From: Bertram Scharpf <lists@...>
Date: 2009-12-10T21:18:43+09:00
Subject: Re: which is better?

Hi,

Am Donnerstag, 10. Dez 2009, 18:58:04 +0900 schrieb Robert Klemme:
> 2009/12/10 Wybo Dekker <wybo@servalys.nl>:
> >
> > But why no parentheses?:
> > irb
> >>> $-w=true
> > => true
> >>> "abcd1234".gsub! /\d+/,''
> > (irb):13: warning: ambiguous first argument; put parentheses or even spaces
> > => "abcd"
> >>> "123ab".tr! "0-9",""
> > => "ab"
> >
> > what is the ambiguity in the first case, and why is there no warning in the
> > second case?
> 
> Seems to be related to the regexp:
> 
> 10:56:19 $ ruby19 -wce 'o.gsub! /\d/, ""'
> -e:1: warning: ambiguous first argument; put parentheses or even spaces
> Syntax OK
> 10:56:42 $ ruby19 -wce 'o.gsub! "d", ""'
> Syntax OK
> 10:56:50 $ ruby19 -wce 'o.gsub!(/\d/, "")'
> Syntax OK
> 10:57:01 $
> 
> Why? No idea.

The slash could also be a division operator. Say:

  $ ruby -wce 'o.gsub! %r/\d/, ""'
  $ ruby -wce 'o.gsub! %r{\d}, ""'

Bertram


-- 
Bertram Scharpf
Stuttgart, Deutschland/Germany
*
Discover String#notempty? at <http://raa.ruby-lang.org/project/step>.