From: dblack@...
Date: 2002-09-20T10:11:30+09:00
Subject: Re: Thoughts on improving usage of Regexp#match

Hi --

On Fri, 20 Sep 2002, Hal E. Fulton wrote:

> Please feel free to point out obvious things
> that I'm not seeing here.
>
> I was looking at a piece of code like this:
>
>   sub1 = ""
>   if str =~ regex
>     sub1 = $1
>   end
>
> and I thought three things:
>   1. I've never liked the $1 -- I usually avoid
>      Perlish variables, even the common ones.
>   2. I don't like the if.
>   3. I don't like having to assign sub1 twice.
>
> So I tried writing:
>
>   sub1 = regex.match(str)[1] || ""
>
> In theory this should be the same as the other
> four lines of code.
>
> But it doesn't work because if the match
> fails, #match returns nil and I can't call
> [] on nil.

You could do:

  sub1 = regex.match(str).to_a[1].to_s


> So I thought: Why don't I make a special
> MatchData object that will just return nil
> for any [] call?
[...]
> Thoughts?

Would you have to test the [0] element to see whether the match had
succeeded?


David

-- 
David Alan Black                      | Register for RubyConf 2002!
home: dblack@candle.superlink.net     | November 1-3
work: blackdav@shu.edu                | Seattle, WA, USA
Web:  http://pirate.shu.edu/~blackdav | http://www.rubyconf.com