setup for dynamic "prems" (legacy);

--- a/src/Pure/assumption.ML	Tue Mar 25 19:39:57 2008 +0100
+++ b/src/Pure/assumption.ML	Tue Mar 25 19:39:58 2008 +0100
@@ -76,6 +76,13 @@
 fun extra_hyps ctxt th = subtract (op aconv) (map Thm.term_of (assms_of ctxt)) (Thm.hyps_of th);
 
 
+(* named prems -- legacy feature *)
+
+val _ = Context.add_setup
+  (PureThy.add_thms_dynamic ("prems",
+    fn Context.Theory _ => [] | Context.Proof ctxt => prems_of ctxt));
+
+
 (* add assumptions *)
 
 fun add_assms export new_asms =