dynamic classes and duck typing

[Michal Minich]

Hello retard,

> Tue, 01 Dec 2009 14:24:01 -0800, Walter Bright wrote:
> 
>> dsimcha wrote:
>> 
>>> My biggest gripe about static verification is that it can't help you
>>> at all with high-level logic/algorithmic errors, only lower level
>>> coding errors.  Good unit tests (and good asserts), on the other
>>> hand, are invaluable for finding and debugging high-level logic and
>>> algorithmic errors.
>>> 
>> Unit tests have their limitations as well. Unit tests cannot prove a
>> function is pure, for example.
>> 
> Sure, unit tests can't prove that.
> 
>> Both unit tests and static verification are needed.
>> 
> But it doesn't lead to this conclusion. Static verification is
> sometimes very expensive and real world business applications don't
> need those guarantees that often. It's ok if a web site or game
> crashes every now and then. If I need serious static verification, I
> would use tools like Coq, not D..
> 

Static verification in Coq is very expensive, but who really does that for 
real world programs. I think we are talking about automatic static verification 
with none or minimal programmer assistance - it will get you assurances for 
larger project with multiple programmers - that various parts plug in correctly 
(typecheck) and that they do not affect other parts of program in unexpected 
ways (const/pure/safe) - then you are at good ground to verify yours program 
logic by yourself (debugging/pre(post)conditions/unittests/asserts/invariants).