# HG changeset patch
# User Adam Chlipala <adamc@hcoop.net>
# Date 1223164619 14400
# Node ID b88f4297167f85e07a241bfc5ceee997886b5fe7
# Parent  58eeeb3cbf40d8e2a1184ada6f4009bd641cbe04
Improved inference of records of tuples

diff -r 58eeeb3cbf40 -r b88f4297167f src/elaborate.sml
--- a/src/elaborate.sml	Sat Oct 04 16:15:13 2008 -0400
+++ b/src/elaborate.sml	Sat Oct 04 19:56:59 2008 -0400
@@ -689,10 +689,15 @@
                     ([], [], [], [])
                 else
                     (fs1, fs2, others1, others2)
+              | (_, [], [], [other2]) =>
+                if isGuessable (other2, fs1) then
+                    ([], [], [], [])
+                else
+                    (fs1, fs2, others1, others2)
               | _ => (fs1, fs2, others1, others2)
 
         (*val () = eprefaces "Summaries5" [("#1", p_summary env {fields = fs1, unifs = unifs1, others = others1}),
-                                         ("#2", p_summary env {fields = fs2, unifs = unifs2, others = others2})]*)
+                                           ("#2", p_summary env {fields = fs2, unifs = unifs2, others = others2})]*)
 
         val clear = case (fs1, others1, fs2, others2) of
                          ([], [], [], []) => true
@@ -889,6 +894,25 @@
                                        gs' @ gs
                                    end) [] (cs1, cs2))
              handle ListPair.UnequalLengths => err CIncompatible)
+
+          | (L'.CProj ((L'.CUnif (_, _, _, ref (SOME c1)), loc), n1), _) =>
+            unifyCons' (env, denv) (L'.CProj (c1, n1), loc) c2All
+          | (_, L'.CProj ((L'.CUnif (_, _, _, ref (SOME c2)), loc), n2)) =>
+            unifyCons' (env, denv) c1All (L'.CProj (c2, n2), loc)
+          | (L'.CProj ((L'.CUnif (_, (L'.KTuple ks, _), _, r), loc), n), _) =>
+            let
+                val us = map (fn k => cunif (loc, k)) ks
+            in
+                r := SOME (L'.CTuple us, loc);
+                unifyCons' (env, denv) (List.nth (us, n - 1)) c2All
+            end
+          | (_, L'.CProj ((L'.CUnif (_, (L'.KTuple ks, _), _, r), loc), n)) =>
+            let
+                val us = map (fn k => cunif (loc, k)) ks
+            in
+                r := SOME (L'.CTuple us, loc);
+                unifyCons' (env, denv) c1All (List.nth (us, n - 1))
+            end
           | (L'.CProj (c1, n1), L'.CProj (c2, n2)) =>
             if n1 = n2 then
                 unifyCons' (env, denv) c1 c2
diff -r 58eeeb3cbf40 -r b88f4297167f tests/crud1.ur
--- a/tests/crud1.ur	Sat Oct 04 16:15:13 2008 -0400
+++ b/tests/crud1.ur	Sat Oct 04 19:56:59 2008 -0400
@@ -1,13 +1,6 @@
 table t1 : {Id : int, A : int, B : string, C : float, D : bool}
 
 open Crud.Make(struct
-        con cols :: {(Type * Type)} = [
-                A = (int, string),
-                B = (string, string),
-                C = (float, string),
-                D = (bool, bool)
-        ]
-
         val tab = t1
 
         val title = "Crud1"