src/Pure/General/table.ML

 
 end;
 
 structure Inttab = TableFun(type key = int val ord = int_ord);
 structure Symtab = TableFun(type key = string val ord = fast_string_ord);
+structure PStrStrTab = TableFun(
+  type key = string * string
+  val ord = prod_ord fast_string_ord fast_string_ord
+);