diff tests/foldm.lac @ 75:88ffb3d61817

Folding through a functor
author Adam Chlipala <adamc@hcoop.net>
date Thu, 26 Jun 2008 12:35:26 -0400
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/foldm.lac	Thu Jun 26 12:35:26 2008 -0400
@@ -0,0 +1,26 @@
+con currier = fold (fn nm => fn t => fn acc => t -> acc) {}
+
+signature S = sig
+        type t
+        val x : t
+
+        con rs :: {Type}
+        val create : currier rs -> t
+end
+
+functor Currier (M : sig con rs :: {Type} end) : S where con rs = M.rs = struct
+        val currier : rs :: {Type} -> currier rs =
+                fold [currier] (fn nm :: Name => fn t :: Type => fn rest :: {Type} => fn acc => fn x : t => acc) {}
+
+        type t = currier M.rs
+        val x = currier [M.rs]
+
+        con rs = M.rs
+        val create : t -> t = fn x => x
+end
+
+structure ChefsSpecial = Currier(struct
+        con rs = [A = int, B = float]
+end)
+
+val main = ChefsSpecial.x