RE: [Axiom-developer] RE: Types as values, and Re: Static versusDynamicallytyped(was:Philosophy... )

[Vanuxem Gregory]

Hi,

> -----Message d'origine-----
> De : address@hidden
> [mailto:address@hidden la
> part de Martin Rubey
> Envoye : mardi 27 septembre 2005 14:03
> A : Ralf Hemmecke
> Cc : axiom-dev
> Objet : Re: [Axiom-developer] RE: Types as values,and Re: Static
> versusDynamicallytyped(was:Philosophy... )
>
>
> Ralf Hemmecke writes:
>  > William Sit wrote:
>  >
>  > > For example, if I have a constructor that requires an
> integral domain R as
>  > > a parameter, and I constructed in the package the quotient
> field of R, as
>  > > you may suggest as an explicit way to achieve efficiency,
> then the package
>  > > will FAIL if R is actually a field (you can consider this as
> a bug if you
>  > > like), even though a field IS an integral domain, mathematically.
>
> Why would it fail? I don't think it does, in fact. However, if
> you are going to
> apply FRAC you can simply ask whether the domain is a Field.
>
> On the other hand, given a Field to ask whether it is a QuotientField is a
> question that I consider quite important.
>
> However, the desirable query
>
>   if R has QuotientField S
>
> thus defining S is, I think, quite difficult to implement
> sensibly. Throughout
> Axiom, this effect is obtained by adding another parameter to the
> Package/Domain signature like:
>
> MyPackage(F: Field, S: IntegralDomain): ...
>
>   if F is Fraction S then

I think that works only in function definition but not in function
decalaration.


Cheers,

Greg

> Martin
>
>
>
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