>> Functor is quite loaded name and may lead to confusion. > > Yes, the name is a problem. OpenAxiom uses "Functorial". > But I think Functor is fine, given the context that Haskell is > using this name.

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BTW, in Aldor the "Maybe" domain is called "Partial". https://github.com/pippijn/aldor/blob/master/aldor/lib/aldor/src/base/sal_partial.as Traditionally, my usage of the term "functor" in the context of AXIOM/FriCAS would be that it is any parametrized domain. If a (domain)constructor with name Functor is introduced, that would confuse me a bit, if that thing is restricted to just export map: (S -> S, %) -> % Additionally, if the definition is Functor(S : Type) : Category == Type with map: (S -> S, %) -> % then this "Functor" is of type "Category" and this I find rather strange. If one defines "Foo(X: Category): Category == ..." then I would be tempted to call Foo (which can be seen as a "function" with type Category->Category) as a Functor, but you want "Functor" instead of "Foo" and that does not fit with category theory in my understanding. Like Waldek, I also think that MapCategory2 would fit better into FriCAS. I am not so much in favour of copying the terminology of Haskell. In particular, if FriCAS is going to implement > Monad(S : Type) : Category == Type with > _>_> : (%, S -> %) -> % that would confuse me quite a bit. Naming of functions and domains aside, I find this implementation somewhat hacky, in particular the line starting with "if FA is Maybe A". > )abbrev package FUNCTOR2 FunctorPackage > FunctorPackage(A : Type, B : Type, FA : Functor A, FB : Functor B) : > Exports == Implementation where > Exports == with > map : (A -> B, FA) -> FB > Implementation == add > if FA is Maybe A and FB is Maybe B then > map(f, fa) == > if nothing?(fa)$Maybe(A) then nothing()$Maybe(B) > just f fromJust fa If FA and FB are restricted to just one domain, then why would one want to put them as parameters? FunctorPackage(A : Type, B : Type) : Exports == Implementation where FA ==> Maybe A FB ==> Maybe B Exports == with map : (A -> B, FA) -> FB Implementation == add map(f, fa) == if nothing?(fa)$FA then nothing()$FB just f fromJust fa You probably suggested that, because the "if" line shouldn't be there and you actually wanted something that applies to all pairs of monads. But your FunctorPackage just does the lifting of map for only one particular monad (namely Maybe). I'm still of the opinion that the concept of monads cannot be nicely defined in SPAD. https://groups.google.com/d/msg/fricas-devel/UCFkQGgOOf0/RzbEtrbYIHUJ Note that in https://wiki.haskell.org/Monad class Monad m where (>>=) :: m a -> (a -> m b) -> m b (>>) :: m a -> m b -> m b return :: a -> m a fail :: String -> m a the "m" appears in front of a and in front of b. I'm not aware of a SPAD/Aldor syntax that can describe this situation. Ralf -- 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 fricas-devel+unsubscr...@googlegroups.com. To post to this group, send email to fricas-devel@googlegroups.com. Visit this group at https://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.