factored out derivation of induction principles, folds and recs, in preparation for reduction of nested to mutual
authorblanchet
Mon, 29 Apr 2013 10:37:23 +0200
changeset 51808 355dcd6a9b3c
parent 51805 67757f1d5e71
child 51809 d4c1abbb4095
factored out derivation of induction principles, folds and recs, in preparation for reduction of nested to mutual
src/HOL/BNF/Tools/bnf_fp_def_sugar.ML
--- a/src/HOL/BNF/Tools/bnf_fp_def_sugar.ML	Mon Apr 29 09:45:14 2013 +0200
+++ b/src/HOL/BNF/Tools/bnf_fp_def_sugar.ML	Mon Apr 29 10:37:23 2013 +0200
@@ -56,6 +56,8 @@
     let val (xs1, xs2, xs3, xs4) = split_list4 xs;
     in (x1 :: xs1, x2 :: xs2, x3 :: xs3, x4 :: xs4) end;
 
+fun exists_subtype_in Ts = exists_subtype (member (op =) Ts);
+
 fun resort_tfree S (TFree (s, _)) = TFree (s, S);
 
 fun typ_subst inst (T as Type (s, Ts)) =
@@ -155,6 +157,175 @@
 fun defaults_of ((_, ds), _) = ds;
 fun ctr_mixfix_of (_, mx) = mx;
 
