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diff src/disjoint.sml @ 709:0406e9cccb72

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FOREIGN KEY, without ability to link NULL to NOT NULL (and with some lingering problems in row inference)
author Adam Chlipala <adamc@hcoop.net>
date Tue, 07 Apr 2009 18:47:47 -0400
parents 12b73f3c108e
children a779402841f6
line wrap: on
line diff
--- a/src/disjoint.sml	Tue Apr 07 16:22:11 2009 -0400
+++ b/src/disjoint.sml	Tue Apr 07 18:47:47 2009 -0400
@@ -254,7 +254,8 @@
         val hasUnknown = List.exists (fn Unknown _ => true | _ => false)
         val unUnknown = List.mapPartial (fn Unknown _ => NONE | Piece p => SOME p)
     in
-        if hasUnknown ps1 orelse hasUnknown ps2 then
+        if (hasUnknown ps1 andalso not (List.null ps2))
+           orelse (hasUnknown ps2 andalso not (List.null ps1)) then
             [(loc, env, denv, c1, c2)]
         else
             let