From: Michael Neumann <mneumann@...>
Date: 2005-02-23T03:54:16+09:00
Subject: Re: Proposal for nil, 0, and "" in an if statement

Brian Mitchell wrote:
> On Wed, 23 Feb 2005 03:00:03 +0900, Michael Neumann <mneumann@ntecs.de> wrote:
> 
>>Caio Tiago Oliveira wrote:
>>
>>>Michael Neumann, 22/2/2005 11:25:
>>>
>>>>100% agree. I especially cannot understand (at least mathematically)
>>>>why 0 would be empty and 1 not.
>>>>(...)
>>>
>>>
>>>Binary logic, 0 is false, 1 is true.
>>
>>In fact, those are actual symbols and not numbers!
> 
> 
> exactly! This issue seems to come up on the ML from time to time. I
> voiced my opinion that Smalltalk conditionals (depending on behavior)
> are much better than depending on value (check for nil or false). It
> can be tailored to fit any object easily... but I think the idea lost
> out to people who would rather keep ruby more of that same and
> probably a little faster (though there are some things ruby can't do
> because of this). My vote is still up for .true?  {} and .false? {}
> 
> ;-)
> 
> I really don't care if you guys agree or not but it sure is elegant.
> Ruby is already a very good language so I am happy anyhow.

At least for .nil? I agree. I am not sure whether I'd like to write
"if a.true?" all the time. Nevertheless I believe that

   if a.false?

is clearer to read and understand than:

   if not a

Just because human mind if very bad at negating conditions (proven by 
studies of some psychologists).

Regards,

   Michael