+fun build_map lthy build_arg (Type (s, Ts)) (Type (_, Us)) =
+  let
+    val bnf = the (bnf_of lthy s);
+    val live = live_of_bnf bnf;
+    val mapx = mk_map live Ts Us (map_of_bnf bnf);
+    val TUs' = map dest_funT (fst (strip_typeN live (fastype_of mapx)));
+  in Term.list_comb (mapx, map build_arg TUs') end;
+
+fun build_rel_step lthy build_arg (Type (s, Ts)) =
+  let
+    val bnf = the (bnf_of lthy s);
+    val live = live_of_bnf bnf;
+    val rel = mk_rel live Ts Ts (rel_of_bnf bnf);
+    val Ts' = map domain_type (fst (strip_typeN live (fastype_of rel)));
+  in Term.list_comb (rel, map build_arg Ts') end;
+
+fun derive_induct_fold_rec_thms_for_types
+    nn fp_b_names pre_bnfs fp_induct fp_fold_thms fp_rec_thms nesting_bnfs nested_bnfs fpTs Cs
+    ctr_Tsss mss ns gss hss ((ctrss, xsss, ctr_defss, _), (folds, recs, fold_defs, rec_defs)) lthy =
+  let
+    val pre_map_defs = map map_def_of_bnf pre_bnfs;
+    val pre_set_defss = map set_defs_of_bnf pre_bnfs;
+    val nested_map_comp's = map map_comp'_of_bnf nested_bnfs;
+    val nested_map_ids'' = map (unfold_thms lthy @{thms id_def} o map_id_of_bnf) nested_bnfs;
+    val nesting_map_ids'' = map (unfold_thms lthy @{thms id_def} o map_id_of_bnf) nesting_bnfs;
+    val nested_set_map's = maps set_map'_of_bnf nested_bnfs;
+
+    val (((ps, ps'), us'), names_lthy) =
+      lthy
+      |> mk_Frees' "P" (map mk_pred1T fpTs)
+      ||>> Variable.variant_fixes fp_b_names;
+
+    val us = map2 (curry Free) us' fpTs;
+
+    fun mk_sets_nested bnf =
+      let
+        val Type (T_name, Us) = T_of_bnf bnf;
+        val lives = lives_of_bnf bnf;
+        val sets = sets_of_bnf bnf;
+        fun mk_set U =
+          (case find_index (curry (op =) U) lives of
+            ~1 => Term.dummy
+          | i => nth sets i);
+      in
+        (T_name, map mk_set Us)
+      end;
+
+    val setss_nested = map mk_sets_nested nested_bnfs;
+
+    val (induct_thms, induct_thm) =
+      let
+        fun mk_set Ts t =
+          let val Type (_, Ts0) = domain_type (fastype_of t) in
+            Term.subst_atomic_types (Ts0 ~~ Ts) t
+          end;
+
+        fun mk_raw_prem_prems names_lthy (x as Free (s, T as Type (T_name, Ts0))) =
+            (case find_index (curry (op =) T) fpTs of
+              ~1 =>
+              (case AList.lookup (op =) setss_nested T_name of
+                NONE => []
+              | SOME raw_sets0 =>
+                let
+                  val (Ts, raw_sets) =
+                    split_list (filter (exists_subtype_in fpTs o fst) (Ts0 ~~ raw_sets0));
+                  val sets = map (mk_set Ts0) raw_sets;
+                  val (ys, names_lthy') = names_lthy |> mk_Frees s Ts;
+                  val xysets = map (pair x) (ys ~~ sets);
+                  val ppremss = map (mk_raw_prem_prems names_lthy') ys;
+                in
+                  flat (map2 (map o apfst o cons) xysets ppremss)
+                end)
+            | kk => [([], (kk + 1, x))])
+          | mk_raw_prem_prems _ _ = [];
+
+        fun close_prem_prem xs t =
+          fold_rev Logic.all (map Free (drop (nn + length xs)
+            (rev (Term.add_frees t (map dest_Free xs @ ps'))))) t;
+
+        fun mk_prem_prem xs (xysets, (j, x)) =
+          close_prem_prem xs (Logic.list_implies (map (fn (x', (y, set)) =>
+              HOLogic.mk_Trueprop (HOLogic.mk_mem (y, set $ x'))) xysets,
+            HOLogic.mk_Trueprop (nth ps (j - 1) $ x)));
+
+        fun mk_raw_prem phi ctr ctr_Ts =
+          let
+            val (xs, names_lthy') = names_lthy |> mk_Frees "x" ctr_Ts;
