From: Dave Thomas <dave@...>
Date: 2003-05-24T09:49:34+09:00
Subject: Re: why is "does" missing from this sub!-stitution?

dblack@superlink.net wrote:

> My first thought by way of explaining the $2 behavior was: there's
> been no assignment to $2, because the regex has been compiled but the
> match hasn't happened yet.  But then \2 wouldn't be meaningful....  So
> I do actually start to wonder why the previous $2 (nil or otherwise)
> persists so long.

\2 is substituted by .sub (ie, it gets passed in as part of the string, 
and .sub looks for and substitutes for it). #$2 is substituted during 
the initial parse of the string (before .sub is even called)

irb(main):008:0> "abcdef".sub(/(..)/, "#$1")
=> "cdef"
irb(main):009:0> "abcdef".sub(/(..)/, "#$1")
=> "abcdef"


Cheers


Dave