[Axiom-mail] Re: [Axiom-developer] NNI to SingleInteger

[Martin Rubey]

Ralf <address@hidden> writes:

> Hello,
> 
> does somebody know the proper method/function to convert between
> 
> NNI, PI, SingleInteger, Integer

I guss to go from x: NNI to SingleInteger you have to say

retract(x::INT)@SingleInteger

Usually, in axiom, if a "coercion" (in the general, not Axiom sense of the
word) cannot always been done, as for example from INT to NNI or from INT to
SINT, you have to use "retract".

There are two very nice categories, namely KOERCE and RETRACT. Unfortunately,
not all domains have these categories, although they should. The reason is,
that SPADdoesn't know extend.

As soon as extend is available, this must be changed, since it makes
"categorial" programming possible.

I guess there is no "retract" in libaldor?

Martin