To Ralf: yes, the failed()$Maybe is like NULL from C,
a unique global special value to indicate failure.
We make that clear in documentation, then there's no
problem. After all, there's currently no usage of
Union("failed", Union("failed", X)) in the code, and
there's only one Rep use Union("failed", X), PatternMatchResult.
> BTW, if X1 := Union(X,"failed") and X2 := Union(X1,"failed"), where in
> current FriCAS is it specified that failed$X1 is different from failed$X2?
Well, currently there's no '=' for Union, and you can't compare
different types. And if you cast failed$X1 into X2, it's same as
failed$X2, just like the current Maybe.
--
You received this message because you are subscribed to the Google Groups
"FriCAS - computer algebra system" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/fricas-devel.
For more options, visit https://groups.google.com/d/optout.
