# HG changeset patch
# User wenzelm
# Date 1116773649 -7200
# Node ID f93ca3d4ffa75f4a45d318a21f23c3b2346c28ce
# Parent  bbc85a9748fcc1d4d2e4b6575d13a1595798e2b7
Retrieve theorems from proof context -- improved version of
  thms_containing by Rafal Kolanski, NICTA;

diff -r bbc85a9748fc -r f93ca3d4ffa7 src/Pure/Isar/find_theorems.ML
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Isar/find_theorems.ML	Sun May 22 16:54:09 2005 +0200
@@ -0,0 +1,243 @@
+(*  Title:      Pure/Isar/find_theorems.ML
+    ID:         $Id$
+    Author:     Rafal Kolanski, NICTA and Tobias Nipkow, TU Muenchen
+
+Retrieve theorems from proof context.
+*)
+
+val thms_containing_limit = ref 40;
+
+signature FIND_THEOREMS =
+sig
+  val find_thms: Proof.context -> FactIndex.spec -> (thmref * thm) list
+  val find_intros: Proof.context -> term -> (thmref * thm) list
+  val find_intros_goal: Proof.context -> thm -> int -> (thmref * thm) list
+  val find_elims: Proof.context -> term -> (thmref * thm) list
+  datatype search_criterion =
+    Name of string | Intro | Elim | Dest | Rewrite of string | Pattern of string
+  val print_theorems: Proof.context -> term option -> int option ->
+    (bool * search_criterion) list -> unit
+end;
+
+structure FindTheorems: FIND_THEOREMS =
+struct
+
+
+(* find_thms *)
+
+fun find_thms ctxt spec =
+  (PureThy.thms_containing (ProofContext.theory_of ctxt) spec @
+    ProofContext.lthms_containing ctxt spec)
+  |> map PureThy.selections |> List.concat;
+
+
+(* matching theorems *)
+
+local
+
+(*returns all those facts whose subterm extracted by extract can be
+  instantiated to obj; the list is sorted according to the number of premises
+  and the size of the required substitution*)
+fun select_match (extract_thms, extract_term) ctxt obj facts =
+  let
+    val match = #2 o Pattern.match (Sign.tsig_of (ProofContext.sign_of ctxt));
+
+    fun match_size pat =
+      let val subst = match (pat, obj)  (*exception Pattern.MATCH*)
+      in SOME (Vartab.foldl (op + o apsnd (Term.size_of_term o #2 o #2)) (0, subst)) end
+      handle Pattern.MATCH => NONE;
+
+    fun select (fact as (_, thm)) =
+      let
+        fun first_match (th :: ths) res =
+              (case match_size (extract_term (Thm.prop_of th)) of
+                SOME s => ((Thm.nprems_of th, s), fact) :: res
+              | NONE => first_match ths res)
+          | first_match [] res = res;
+      in first_match (extract_thms thm) end;
+
+    fun thm_ord (((p0, s0), _), ((p1, s1), _)) =
+      prod_ord (int_ord o pairself (fn 0 => 0 | x => 1)) int_ord ((p0, s0), (p1, s1));
+  in
+    fold select facts []
+    |> Library.sort thm_ord |> map #2
+  end;
+
+(*speed up retrieval by checking head symbol*)
+fun index_head ctxt prop =
+  (case Term.head_of (ObjectLogic.drop_judgment (ProofContext.sign_of ctxt) prop) of
+    Const (c, _) => ([c], [])
+  | Free (x, _) => if ProofContext.is_known ctxt x then ([], [x]) else ([], [])
+  | _ => ([], []));
+
+in
+
+fun find_matching_thms extract ctxt prop =
+  find_thms ctxt (index_head ctxt prop)
+  |> select_match extract ctxt prop;
+
+fun is_matching_thm extract ctxt prop fact =
+  not (null (select_match extract ctxt prop [fact]));
+
+end;
+
+
+(* intro/elim rules *)
+
+(*match statement against conclusion of some rule*)
+val find_intros =
+  find_matching_thms (single, Logic.strip_imp_concl);
+
+(*match conclusion of subgoal i against conclusion of some rule*)
+fun find_intros_goal ctxt st i =
+  find_intros ctxt (Logic.concl_of_goal (Thm.prop_of st) i);
+
+(*match statement against major premise of some rule*)
+val find_elims = find_matching_thms
+  (fn thm => if Thm.no_prems thm then [] else [thm],
+   hd o Logic.strip_imp_prems);
+
+
+
+(** search criteria **)
+
+datatype search_criterion =
+  Name of string | Intro | Elim | Dest | Rewrite of string | Pattern of string;
+
+fun string_of_crit (Name name) = "name: " ^ quote name
+  | string_of_crit Intro = "intro"
+  | string_of_crit Elim = "elim"
+  | string_of_crit Dest = "dest"
+  | string_of_crit (Rewrite s) = "rewrite: " ^ quote s
+  | string_of_crit (Pattern s) = quote s;
+
+fun string_of_criterion (b, c) = (if b then "" else "-") ^ string_of_crit c;
+
+
+
+(** search criterion filters **)
+
+(* filter_name *)
+
+fun is_substring pat str =
+  if String.size pat = 0 then true
