From: mike@... (Mike Stok)
Date: 2003-07-11T03:00:40+09:00
Subject: Re: Ruby T-Shirt Idea

In article <035a01c346a5$7740f600$0300a8c0@austin.rr.com>,
Hal E. Fulton <hal9000@hypermetrics.com> wrote:

[...]

>BTW, var = Regexp.new(Regexp.escape(var)) will
>also do that conversion... probably more than
>two ways... ;)
>
>As for interpolating a variable into a regex,
>I'm not sure whether it does automatic escaping
>or not. I'd like to think it does, but there 
>may be some good reason it doesn't. Too lazy to
>test right now...

It doesn't automatically escape the interpolated thing and that's a good
thing.  Sometimes I construct alternations dynamically e.g.

[mike@ratdog mike]$ irb --simple-prompt
>> words = %w{foo bar baz}
=> ["foo", "bar", "baz"]
>> match_a_word = /\b(?:#{words.join('|')})\b/
=> /\b(?:foo|bar|baz)\b/
>> "April fool" =~ match_a_word
=> nil
>> "this has a foo in it" =~ match_a_word
=> 11

and I don't want the interpolation to quietly "save me from myself."  Of
course it's my responsibility to escape things which need escaping.

Sometimes I do miss a perl-like \Q in an interpolated string, but the
power of #{ ... } more than makes up for it.

Mike

-- 
mike@stok.co.uk                    |           The "`Stok' disclaimers" apply.
http://www.stok.co.uk/~mike/       | GPG PGP Key      1024D/059913DA 
mike@exegenix.com                  | Fingerprint      0570 71CD 6790 7C28 3D60
http://www.exegenix.com/           |                  75D2 9EC4 C1C0 0599 13DA