From: Marnen Laibow-Koser <marnen@...>
Date: 2010-01-14T05:22:29+09:00
Subject: Re: Ruby Regex

Xavier Noria wrote:
> String literals have a one-pass escaping at parse time, so that
> 
>     "foo\\bar\nbaz"
> 
> is an encoded way to express
> 
>     foo\bar
>     baz
> 
> And the result of that ordinary pass is what gsub receives.
> 
> Then, at runtime gsub inspects its argument and looks in turn for
> occurrences of \1, \& and friends. That is gsub's contract, and has no
> relationship with string literals parsing.
> 
> You need double-scaping for \1 and friends to skip both passes, one
> related to literals, and the other one related to how gsub works.

Yes, I see that now.  I wasn't aware that gsub did an extra parsing 
step.  With that in mind, doubling backslashes makes sense.

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