From: Dave Thomas <dave@...>
Date: 2003-05-24T13:42:38+09:00
Subject: Re: why is "does" missing from this sub!-stitution?

dblack@superlink.net wrote:

> I'm with you on the 'what', but I'm still curious about the 'why'.
> It's true that the replacement string gets parsed before sub is
> called.  But I think "abcdef" gets matched against the regex even
> before that parse happens.


But it doesn't. Think about it this way

   def fred(a, b)
     $x = 1
     puts a
     puts b
   end

   $x = 99
   fred(11, $x)
   fred(11, $x)

#=>
   11
   99
   11
   1

The parameters to a method are evaluated at the point of call: the 
method can't affect the value of its parameters.


   Which means... if the $1,$2 variables
> reflect the results of the most recent match, then one could argue
> that by the time the replacement string is parsed, a match has just
> taken place and $1,$2 should reflect the results of that match.

.sub is just a method, so it can't affect the value of its second parameter.


Cheers


Dave