What If..... Strong Types

[Don Garrett]

Huaiyu Zhu wrote:
> Don Garrett <garrett at bgb.cc> wrote:
> 
>>  I'm not suggesting any real changes to any, only proposing a thought 
>>experiment.
>>
>>  What if Python had been built from the start with strong types? And I mean 
>>strong types, not strong typing. The distinction I am trying to draw is that 
>>variables would not be typed, but that all types would have rigid interfaces.
>>
>>  Primarily, what if classes always had rigidly defined interfaces. I mean 
>>that public members had to be declared to exist, and that methods couldn't be 
>>modified on an instance. Private members could exist but would be really private.
>>
>>  All types would be classes (including ints and such). Amoung other things, 
>>I would add the concepts of Interfaces, instanceof operators.
>>
>>  Local variables would not require declaration, and would work just like 
>>today. Introspection would work, but be read-only.
>>
>>  My belief is that almost all the convenience of Python would be maintained, 
>>but that compilation, optimization, and automated code analysis would be simpler.
>>
>>  I'm just wondering if the change would be good or bad. Would it really 
>>break anything important in Python today? Would it prevent any common errors? 
>>Would it help with automated code analysis (compilation and optimization 
>>included) as much as I think it would?
> 

<Excellent discussion of seperation of interface and implementation snipped>

   Have you, by chance, ever used Sather? It was (I think development is 
stopped) an Eiffel inspired language that seperated interface and 
implementation inheritance (amoung several other cool ideas). Unfotunatly, I 
never got to use it for any large projects, so never felt that I learned it well.

   http://www.icsi.berkeley.edu/~sather/


-- 
Don Garrett                             http://www.bgb.cc/garrett/
BGB Consulting                                      garrett at bgb.cc