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Re: Interfaces
My half-baked proposal was a mutant hybrid of 'define module'
and 'define generic'. It was meant to subsume 'define generic',
and to group related generics into an interface within a module.
That is, it would have been as primary as 'define generic' is now.
P T Withington wrote in message ...
>Scott McKay swm@mediaone.net on 2000-07-03 23:15 wrote:
>
>>
>> Kim Barrett wrote in message <200007031924.PAA16768@life.ai.mit.edu>...
>>
>> [Quote from Moon]
>>
>>> Dylan does not require programmers to make a textual copy of portions
>>> of the definitions of items exported by a module, like a C header file
>>> or an Ada package declaration. In my opinion Dylan modules still have
>>> a well-defined interface; the difference is that we assume there will
>>> be the obvious development tools for printing out that interface,
>>> instead of requiring programmers to pretend to be tools and copy text
>>> from one file to another. (Except of course Dylan still requires
>>> programmers to copy the -names- of the exports from their definitions
>>> into the define module statement. We haven't thought of a good way to
>>> avoid that.)
>>
>>
>> If you want to declare an "interface" in Dylan right now, you copy the
>> names of functions into a module definition, and you copy the signature
>> from some set of methods into a 'define generic' form. So Dylan does,
>> in fact, require you to make "a textual copy of portions of the
definitions
>> of items exported by a module" if you want to collate this into an
>> "interface".
>> And you get to copy a little bit into one place, and another bigger bit
>> into another place. So I find Moon's argument less than persuasive...
>
>I would consider the generic's signature to be the original, not a copy.
>Then you implement the interface by writing methods that "subset" that
>signature. A default method might copy the signature of the generic, but
>any more specific methods must have a more constrained signature.
>
>> I have in the past proposed deprecating 'define generic' and augmenting
>> 'define module' to take its place. I haven't thought about this for a
year,
>> and I haven't written a real proposal, so don't bother to quiz me on it.
>
>I suppose if you could write the generic in your module declaration then
you
>wouldn't have to copy the name, as Moon complains. But you would still
need
>'define generic' for intra-module use, would you not?
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