[Axiom-developer] Re: [Aldor-l] exports and constants

[Christian Aistleitner]

Hello


> stdout << ( A      has CatA) << newline;
> stdout << ((A add) has CatA) << newline;
>
> It still does not compile. But it should. Both A and "A add" are domains
> of type CatA.

Why should (A add) be of static type CatA? (I assume you meant static type  
although has checks the dynamic type, which of course is something  
different. The Aldor compiler complains about the static type of "A add".)

If (A add) had static type with {} in this context, it would be perfectly  
fine for me. Nevertheless, it is a bug. Once a again a bug, where the add  
statement cannot determine which static type it has to satisfy. If you  
hint the compiler, it should work.

> What I wanted to demonstrate is that "A add {...}" has a type and is a
> value of its own.
>
> But if used in a context like "X: CatX == ... " it does matter whether
> there is an "add" *explicitly* appearing on the right hand side. That is
> not just an ordinary assignment of constants, i.e.
>
> constName: SomeType == somevalue;

Why not? It's just a different "somevalue".
I have not seen any code that cannot be explained by the "add is allowed  
to cut off fields" principle or the "add cannot determine the type it has  
to fulfill" bug.

--
Kind regards,
Christian