Re: New copying license for classes/modules: CGPL

[rodemann@mathematik.uni-ulm.de (Joerg Rodemann)]

Bertrand Meyer (Bertrand.Meyer@eiffel.com) wrote:
  
> As far as I understand the discussion, the problem will not
> arise for Eiffel. The language is designed so that the code of
> generic classes need not be duplicated for different
> "generic derivations" of the same generic class
> (i.e. different types obtained by providing different generic
> parameters, as in LIST [BOAT] and LIST [PERSON]).  
> Our implementation, and I believe others too, indeed do not
> duplicate the code in such cases. Nor is there any need to
> "copy the code into your program".

Well, sorry to raise this topic again, we had a long discussion about that
shortly and it's still continuing, but this seems to point to some problems
we discussed in a concrete situation: how is the Eiffel system going to check
the usage of a class versus its specification (seems we agreed on the term
short-flat form as a similar concept to the Ada spec.) Is the Eiffel system
able to check against the compiled library or is it more likely to leave that
to the linker as in C++? (Sure, you can check against header files there, but
who tells you they are correct, until you link it into an executable?)

Is this a problem and a point for separated interface/implementation way?
Or is there a simple solution? If so how does it work? Certainly you would
not like to include the complete library source, would you?

> (Please note that this observation includes no criticism or even
> mention of Ada; its intention is simply, since Robert Dewar's
> message was cross-posted to comp.lang.eiffel, to address his
> point insofar as they apply to Eiffel.)

> More generally I think that the idea of  adapting the Gnu
> Public License to cover reusable O-O components is excellent.

Agreed: the time is ripe to think about reusing in a larger way. And I would
like to see a much better interoperability between OO-languages as well.

Regards

Joerg


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rodemann@mathematik.uni-ulm.de | Dipl.-Phys. Joerg S. Rodemann
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