+            val pprems = maps (mk_raw_prem_prems names_lthy') xs;
+          in (xs, pprems, HOLogic.mk_Trueprop (phi $ Term.list_comb (ctr, xs))) end;
+
+        fun mk_prem (xs, raw_pprems, concl) =
+          fold_rev Logic.all xs (Logic.list_implies (map (mk_prem_prem xs) raw_pprems, concl));
+
+        val raw_premss = map3 (map2 o mk_raw_prem) ps ctrss ctr_Tsss;
+
+        val goal =
+          Library.foldr (Logic.list_implies o apfst (map mk_prem)) (raw_premss,
+            HOLogic.mk_Trueprop (Library.foldr1 HOLogic.mk_conj (map2 (curry (op $)) ps us)));
+
+        val kksss = map (map (map (fst o snd) o #2)) raw_premss;
+
+        val ctor_induct' = fp_induct OF (map mk_sumEN_tupled_balanced mss);
+
+        val thm =
+          Goal.prove_sorry lthy [] [] goal (fn {context = ctxt, ...} =>
+            mk_induct_tac ctxt nn ns mss kksss (flat ctr_defss) ctor_induct' nested_set_map's
+              pre_set_defss)
+          |> singleton (Proof_Context.export names_lthy lthy)
+          |> Thm.close_derivation;
+      in
+        `(conj_dests nn) thm
+      end;
+
+    val induct_cases = quasi_unambiguous_case_names (maps (map name_of_ctr) ctrss);
+
+    val (fold_thmss, rec_thmss) =
+      let
+        val xctrss = map2 (map2 (curry Term.list_comb)) ctrss xsss;
+        val gfolds = map (lists_bmoc gss) folds;
+        val hrecs = map (lists_bmoc hss) recs;
+
+        fun mk_goal fss frec_like xctr f xs fxs =
+          fold_rev (fold_rev Logic.all) (xs :: fss)
+            (mk_Trueprop_eq (frec_like $ xctr, Term.list_comb (f, fxs)));
+
+        fun build_rec_like frec_likes (T, U) =
+          if T = U then
+            id_const T
+          else
+            (case find_index (curry (op =) T) fpTs of
+              ~1 => build_map lthy (build_rec_like frec_likes) T U
+            | kk => nth frec_likes kk);
+
+        val mk_U = typ_subst (map2 pair fpTs Cs);
+
+        fun unzip_rec_likes frec_likes combine (x as Free (_, T)) =
+          if exists_subtype_in fpTs T then
+            combine (x, build_rec_like frec_likes (T, mk_U T) $ x)
+          else
+            ([x], []);
+
+        val gxsss = map (map (flat_rec (unzip_rec_likes gfolds (fn (_, t) => ([t], []))))) xsss;
+        val hxsss = map (map (flat_rec (unzip_rec_likes hrecs (pairself single)))) xsss;
+
+        val fold_goalss = map5 (map4 o mk_goal gss) gfolds xctrss gss xsss gxsss;
+        val rec_goalss = map5 (map4 o mk_goal hss) hrecs xctrss hss xsss hxsss;
+
+        val fold_tacss =
+          map2 (map o mk_rec_like_tac pre_map_defs [] nesting_map_ids'' fold_defs) fp_fold_thms
+            ctr_defss;
+        val rec_tacss =
+          map2 (map o mk_rec_like_tac pre_map_defs nested_map_comp's
+            (nested_map_ids'' @ nesting_map_ids'') rec_defs) fp_rec_thms ctr_defss;
+
+        fun prove goal tac =
+          Goal.prove_sorry lthy [] [] goal (tac o #context)
+          |> Thm.close_derivation;
+      in
+        (map2 (map2 prove) fold_goalss fold_tacss, map2 (map2 prove) rec_goalss rec_tacss)
+      end;
+
+    val induct_case_names_attr = Attrib.internal (K (Rule_Cases.case_names induct_cases));
+    fun induct_type_attr T_name = Attrib.internal (K (Induct.induct_type T_name));
+  in
+    ((induct_thm, [induct_case_names_attr]),
+     (induct_thms, fn T_name => [induct_case_names_attr, induct_type_attr T_name]),
+     (fold_thmss, code_simp_attrs), (rec_thmss, code_simp_attrs))
+  end;
+
 fun define_datatypes prepare_constraint prepare_typ prepare_term lfp construct_fp
     (wrap_opts as (no_dests, rep_compat), specs) no_defs_lthy0 =
   let
@@ -264,22 +435,6 @@
 
