From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2005-11-17T23:47:20+09:00
Subject: Re: Object#to_b

Austin Ziegler wrote:
> I used to use "unless
> var.nil?" but it is easier to say:
> 
>   if var and var.foo
> 
> than:
> 
>   if (not var.nil?) and var.foo

`if var and var.foo' would still work. If `var' is undefined (nil), its 
#to_b method will return false. So unless var is an object that 
overrides the #to_b method, your code will still work.

I can see the problem with the performance Matz brought up, but this was 
more meant as a philosophical discussion (though I can see now that I 
was quite concrete.) It actually came in response to the whole 
"subclassing FalseClass and NilClass" discussion, where I believe the 
#to_b method would be more true to the idea of duck-typing.


Cheers,
Daniel