From: Jamis Buck <jgb3@...>
Date: 2004-10-30T03:38:43+09:00
Subject: Re: Another scrach on head

Mohammad Khan wrote:
> On Fri, 2004-10-29 at 14:16, Mohammad Khan wrote:
> 
>>On Fri, 2004-10-29 at 14:05, Jamis Buck wrote:
>>
>>
>>>By definition (in Ruby), nil and false are false, and _everything else_ 
>>>is true. Its an axiom in Ruby. Just as, in C, 0 is false and all other 
>>>integers are true.
>>
>>Thanks, for clarify this. My appology, I didn't know that !
>>
>>--
>>Mohammad
>>
> 
> 
> Wait a minute,
> you are  trying to say, 
> nil and false are false.
> so we should have
> nil == false -> true

No, I mispoke for the sake of simplification. nil and false _evaluate to 
false_ in a boolean context, and everything else evaluates to _true_ in 
a boolean context.

Thus

   puts "here" if false
   puts "there" if nil

would print nothing, whereas

   puts "here" if true
   puts "there" if 5
   puts "everywhere" if 1 && Object.new && :foobar

would print

   here
   there
   everywhere

Hope that is clearer.

- Jamis

-- 
Jamis Buck
jgb3@email.byu.edu
http://www.jamisbuck.org/jamis