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| Date: | -- (:) |
| From: | skaller <skaller@u...> |
| Subject: | Re: [Caml-list] type matching |
On Sat, 2004-09-18 at 00:53, Flávio Leonardo Cavalcanti de Moura wrote: > Hi there, > > I am trying to build a normalisation function for lambda terms which > This expression has type exlambda * int * 'a list * string > but is here used with type Setypes.exlambda * int * int list * string > > My dout is: shouldn't the type exlambda match with the type > Setypes.exlambda as well as 'a list with int list in the two last line > above? > > Why Ocaml differ between the types Setypes.exlambda and exlambda? module type X = sig type t end module Y = struct type t = int end --> module Y : sig type t = int end module Z : X = Y --> module Z : X let i : Y.t = 1 --> val x : Y.t = 1 let ni : Z.t = 1 --> This expression has type int but is here used with type Z.t Y.t is just an alias for 'int' However Z.t is an abstract type because X.t is. -- John Skaller, mailto:skaller@users.sf.net voice: 061-2-9660-0850, snail: PO BOX 401 Glebe NSW 2037 Australia Checkout the Felix programming language http://felix.sf.net ------------------- 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