *). So fixing that:

irb(main):034:0> string="rzerze@foo@rezrzgrtez"
=> "rzerze@foo@rezrzgrtez"
irb(main):035:0> re = Regexp.new("([#{delimiter}])(.*?)\\1")
=> /([abcde])(.*?)\1/
irb(main):036:0> string.match(re)[2]
=> "rz"

Now works as I intended. With your version:

irb(main):037:0> re = /([#{delimiter}])([^#{delimiter}]*)\1/
=> /([abcde])([^abcde]*)\1/
irb(main):038:0> string.match(re)[2]
=> "rz"

works too. So I would like to know why would be one preferred over the other.

Jesus.