From: "David A. Black" <dblack@...>
Date: 2010-08-07T23:08:02+09:00
Subject: Re: regexp help - substring of a backreference

Hi --

On Sat, 7 Aug 2010, Bryan Kennerley wrote:

> I'm putting together a web forum and want to parse web addresses that
> are part of messages into clickable links. This is my attempt, I'm not
> claiming its perfect but it works:
>
> text.gsub!(/http:?\/*(\w+[\w\-\.\/~\?%&=#;,\+:\@]+)/,
>          ' <a href="http://\1" target="_blank">http://\1</a>')
>
> The problem is that some web addresses are incredibly long, so I want
> the link text to be limited to, say, 50 chars. i.e. the second \1 needs
> to be \1[0..49] or something. I can't figure out any easy way of doing
> it, any ideas?

You can use the block form, plus the thread-local $ variables:

   text = "a bunch of miscellaneous words"
   text.gsub!(/a b(.+)/) { $1[0,10] }
   puts text  # unch of mi


David

-- 
David A. Black, Senior Developer, Cyrus Innovation Inc.

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