Re: class contract proposal finished

Paul Prescod wrote:
> Mark Hahn wrote:
>
>> http://prothon.org/wiki?pagename=DesignByContractClass
>>
>> This works pretty much the same way as the properties proposal.  It
>> lets the interpreter do all the work.
>
> Fundamentally I've never understood the problem you are trying to
> solve here. I've heard of Design By Contract but I don't understand
> what your proposal has to do with it. I've always thought of Design
> By Contract as being about Eiffel-style preconditions and
> postconditions.
>
>
http://www.google.com/search?hl=en&lr=&ie=UTF-8&safe=off&q=design+by+contract+python&btnG=Search
>
> It has pretty little to do with a bunch of static-style rules on
> assigning to properties of objects etc.
>
> Designing features to allow large-scale software engineering is
> difficult and I don't think it is something you do off the top of your
> head. You need an articulated theory about how large-scale engineering
> works and why traditional languages fall short. Then you design the
> features to fix the problems. But your DBC has no rationale about why
> specific restrictions would realistically make it easier to build
> large programs.
>
> If you go back to Eiffel, you'll see that in their minds it is
> basically about a) runtime testing and b) static declarations. Unit
> testing is also promoted by modern "agile programming" methodologies.
> They are probably complimentary mechanisms and could work together. A
> language could add explicit support for both to make it easier.

So you feel the DBC type/interfaces proposal is also hopeless?

Yes, DBC is a formidable challenge. I felt the same way about unicode but
I've got it in the language now.  Not understanding something has never
stopped me before.  Why should I let it now?   :-)

I will study up on it more.  All I know is that I have seen many people come
to c.l.p. and say they couldn't use Python because of lack of DBC, type
enforcement, etc.  I now predict a new one with Prothon, and that is "lack
of classes".  I want to have an answer for them to give to their
pointy-haired bosses.