src/Pure/Syntax/parser.ML

--- a/src/Pure/Syntax/parser.ML	Sun Dec 28 14:56:09 1997 +0100
+++ b/src/Pure/Syntax/parser.ML	Sun Dec 28 14:56:44 1997 +0100
@@ -427,7 +427,7 @@
 
 (*The mother of all grammars*)
 val empty_gram = Gram {nt_count = 0, prod_count = 0,
-                       tags = Symtab.null, chains = [], lambdas = [],
+                       tags = Symtab.empty, chains = [], lambdas = [],
                        prods = Array.array (0, (([], []), []))};