From: bbiker <renard@...>
Date: 2007-04-20T12:50:21+09:00
Subject: Re: Unless Expression Parsing

On Apr 19, 9:53 pm, Gary Wright <gwtm...@mac.com> wrote:
> I just came across an unexpected parsing problem:
>
> x = 3 unless true       # parses just fine, x = nil
>
> p(3 unless true)        # parser chokes on unless
>
> p((3 unless true))      # OK, 'nil' is printed
>
> This seems like a bug in the parser rather than a real
> syntax problem, but maybe I'm missing something?
>
> Gary Wright

in irb:

  x = 3 unless true      =>  nil

  x                             => nil       # x declared as a nil
object since it was never assigned an object
 p 3  unless  true        =>  nil

p (( 3 unless true))       => nil      #  you're asking for the result
of '3 unless true', )



p nil                         =>            # no result since p did
nothing

3 unless true            =>            # the result is nil but not
captured
so
p (3 unless true)       =>            # no result since you are asking
p to print nothing

Note:

the above is equivalent to
unless true                                 so 'p 3' never gets
interpreted and nothing happens
  p 3
end