     val timer = time (Timer.startRealTimer ());
 
-    fun build_map build_arg (Type (s, Ts)) (Type (_, Us)) =
-      let
-        val bnf = the (bnf_of lthy s);
-        val live = live_of_bnf bnf;
-        val mapx = mk_map live Ts Us (map_of_bnf bnf);
-        val TUs' = map dest_funT (fst (strip_typeN live (fastype_of mapx)));
-      in Term.list_comb (mapx, map build_arg TUs') end;
-
-    fun build_rel_step build_arg (Type (s, Ts)) =
-      let
-        val bnf = the (bnf_of lthy s);
-        val live = live_of_bnf bnf;
-        val rel = mk_rel live Ts Ts (rel_of_bnf bnf);
-        val Ts' = map domain_type (fst (strip_typeN live (fastype_of rel)));
-      in Term.list_comb (rel, map build_arg Ts') end;
-
     fun add_nesty_bnf_names Us =
       let
         fun add (Type (s, Ts)) ss =
@@ -332,9 +487,6 @@
             ((qualify true fp_b_name (Binding.name thmN), attrs T_name),
              [(thms, [])])) fp_b_names fpTs thmss);
 
-    val exists_fp_subtype = exists_subtype (member (op =) fpTs);
-    val exists_Cs_subtype = exists_subtype (member (op =) Cs);
-
     val ctr_Tsss = map (map (map (Term.typ_subst_atomic (Xs ~~ fpTs)))) ctr_TsssXs;
     val ns = map length ctr_Tsss;
     val kss = map (fn n => 1 upto n) ns;
@@ -368,7 +520,7 @@
             | proj_recT _ T = T;
 
           fun unzip_recT T =
-            if exists_fp_subtype T then ([proj_recT fst T], [proj_recT snd T]) else ([T], []);
+            if exists_subtype_in fpTs T then ([proj_recT fst T], [proj_recT snd T]) else ([T], []);
 
           val z_Tsss =
             map3 (fn n => fn ms => map2 dest_tupleT ms o dest_sumTN_balanced n o domain_type)
@@ -422,7 +574,7 @@
             | proj_corecT _ T = T;
 
           fun unzip_corecT T =
-            if exists_fp_subtype T then [proj_corecT fst T, proj_corecT snd T] else [T];
+            if exists_subtype_in fpTs T then [proj_corecT fst T, proj_corecT snd T] else [T];
 
           val (s_Tssss, h_sum_prod_Ts, h_Tsss, h_Tssss, ph_Tss) =
             mk_types unzip_corecT fp_rec_fun_Ts;
@@ -636,7 +788,7 @@
               else
                 (case (T, U) of
                   (Type (s, _), Type (s', _)) =>
-                  if s = s' then build_map (build_prod_proj mk_proj) T U else mk_proj T
+                  if s = s' then build_map lthy (build_prod_proj mk_proj) T U else mk_proj T
                 | _ => mk_proj T);
 
             (* TODO: Avoid these complications; cf. corec case *)
@@ -646,7 +798,7 @@
               | mk_U _ T = T;
 
             fun unzip_rec (x as Free (_, T)) =
-              if exists_fp_subtype T then
+              if exists_subtype_in fpTs T then
                 ([build_prod_proj fst_const (T, mk_U fst T) $ x],
                  [build_prod_proj snd_const (T, mk_U snd T) $ x])
               else
@@ -696,7 +848,7 @@
               else
                 (case (T, U) of
                   (Type (s, _), Type (s', _)) =>
-                  if s = s' then build_map (build_sum_inj mk_inj) T U
+                  if s = s' then build_map lthy (build_sum_inj mk_inj) T U
                   else uncurry mk_inj (dest_sumT U)
                 | _ => uncurry mk_inj (dest_sumT U));
 
@@ -761,165 +913,31 @@
       map3 (fn (_, _, _, injects, distincts, cases, _, _, _) => fn rec_likes => fn fold_likes =>
         injects @ distincts @ cases @ rec_likes @ fold_likes);
 
