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annotate tests/functor.lac @ 43:d94c484337d0

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Subtyping for functor signatures
author Adam Chlipala <adamc@hcoop.net>
date Thu, 19 Jun 2008 16:43:24 -0400
parents b3fbbc6cb1e5
children a9f3ce2d1b9b
rev   line source
adamc@40 1 signature S = sig
adamc@40 2 type t
adamc@40 3 val z : t
adamc@40 4 val s : t -> t
adamc@40 5 end
adamc@40 6
adamc@40 7 signature T = sig
adamc@40 8 type t
adamc@40 9 val three : t
adamc@40 10 end
adamc@40 11
adamc@42 12 functor F (M : S) : T where type t = M.t = struct
adamc@41 13 type t = M.t
adamc@40 14 val three = M.s (M.s (M.s M.z))
adamc@40 15 end
adamc@43 16
adamc@43 17 structure F2 : functor (M : S) : T where type t = M.t = F
adamc@43 18 structure F3 : functor (M : S) : T = F
adamc@43 19 (*structure F4 : functor (M : S) : sig type q end = F*)
adamc@43 20 (*structure F5 : functor (M : S) : T where type t = int = F*)