From: Brock Weaver <brockweaver@...>
Date: 2005-08-19T01:18:39+09:00
Subject: Re: unless statement... why oh why?

DeMorgan's theorem and operator precedence in ruby.

DeMorgan's theorem in a nutshell:

(Not A) and (Not B) == Not (A or B)

Your code is

(Not A) and (Not B) == (Not A) or (B)

See the difference?

On 8/18/05, Zach Dennis <zdennis@mktec.com> wrote:
> thr = Thread.new{}
> # thread dies
> 
> "HERE" if not thr or not thr.alive? # this works!!
> "HERE" unless thr or thr.alive? # doesn't work!! WHY?
> "HERE" unless thr and thr.alive? # works, but why?
> 
> I dont see why the unless/and works when the unless/or should be the one
> short-circuting no?
> 
> Thanks,
> 
> Zach
> 
> 


-- 
Brock Weaver
[OBC]Technique