From: Robert Klemme <bob.news@...>
Date: 2004-08-27T19:40:41+09:00
Subject: Re: Strange behaviour regarding lexical scopes?


"Michal" <lists+rubytalk@box.cz> schrieb im Newsbeitrag
news:20040827095945.GB26572@box.cz...
> Hello,
>
> today (when explaining bits of Ruby to my friend)
> I got confused by this:
>
> $ cat a.rb
> b = 4
> if b == 1
>     a = 1
> end
> p a
>
> $ ./a.rb
> nil
>
> $ ruby --version
> ruby 1.8.2 (2004-07-29) [i686-linux]
>
> (latest gentoo ebuild)
>
> Why is it that 'a' is nil and not undefined? (i would expect:
>
> undefined local variable or method `a' for main:Object (NameError)
>
> )
>
> Thanks in advance,
>                       M.

"if" doesn't introduce a new scope, similar to "switch" in C et. al.  So "a"
and "b" reside really in the same scope and the definition in the true
clause is sufficient to make "a" defined.  The assignment need not be
executed.

Kind regards

    robert