Re: [Axiom-developer] Re: SPAD and Aldor again

[C Y]

Waldek Hebisch wrote:
> Martin Rubey wrote:
>> C Y <address@hidden> writes:
>>
>>> I think we should make the decision as a project not to wait any longer for
>>> Aldor, and commit to improving SPAD - up until now I think there has been
>>> hesitation to commit serious effort to SPAD due to the possibility of Aldor
>>> becoming available and making such work unnecessary.  To my mind the first
>>> step to improving SPAD is to decide what SPAD should be, since right now it
>>> doesn't have a formal language definition.
>> For me this is totally clear: SPAD should become a free implementation of the
>> Aldor language. It would not make sense to have to different languages 
>> around.
>>
> 
> I am affraid we will have two different languages: there are legal reasons

Indeed.  The Aldor documentation is not free at all, and any attempt to
define Aldor in a literate style would have to duplicate Aldor without
duplicating too closely its documentation - that's a real problem.

> and technical ones: I do not see why we should limit ourselfs to capabilites
> present in Aldor and (assuming that we want this) implementing _all_
> capabilities of Aldor is likely to take long time.  I do not want to
> underestimate big things (dependent types) but getting little details
> 100% compatible would probably take more time.

I don't know the full history of Aldor, but my impression is that it
grew beyond just being "the language used to implement mathematics in
Axiom" into a more general purpose language.  We need a language to
implement mathematics in Axiom, so hopefully retaining that focus will
make the task somewhat simpler.

> I do not want to diverge just for beeing different, but agreeing that
> we just one _some_ Aldor features in Axiom language is IMHO a better
> way: we will not waste time trying to be 100% compatible.

Agreed.  One thought - it looks like libaldor and Algebra were Manuel
Bronstein's projects - did he assign copyright to Aldor.org or was it
still his projects and just being distributed with Aldor.org's offering?
 If so perhaps that could make use of those libraries (if they become
available) and target SPAD to support them, perhaps tweaking both as needed.

I know that situation is moving slowly as well (quite understandable) so
perhaps a logical direction to take is look at what features are used in
libaldor, Algebra, SumIT etc. and see what would be required to support
those libraries directly that SPAD doesn't supply.

>> And, as you know, in my opinion the first step in making this happen is to 
>> make
>> the Axiom interpreter (!) understand Aldor generated code, i.e., dependent
>> types.
>>
> 
> I tend to think that adding dependent types to compiler is easier: compiler
> has to do typechecking and probably some runtime support (the rest should
> work the same).  Interpreter needs more runtime support and type 
> inferencing.  Inferencing is harder. And of course there is added burden
> of keeping thing Aldor compatible.

I think that will be an important discussion to be had as a project -
just how compatible with Aldor we want to stay.

Cheers,
CY