--- a/lib/top.urs	Sun Sep 14 11:02:18 2008 -0400
+++ b/lib/top.urs	Sun Sep 14 15:10:04 2008 -0400
@@ -1,9 +1,19 @@
 con idT = fn t :: Type => t
 con record = fn t :: {Type} => $t
+con fstTT = fn t :: (Type * Type) => t.1
+con sndTT = fn t :: (Type * Type) => t.2
 
 con mapTT = fn f :: Type -> Type => fold (fn nm t acc => [nm] ~ acc =>
         [nm = f t] ++ acc) []
 
+con mapT2T = fn f :: (Type * Type) -> Type => fold (fn nm t acc => [nm] ~ acc =>
+        [nm = f t] ++ acc) []
+
+con ex = fn tf :: (Type -> Type) =>
+        res ::: Type -> (choice :: Type -> tf choice -> res) -> res
+
+val ex : tf :: (Type -> Type) -> choice :: Type -> tf choice -> ex tf
+
 val compose : t1 ::: Type -> t2 ::: Type -> t3 ::: Type
         -> (t2 -> t3) -> (t1 -> t2) -> (t1 -> t3)
 
@@ -15,21 +25,42 @@
                 -> tf t -> tr rest -> tr ([nm = t] ++ rest))
         -> tr [] -> r :: {Type} -> $(mapTT tf r) -> tr r
 
+val foldT2R : tf :: ((Type * Type) -> Type) -> tr :: ({(Type * Type)} -> Type)
+        -> (nm :: Name -> t :: (Type * Type) -> rest :: {(Type * Type)} -> [nm] ~ rest
+                -> tf t -> tr rest -> tr ([nm = t] ++ rest))
+        -> tr [] -> r :: {(Type * Type)} -> $(mapT2T tf r) -> tr r
+
 val foldTR2 : tf1 :: (Type -> Type) -> tf2 :: (Type -> Type) -> tr :: ({Type} -> Type)
         -> (nm :: Name -> t :: Type -> rest :: {Type} -> [nm] ~ rest
                 -> tf1 t -> tf2 t -> tr rest -> tr ([nm = t] ++ rest))
         -> tr [] -> r :: {Type} -> $(mapTT tf1 r) -> $(mapTT tf2 r) -> tr r
 
+val foldT2R2 : tf1 :: ((Type * Type) -> Type) -> tf2 :: ((Type * Type) -> Type)
+        -> tr :: ({(Type * Type)} -> Type)
+        -> (nm :: Name -> t :: (Type * Type) -> rest :: {(Type * Type)} -> [nm] ~ rest
+                -> tf1 t -> tf2 t -> tr rest -> tr ([nm = t] ++ rest))
+        -> tr [] -> r :: {(Type * Type)} -> $(mapT2T tf1 r) -> $(mapT2T tf2 r) -> tr r
+
 val foldTRX : tf :: (Type -> Type) -> ctx :: {Unit}
         -> (nm :: Name -> t :: Type -> rest :: {Type} -> [nm] ~ rest
                 -> tf t -> xml ctx [] [])
         -> r :: {Type} -> $(mapTT tf r) -> xml ctx [] []
 
+val foldT2RX : tf :: ((Type * Type) -> Type) -> ctx :: {Unit}
+        -> (nm :: Name -> t :: (Type * Type) -> rest :: {(Type * Type)} -> [nm] ~ rest
+                -> tf t -> xml ctx [] [])
+        -> r :: {(Type * Type)} -> $(mapT2T tf r) -> xml ctx [] []
+
 val foldTRX2 : tf1 :: (Type -> Type) -> tf2 :: (Type -> Type) -> ctx :: {Unit}
         -> (nm :: Name -> t :: Type -> rest :: {Type} -> [nm] ~ rest
                 -> tf1 t -> tf2 t -> xml ctx [] [])
         -> r :: {Type} -> $(mapTT tf1 r) -> $(mapTT tf2 r) -> xml ctx [] []
 
+val foldT2RX2 : tf1 :: ((Type * Type) -> Type) -> tf2 :: ((Type * Type) -> Type) -> ctx :: {Unit}
+        -> (nm :: Name -> t :: (Type * Type) -> rest :: {(Type * Type)} -> [nm] ~ rest
+                -> tf1 t -> tf2 t -> xml ctx [] [])
+        -> r :: {(Type * Type)} -> $(mapT2T tf1 r) -> $(mapT2T tf2 r) -> xml ctx [] []
+
 val queryX : tables ::: {{Type}} -> exps ::: {Type} -> ctx ::: {Unit}
         -> sql_query tables exps -> tables ~ exps
         -> ($(exps ++ fold (fn nm (fields :: {Type}) acc => [nm] ~ acc => [nm = $fields] ++ acc) [] tables)