+  else if String.size pat > String.size str then false
+  else if String.substring (str, 0, String.size pat) = pat then true
+  else is_substring pat (String.extract (str, 1, NONE));
+
+(*filter that just looks for a string in the name,
+  substring match only (no regexps are performed)*)
+fun filter_name str_pat ((name, _), _) = is_substring str_pat name;
+
+
+(* filter_intro *)
+
+(*checking conclusion of theorem against conclusion of goal*)
+fun filter_intro ctxt goal =
+  let
+    val extract_intro = (single, Logic.strip_imp_concl);
+    val concl = Logic.concl_of_goal goal 1;
+  in is_matching_thm extract_intro ctxt concl end;
+
+
+(* filter_elim_dest *)
+
+(*for elimination and destruction rules, we must check if the major
+  premise matches with one of the assumptions in the top subgoal, but
+  we must additionally make sure that we tell elim/dest apart, using
+  check_thm (cf. is_elim_rule below)*)
+fun filter_elim_dest check_thm ctxt goal =
+  let
+    val extract_elim =
+     (fn thm => if Thm.no_prems thm then [] else [thm],
+      hd o Logic.strip_imp_prems);
+
+    val prems = Logic.prems_of_goal goal 1;
+  in
+    fn fact => List.exists (fn prem =>
+      is_matching_thm extract_elim ctxt prem fact andalso check_thm (#2 fact)) prems
+  end;
+
+(*elimination rule: conclusion is a Var which does not appears in the
+  major premise*)
+fun is_elim_rule thm =
+  let
+    val prop = Thm.prop_of thm;
+    val concl = ObjectLogic.drop_judgment (Thm.sign_of_thm thm) (Logic.strip_imp_concl prop);
+    val major_prem = hd (Logic.strip_imp_prems prop);
+    val prem_vars = Drule.vars_of_terms [major_prem];
+  in
+    Term.is_Var concl andalso not (Term.dest_Var concl mem prem_vars)
+  end;
+
+
+(* filter_rewrite *)
+
+fun filter_rewrite ctxt str =
+  let
+    val (_, {mk_rews = {mk, ...}, ...}) =
+      MetaSimplifier.rep_ss (Simplifier.local_simpset_of ctxt);
+    val extract_rewrite = (mk, #1 o Logic.dest_equals o Logic.strip_imp_concl);
+  in is_matching_thm extract_rewrite ctxt (ProofContext.read_term ctxt str) end;
+
+
+(* filter_pattern *)
+
+(*subterm pattern supplied as raw string*)
+fun filter_pattern ctxt str =
+  let
+    val tsig = Sign.tsig_of (ProofContext.sign_of ctxt);
+    val [pat] = ProofContext.read_term_pats TypeInfer.logicT ctxt [str];
+  in fn (_, thm) => Pattern.matches_subterm tsig (pat, Thm.prop_of thm) end;
+
+
+(* interpret criteria as filters *)
+
+fun filter_crit _ _ (Name name) = filter_name name
+  | filter_crit ctxt _ (Rewrite str) = filter_rewrite ctxt str
+  | filter_crit ctxt _ (Pattern str) = filter_pattern ctxt str
+  (*beyond this point, only criteria requiring a goal!*)
+  | filter_crit _ NONE c =
+      error ("Need to have a current goal to use " ^ string_of_crit c)
+  | filter_crit ctxt (SOME goal) Intro = filter_intro ctxt goal
+  | filter_crit ctxt (SOME goal) Elim = filter_elim_dest is_elim_rule ctxt goal
+  | filter_crit ctxt (SOME goal) Dest =
+      filter_elim_dest (not o is_elim_rule) ctxt goal;
+      (*in this case all that is not elim is dest*)
+
+fun filter_criterion ctxt opt_goal (b, c) =
+  (if b then I else not) o filter_crit ctxt opt_goal c;
+
+fun all_filters filters = List.filter (fn x => List.all (fn f => f x) filters);
+
+
+(* print_theorems *)
+
+fun print_theorems ctxt opt_goal opt_limit criteria =
+  let
+    fun prt_fact (thmref, thm) =
+      ProofContext.pretty_fact ctxt (PureThy.string_of_thmref thmref, [thm]);
+    val prt_crit = Pretty.str o string_of_criterion;
+
+    val all_facts = find_thms ctxt ([], []);
+    val filters = map (filter_criterion ctxt opt_goal) criteria;
+    val matches = all_filters filters all_facts;
+
+    val len = length matches;
+    val limit = if_none opt_limit (! thms_containing_limit);
+    val count = Int.min (limit, len);
+
+    val pruned = len <= limit;
+    val found = "found " ^ string_of_int len ^ " theorems" ^
+      (if pruned then "" else " (" ^ string_of_int limit ^ " displayed)") ^ ":";
+  in
+    Pretty.big_list "searched for:" (map prt_crit criteria) ::
+     (if null matches then [Pretty.str "nothing found"]
+      else
+       [Pretty.str "", Pretty.str found] @
+       (if pruned then [] else [Pretty.str "..."]) @
+       map prt_fact (Library.drop (len - limit, matches)))
+    |> Pretty.chunks |> Pretty.writeln
+  end;
+
+end;