Python from Wise Guy's Viewpoint

[Andreas Rossberg]

Raffael Cavallaro wrote:
> Matthias Blume <find at my.address.elsewhere> wrote in message news:<m11xsx2aiu.fsf at tti5.uchicago.edu>...
> 
>>[This whole discussion is entirely due to a mismatch of our notions of
>>what constitutes expressive power.]
> 
> No, it is due to your desire to be type constrained inappropriately
> early in the development process.

Oh my. How is this related?

I think Matthias' is absolutely right. The mismatch here is that some 
fail to understand that - obviously, one should hope - the ability to 
express restrictions is an ability to express something, i.e. expressive 
power. Otherwise assertions, pre/post conditions, probably exceptions 
and similar stuff wouldn't carry any expressive power either. Which of 
course is nonsense.

> Lispers know that early on, you
> don't care about type constraints because you haven't settled on your
> final data representations yet.

Another repeated misunderstanding. When I use types in early coding 
phases in ML for example, these types are mostly abstract. They don't 
say anything about representations. All checking takes place against 
abstract types, whose representation is fully exchangable.

> With lisp, you only add as much type checking as you need, *when* you
> need it.

Yes, and you also loose most of the benefits of typing...

-- 
Andreas Rossberg, rossberg at ps.uni-sb.de

"Computer games don't affect kids; I mean if Pac Man affected us
  as kids, we would all be running around in darkened rooms, munching
  magic pills, and listening to repetitive electronic music."
  - Kristian Wilson, Nintendo Inc.