Gabriel Dos Reis <[EMAIL PROTECTED]> writes: > I believe you raise a fundamental problem, which is that Spad > should allow combination of predicate through usual logical operators.
"combinations of predicates through usual logical operators." *are* allowed. Only, in the context of conditional exports, predicates are limited to "is" and "has". Aldor, in contrast, makes no (or maybe, not much) difference to other parts of the code here. Thus, my question is, would it be easy, or at least, doable for you, to make SPAD behave like Aldor here, i.e. drop the restriction on the predicates allowed? > For a given specific case, one might look for a workaround that simulates > type checking at runtime. I doubt this. Of course, using Waldek's idea we could say that 'Complex F' is only allowed if either F is not a field or x^2+1 is irreducible in F. But I'm not sure if that's what we want. And I doubt that you can achieve what I first proposed in current SPAD, namely, make 'Complex F' export 'Field' only if x^2+1 is irreducible in F. I guess, your answer (whether it would be "easy"), is "no"... Martin _______________________________________________ Axiom-developer mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/axiom-developer
