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diff lib/ur/basis.urs @ 1293:acabf3935060

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tryDml
author Adam Chlipala <adam@chlipala.net>
date Sun, 05 Sep 2010 14:00:57 -0400
parents a671c986f517
children b106ca8200b1
line wrap: on
line diff
--- a/lib/ur/basis.urs	Sun Sep 05 12:50:06 2010 -0400
+++ b/lib/ur/basis.urs	Sun Sep 05 14:00:57 2010 -0400
@@ -535,6 +535,8 @@
 
 type dml
 val dml : dml -> transaction unit
+val tryDml : dml -> transaction (option string)
+(* Returns an error message on failure. *)
 
 val insert : fields ::: {Type} -> uniques ::: {{Unit}}
              -> sql_table fields uniques