Next step after pychecker

[huy]

Paul Rubin wrote:
> Philippe Fremy <phil at freehackers.org> writes:
> 
>>I would like to develop a tool that goes one step further than
>>pychecker to ensure python program validity. The idea would be to get
>>close to what people get on ocaml: a static verification of all types
>>of the program, without any kind of variable declaration. This would
>>definitely brings a lot of power to python.
> 
> 
> You know, I've always thought that ML-style type inference is an
> impressive technical feat, but why is it so important to not use
> declarations?  This is an aspect I've never really understood.

You know, I think I agree ;-). Just because you don't declare the types, 
doesn't mean you can change the implicit type willy nilly anyway; at 
least for more complex programs anyway. In fact, it would be safer to 
have type checking when you want to do something like this. I currently 
needed to change a number parameter to a string parameter (found out 
order_no wasn't just numbers as specs had specified). Of course this 
parameter was being used in a great many places. Changing it was a bit 
scary because we had to make sure it wasn't being treated as a number 
anywhere throughout the code. Yes good coverage with unit tests would 
have helped but unfortunately we do not yet have good coverage. TDD is a 
quite hard to practice as a beginner.

Cheers,

Huy