--- a/src/core_util.sml	Sat Aug 16 14:45:23 2008 -0400
+++ b/src/core_util.sml	Sat Aug 16 15:03:05 2008 -0400
@@ -54,6 +54,10 @@
       | (_, KRecord _) => GREATER
 
       | (KUnit, KUnit) => EQUAL
+      | (KUnit, _) => LESS
+      | (_, KUnit) => GREATER
+
+      | (KTuple ks1, KTuple ks2) => joinL compare (ks1, ks2)
 
 fun mapfold f =
     let
@@ -79,6 +83,11 @@
                            (KRecord k', loc))
 
               | KUnit => S.return2 kAll
+
+              | KTuple ks =>
+                S.map2 (ListUtil.mapfold mfk ks,
+                        fn ks' =>
+                           (KTuple ks', loc))
     in
         mfk
     end
@@ -170,6 +179,15 @@
       | (_, CFold _) => GREATER
 
       | (CUnit, CUnit) => EQUAL
+      | (CUnit, _) => LESS
+      | (_, CUnit) => GREATER
+
+      | (CTuple cs1, CTuple cs2) => joinL compare (cs1, cs2)
+      | (CTuple _, _) => LESS
+      | (_, CTuple _) => GREATER
+
+      | (CProj (c1, n1), CProj (c2, n2)) => join (Int.compare (n1, n2),
+                                                  fn () => compare (c1, c2))
 
 datatype binder =
          Rel of string * kind
@@ -245,6 +263,16 @@
                                        (CFold (k1', k2'), loc)))
 
               | CUnit => S.return2 cAll
+
+              | CTuple cs =>
+                S.map2 (ListUtil.mapfold (mfc ctx) cs,
+                        fn cs' =>
+                           (CTuple cs', loc))
+
+              | CProj (c, n) =>
+                S.map2 (mfc ctx c,
+                        fn c' =>
+                           (CProj (c', n), loc))
     in
         mfc
     end