added add_local/add_global;
index props (for add_local only);
added could_unify;

--- a/src/Pure/fact_index.ML	Fri Oct 28 22:27:52 2005 +0200
+++ b/src/Pure/fact_index.ML	Fri Oct 28 22:27:54 2005 +0200
@@ -8,62 +8,75 @@
 signature FACT_INDEX =
 sig
   type spec
-  val index_term: (string -> bool) -> term -> spec -> spec
-  val index_thm: (string -> bool) -> thm -> spec -> spec
   type T
   val facts: T -> (string * thm list) list
+  val could_unify: T -> term -> thm list
   val empty: T
-  val add: (string -> bool) -> (string * thm list) -> T -> T
+  val add_global: (string * thm list) -> T -> T
+  val add_local: (string -> bool) -> (string * thm list) -> T -> T
   val find: T -> spec -> (string * thm list) list
 end;
 
 structure FactIndex: FACT_INDEX =
 struct
 
-type spec = string list * string list;
-
 
 (* indexing items *)
 
+type spec = string list * string list;
+
 val add_consts = fold_aterms
   (fn Const (c, _) => if c = Term.dummy_patternN then I else insert (op =) c | _ => I);
 
-fun add_frees pred = fold_aterms
-  (fn Free (x, _) => if pred x then insert (op =) x else I | _ => I);
+fun add_frees known = fold_aterms
+  (fn Free (x, _) => if known x then insert (op =) x else I | _ => I);
 
-fun index_term pred t (cs, xs) = (add_consts t cs, add_frees pred t xs);
+fun index_term known t (cs, xs) = (add_consts t cs, add_frees known t xs);
 
-fun index_thm pred th idx =
+fun index_thm known th idx =
   let val {tpairs, hyps, prop, ...} = Thm.rep_thm th in
     idx
-    |> index_term pred prop
-    |> fold (index_term pred) hyps
-    |> fold (fn (t, u) => index_term pred t #> index_term pred u) tpairs
+    |> index_term known prop
+    |> fold (index_term known) hyps
+    |> fold (fn (t, u) => index_term known t #> index_term known u) tpairs
   end;
 
 
 (* build index *)
 
-datatype T = Index of {next: int, facts: (string * thm list) list,
-  consts: (int * (string * thm list)) list Symtab.table,
-  frees: (int * (string * thm list)) list Symtab.table};
+type fact = string * thm list;
+
+datatype T = Index of
+ {facts: fact list,
+  consts: (serial * fact) list Symtab.table,
+  frees: (serial * fact) list Symtab.table,
+  props: thm Net.net};
 
 fun facts (Index {facts, ...}) = facts;
+fun could_unify (Index {props, ...}) = Net.unify_term props;
 
 val empty =
-  Index {next = 0, facts = [], consts = Symtab.empty, frees = Symtab.empty};
+  Index {facts = [], consts = Symtab.empty, frees = Symtab.empty, props = Net.empty};
 
-fun add pred (name, ths) (Index {next, facts, consts, frees}) =
+fun add do_props known (fact as (_, ths)) (Index {facts, consts, frees, props}) =
   let
-    fun upd a = Symtab.update_multi (a, (next, (name, ths)));
-    val (cs, xs) = fold (index_thm pred) ths ([], []);
-  in
-    Index {next = next + 1, facts = (name, ths) :: facts,
-      consts = fold upd cs consts, frees = fold upd xs frees}
-  end;
+    val entry = (serial (), fact);
+    val (cs, xs) = fold (index_thm known) ths ([], []);
+
+    val facts' = fact :: facts;
+    val consts' = consts |> fold (fn c => Symtab.update_multi (c, entry)) cs;
+    val frees' = frees |> fold (fn x => Symtab.update_multi (x, entry)) xs;
+    val props' = props |> K do_props ?
+      fold (fn th => Net.insert_term (K false) (Thm.prop_of th, th)) ths;
+  in Index {facts = facts', consts = consts', frees = frees', props = props'} end;
+
+val add_global = add false (K false);
+val add_local = add true;
 
 
-(* find facts *)
+(* find by consts/frees *)
+
+local
 
 fun fact_ord ((i, _), (j, _)) = int_ord (j, i);
 
@@ -72,9 +85,13 @@
       if exists null xss then []
       else fold (OrdList.inter fact_ord) (tl xss) (hd xss);
 
+in
+
 fun find idx ([], []) = facts idx
   | find (Index {consts, frees, ...}) (cs, xs) =
       (map (Symtab.lookup_multi consts) cs @
         map (Symtab.lookup_multi frees) xs) |> intersects |> map #2;
 
+end
+
 end;