From: Glen Holcomb <damnbigman@...>
Date: 2010-02-19T05:02:53+09:00
Subject: Re: Ruby conditionals subtlety?

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On Thu, Feb 18, 2010 at 12:49 PM, Farhad Farzaneh <ff@onebeat.com> wrote:

> Hi,
>
> Anyone know why thse two forms of "unless" behave differently?
>
> > irb
> irb(main):001:0> foo =3D true unless defined?(foo)
> =3D> nil
> irb(main):002:0> unless defined?(fooo) ; fooo =3D true ; end
> =3D> true
>
> thx
> --
> Posted via http://www.ruby-forum.com/.
>
>
From playing around it doesn't look like unless is "behaving differently"
Ruby has created a label for foo since it thinks it is going to be assignin=
g
it something (dynamic language)

For example

>> foo =3D true unless defined?(foo)
=3D> nil
>> unless defined?(fooo); fooo =3D true; end
=3D> true

>> foo
=3D> nil
>> fooo
=3D> true

>> foo =3D true unless defined?(foom)
=3D> true

>> foo
=3D> true

Basically it looks like foo appears to exist but it doesn't really exist ye=
t
so the first unless "acts" oddly.  This is very interesting though.  Perhap=
s
someone who knows what they are talking about can tell us why it appears to
behave this way.

--=20
"Hey brother Christian with your high and mighty errand, Your actions speak
so loud, I can=92t hear a word you=92re saying."

-Greg Graffin (Bad Religion)

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