simplified ProofContext.assume interface;

--- a/src/Pure/Isar/proof.ML	Wed Oct 24 17:38:29 2001 +0200
+++ b/src/Pure/Isar/proof.ML	Wed Oct 24 19:18:10 2001 +0200
@@ -515,9 +515,7 @@
   state
   |> assert_forward
   |> map_context_result (f exp args)
-  |> (fn (st, (factss, prems)) =>
-    these_factss (st, factss)
-    |> put_thms ("prems", prems));
+  |> these_factss;
 
 val assm = gen_assume ProofContext.assume;
 val assm_i = gen_assume ProofContext.assume_i;