From: Marnen Laibow-Koser <marnen@...>
Date: 2009-12-07T00:33:49+09:00
Subject: Re: Regexp.escape with un-escapes

Thomas Sawyer wrote:
> Hi--
> 
> I want to translate a string into a regular expression, but I want to
> "un-escape" portions as raw regexp. For example:
> 
>   "here is a setting 'a' equal to ((\d+))"
> 
> So I want to Regexp.escape the string, before I pass it to Regexp.new,
> but I want what's in the (( )) to stay exactly the same with the
> double-parens removed.
> 
> I know that has to be a fairly concise way to do this, but all I've
> come up with is some very ugly brute force code that iterates back and
> forth using index '((' and index '))'.
> 
> Any suggestions?

Why, yes!  Use a regexp to find the (( )) bits, and then extract them, 
don't escape them, and paste the whole regexp together.  It's a bit 
ironic to me that in a regexp-handling routine, you're doing brute-force 
index searches. :)

Best,
-- 
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
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