From: Devin Mullins <twifkak@...>
Date: 2006-10-08T22:36:57+09:00
Subject: Re: nil being empty

Hal Fulton wrote:
> I think/hope we all know that. The point is that there are times
> when it feels natural to say:  if x.empty?
> 
> But circumstances force us to say: if x.nil? || x.empty?
> or the equivalent.
Io has a neat idiom for things like this. Whereas a normal message pass is:
   size := list size
If you do:
   size := list ?size
That's equivalent to:
   size := if(list, list size, nil) // that is, if/then/else
What's nice is you can chain it:
   size := animal ?limbs ?size
But in this situation, you could create a List isNotEmpty method and:
   x ?isNotEmpty ifFalse(...)
Or something.

Devin