Re: [Axiom-developer] Problem with defining Zero

[Ralf Hemmecke]

Hello Antoine.


First, in Aldor it is suggested to write
  Rep == LPF;
instead of your
  Rep ==> LPF;

Second, there is some magic going on here that I cannot explain.

http://wiki.axiom-developer.org/SandBoxZero

Clearly, you specify:

   Zero:() -> % ;

in the exports, but nowhere you say something like

  0: %

So it should be clear that there is no 0$NTBA.
HOWEVER, why does Axiom )show the signature

  0: () -> %

Can somebody explain why Zero and 0 should be the same? I am almost 100% 
sure that there is not such syntactic sugar in the Aldor compiler, so I 
guess Axiom is treating Zero and 0 identically, **but** not in finding 
the implementation. Is that behaviour documented somewhere in Axiom?

How to do it right?

Replace
   Zero:() -> % ;
by
  0: %;
and
  Zero():% == { per [0$FP] }
by
   0 :% == { per [0$FP] }

And say

   dummy (f:%):% == 0;

The )show will be identical. STRANGE!!! It should show
  0: %
instead of
  0: () -> %

But

(3) -> 0$NTBA(x,FRAC INT)

   (3)  D [0]

works.

Ralf