thms_containing: allow "_" in specification;

--- a/doc-src/IsarRef/pure.tex	Tue Aug 27 17:24:41 2002 +0200
+++ b/doc-src/IsarRef/pure.tex	Tue Aug 27 17:25:44 2002 +0200
@@ -1390,9 +1390,9 @@
   
 \item [$\isarkeyword{thms_containing}~\vec t$] retrieves facts from the theory
   or proof context containing all of the constants or variables occurring in
-  terms $\vec t$.  Note that giving the empty list yields \emph{all} currently
-  known facts.  An optional limit for the number printed facts may be given;
-  the default is 40.
+  terms $\vec t$ (which may contain occurrences of ``$\_$'').  Note that
+  giving the empty list yields \emph{all} currently known facts.  An optional
+  limit for the number printed facts may be given; the default is 40.
   
 \item [$\isarkeyword{thm_deps}~\vec a$] visualizes dependencies of facts,
   using Isabelle's graph browser tool (see also \cite{isabelle-sys}).

--- a/src/Pure/Isar/proof_context.ML	Tue Aug 27 17:24:41 2002 +0200
+++ b/src/Pure/Isar/proof_context.ML	Tue Aug 27 17:25:44 2002 +0200
@@ -552,28 +552,29 @@
 
 local
 
-fun gen_read read app is_pat schematic (ctxt as Context {defs = (_, _, used, _), ...}) s =
+fun gen_read read app is_pat dummies schematic (ctxt as Context {defs = (_, _, used, _), ...}) s =
   (transform_error (read (syn_of ctxt)
       (sign_of ctxt) (def_type ctxt is_pat, def_sort ctxt, used)) s
     handle TERM (msg, _) => raise CONTEXT (msg, ctxt)
     | ERROR_MESSAGE msg => raise CONTEXT (msg, ctxt))
   |> app (intern_skolem ctxt)
   |> app (if is_pat then I else norm_term ctxt schematic)
-  |> app (if is_pat then prepare_dummies else (reject_dummies ctxt));
+  |> app (if is_pat then prepare_dummies else if dummies then I else reject_dummies ctxt);
 
 in
 
-val read_termTs = gen_read (read_def_termTs false) (apfst o map) false false;
-val read_termT_pats = #1 oo gen_read (read_def_termTs false) (apfst o map) true false;
+val read_termTs = gen_read (read_def_termTs false) (apfst o map) false false false;
+val read_termT_pats = #1 oo gen_read (read_def_termTs false) (apfst o map) true false false;
 
 fun read_term_pats T ctxt pats = read_termT_pats ctxt (map (rpair T) pats);
 val read_prop_pats = read_term_pats propT;
 
-val read_term = gen_read (read_term_sg true) I false false;
-val read_prop = gen_read (read_prop_sg true) I false false;
-val read_prop_schematic = gen_read (read_prop_sg true) I false true;
-val read_terms = gen_read (read_terms_sg true) map false false;
-val read_props = gen_read (read_props_sg true) map false;
+val read_term = gen_read (read_term_sg true) I false false false;
+val read_term_dummies = gen_read (read_term_sg true) I false true false;
+val read_prop = gen_read (read_prop_sg true) I false false false;
+val read_prop_schematic = gen_read (read_prop_sg true) I false false true;
+val read_terms = gen_read (read_terms_sg true) map false false false;
+val read_props = gen_read (read_props_sg true) map false false;
 
 end;
 
@@ -1409,7 +1410,7 @@
           map (Pretty.quote o prt_term o Syntax.free) xs))];
 
     val (cs, xs) = foldl (FactIndex.index_term (is_known ctxt))
-      (([], []), map (read_term ctxt) ss);
+      (([], []), map (read_term_dummies ctxt) ss);
     val empty_idx = Library.null cs andalso Library.null xs;
 
     val header =

--- a/src/Pure/fact_index.ML	Tue Aug 27 17:24:41 2002 +0200
+++ b/src/Pure/fact_index.ML	Tue Aug 27 17:25:44 2002 +0200
@@ -29,7 +29,7 @@
   | add_frees _ (_, xs) = xs;
 
 fun index_term pred ((cs, xs), t) =
-  (Term.add_term_consts (t, cs), add_frees pred (t, xs));
+  (Term.add_term_consts (t, cs) \ Term.dummy_patternN, add_frees pred (t, xs));
 
 fun index_thm pred (idx, th) =
   let val {hyps, prop, ...} = Thm.rep_thm th