From: Dave Thomas <dave@...>
Date: 2008-03-18T23:42:31+09:00
Subject: Re: complex and rational


On Mar 18, 2008, at 8:41 AM, Paul Brannan wrote:

> Do you feel the same way about 'thread' and 'time'?

Actually, yes, but I can live more easily with than than with complex  
and rational.

If I say "require 'complex'" I expect it to add class complex to my  
runtime. Instead, we have a situation where I already have Complex  
there, and requiring something called 'complex' actually does  
something different--it actually hits just about every math class but  
never does _anything_ to class Complex.

So, I'd want to see one of two things: either Complex is initially  
nascent and then wakes up when you require 'complex', or have  
complex.rb renamed. Perhaps

    require 'math_traits'
    MathTraits::include :complex, :rational

or somesuch. (This would also give us the benefit of finer-grained  
control. For example, we could choose just to add support for Complex  
transcendentals).

Don't get me wrong--I like having them around. But sometimes when  
documenting things for the PickAxe, I find myself struggling to  
describe the rationale behind something. When that happens, I try to  
raise it as a potential issue in case the thing I'm describing could  
possibly be improved in the underlying language. It's the same thing  
as with Enumerable.member?. I don't see when 1..3 includes 2.5 but  
'a'..'b' does not include 'am'. I understand the underlying  
implementation perfectly--I struggle to explain the reason it is the  
way it is.


Dave