On Sat, 19 May 2007, Martin Rubey wrote: | Dear Gaby & Waldek, | | as you may know, there is a problem fixing bug #354, Complex R is not | necessarily a field when R is a field. | | It would be quite straightforward to fix it, if we could conditionally export | Field, depending on a Boolean valued function, like | | if R has Field and R has Finite and size()$R rem 4 = 1 then Field | | Currently, spad seems to accept statements of the form | | D has C | | and | | D1 is d2 | | only. (Please check this, I'm not entirely sure.) Do you think it would be | difficult to fix this? I do not see a workaround, unfortunately.
Martin -- I believe you raise a fundamental problem, which is that Spad should allow combination of predicate through usual logical operators. For a given specific case, one might look for a workaround that simulates type checking at runtime. However, I don't believe that is a good way forward: (1) that usually leads to unnatual, unmaintainable code in the long run; (2) we fail to express directly what our ideas; (3) it is not clear we have a coherent systematic approach. Therefore, I believe this is an issue that should be given thought. -- Gaby _______________________________________________ Axiom-developer mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/axiom-developer
