From: Bertram Scharpf <lists@...>
Date: 2007-08-23T21:32:11+09:00
Subject: Re: Renaming Files

Hi,

Am Donnerstag, 23. Aug 2007, 20:29:26 +0900 schrieb Stefano Crocco:
> Alle gioved� 23 agosto 2007, Gabriel Dragffy ha scritto:
> > irb(main):043:1> File.move( f, f.gsub!( /\s/, '_' ) )
> 
> You need gsub, not gsub!. [...] gsub, instead, creates a new string and 
> modifies it, so File.move receives two different strings.

I suppose the evaluation order of arguments is left to right
and f is handed over to File#move as long as it is the old
version. Yet, before is gets used it becomes modified by its
gsub! method.

Independently from such considerations it is never a good
idea to rely on evaluation orders anywhere else than in
and/&&/or/|| expressions. If File#move were a method taking
a block it surely were no good programming style either to
modify f inside that:

  some_method( f) do ... ; f.gsub! ... ; ... end

This is admittedly not a beginners topic and probably far
from what Gabriel expected to meet.

Bertram


-- 
Bertram Scharpf
Stuttgart, Deutschland/Germany
http://www.bertram-scharpf.de