]> Thanks for your help. On Wed, 23 Jul 2003, Jacques Garrigue wrote: > This precise type is not admissible in the ocaml type system. > In ocaml recursive types must be regular: only 'a foo may occur in the > expansion of 'a foo. Ah. Any hope of getting this fixed? > > This problem is discussed in an answer to PR#1730 in the caml bug > database. Unfortunately, I don't speak french. > This can be solved by introducing an explicit wrapper. This is one possibility. > If you think (as I do) that all these examples are just too > complicated in practice, there is a simpler way to go: > only define a fold method in your class, and define map itself out of > the class. Maybe I'm asking the wrong question. I need/want map to behave differently when called on different subtypes of foo. In a pseudo java/ocaml mix, I want to do: let map f x = if x instanceof 'a foo_map then let e = ('a foo_map) in (* various code dealing with an already mapped foo *) else (* various code dealing with an arbitrary unmapped foo *) The obvious way to do this to me is to make map a member function. But this wouldn't be the first time I was missing something obvious. Brian ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners