From: Kristof Bastiaensen <kristof@...>
Date: 2004-04-09T10:34:15+09:00
Subject: Re: why yield does not set $_  ?

On Fri, 19 Mar 2004 13:40:45 +0100, gabriele renzi @ google wrote:

> Hi,
> 
> Probably I just need to sleep, but I wonder: why $_ from yield? It would
> be useful for iterators' loops.
> 
> I'd expect this to work:
> file.each { gsub /a/,'b'}
> (using Kernel#gsub)
> 
> but it does not. Are there performance reasons or something else for
> this?
> 
> 
> Notice that, in general, I don't like $_ and hope it disappears, but
> while it is still there I'm someway seduced from it..
> 
> PS <not_so_semiserious>
> On this line, it would be even interesting to default every method
> called withouth a receiver to $_
> 
> [1,2,3].map { .+ 1} #=> [2,3,4]
> 
> We could even kill Kernel::gsub, ::split and the likes as we can achieve
> similar result with just a '.' more..
> 
> or:
> [1,2,3].any? { .==1}
> 
> BTW, I suppose ruby would become perl this way.. </not_so_semiserious>

Hello,
as far as I know, $_ has nothing to do with method invocation.
$_ gets only set after using gets or readline to the line read.
Maybe you are confusing with perl?
Kernel::gsub makes indeed use of $_, as a special case.
In the case of
  file.each { gsub /a/,'b'}
$_ will not be set, that's why this will not work.

Greetings,
Kristof