-    fun derive_induct_fold_rec_thms_for_types (((ctrss, xsss, ctr_defss, wrap_ress), (folds, recs,
-        fold_defs, rec_defs)), lthy) =
+    fun derive_and_note_induct_fold_rec_thms_for_types (info as ((_, _, _, wrap_ress), _), lthy) =
       let
-        val (((ps, ps'), us'), names_lthy) =
-          lthy
-          |> mk_Frees' "P" (map mk_pred1T fpTs)
-          ||>> Variable.variant_fixes fp_b_names;
-
-        val us = map2 (curry Free) us' fpTs;
-
-        fun mk_sets_nested bnf =
-          let
-            val Type (T_name, Us) = T_of_bnf bnf;
-            val lives = lives_of_bnf bnf;
-            val sets = sets_of_bnf bnf;
-            fun mk_set U =
-              (case find_index (curry (op =) U) lives of
-                ~1 => Term.dummy
-              | i => nth sets i);
-          in
-            (T_name, map mk_set Us)
-          end;
-
-        val setss_nested = map mk_sets_nested nested_bnfs;
-
-        val (induct_thms, induct_thm) =
-          let
-            fun mk_set Ts t =
-              let val Type (_, Ts0) = domain_type (fastype_of t) in
-                Term.subst_atomic_types (Ts0 ~~ Ts) t
-              end;
-
-            fun mk_raw_prem_prems names_lthy (x as Free (s, T as Type (T_name, Ts0))) =
-                (case find_index (curry (op =) T) fpTs of
-                  ~1 =>
-                  (case AList.lookup (op =) setss_nested T_name of
-                    NONE => []
-                  | SOME raw_sets0 =>
-                    let
-                      val (Ts, raw_sets) =
-                        split_list (filter (exists_fp_subtype o fst) (Ts0 ~~ raw_sets0));
-                      val sets = map (mk_set Ts0) raw_sets;
-                      val (ys, names_lthy') = names_lthy |> mk_Frees s Ts;
-                      val xysets = map (pair x) (ys ~~ sets);
-                      val ppremss = map (mk_raw_prem_prems names_lthy') ys;
-                    in
-                      flat (map2 (map o apfst o cons) xysets ppremss)
-                    end)
-                | kk => [([], (kk + 1, x))])
-              | mk_raw_prem_prems _ _ = [];
-
-            fun close_prem_prem xs t =
-              fold_rev Logic.all (map Free (drop (nn + length xs)
-                (rev (Term.add_frees t (map dest_Free xs @ ps'))))) t;
-
-            fun mk_prem_prem xs (xysets, (j, x)) =
-              close_prem_prem xs (Logic.list_implies (map (fn (x', (y, set)) =>
-                  HOLogic.mk_Trueprop (HOLogic.mk_mem (y, set $ x'))) xysets,
-                HOLogic.mk_Trueprop (nth ps (j - 1) $ x)));
-
-            fun mk_raw_prem phi ctr ctr_Ts =
-              let
-                val (xs, names_lthy') = names_lthy |> mk_Frees "x" ctr_Ts;
-                val pprems = maps (mk_raw_prem_prems names_lthy') xs;
-              in (xs, pprems, HOLogic.mk_Trueprop (phi $ Term.list_comb (ctr, xs))) end;
-
-            fun mk_prem (xs, raw_pprems, concl) =
-              fold_rev Logic.all xs (Logic.list_implies (map (mk_prem_prem xs) raw_pprems, concl));
-
-            val raw_premss = map3 (map2 o mk_raw_prem) ps ctrss ctr_Tsss;
-
-            val goal =
-              Library.foldr (Logic.list_implies o apfst (map mk_prem)) (raw_premss,
-                HOLogic.mk_Trueprop (Library.foldr1 HOLogic.mk_conj (map2 (curry (op $)) ps us)));
-
-            val kksss = map (map (map (fst o snd) o #2)) raw_premss;
-
-            val ctor_induct' = fp_induct OF (map mk_sumEN_tupled_balanced mss);
-
-            val thm =
-              Goal.prove_sorry lthy [] [] goal (fn {context = ctxt, ...} =>
-                mk_induct_tac ctxt nn ns mss kksss (flat ctr_defss) ctor_induct' nested_set_map's
-                  pre_set_defss)
-              |> singleton (Proof_Context.export names_lthy lthy)
-              |> Thm.close_derivation;
-          in
-            `(conj_dests nn) thm
-          end;
-
-        val induct_cases = quasi_unambiguous_case_names (maps (map name_of_ctr) ctrss);
-
-        val (fold_thmss, rec_thmss) =
-          let
-            val xctrss = map2 (map2 (curry Term.list_comb)) ctrss xsss;
-            val gfolds = map (lists_bmoc gss) folds;
-            val hrecs = map (lists_bmoc hss) recs;
-
-            fun mk_goal fss frec_like xctr f xs fxs =
-              fold_rev (fold_rev Logic.all) (xs :: fss)
-                (mk_Trueprop_eq (frec_like $ xctr, Term.list_comb (f, fxs)));
-
-            fun build_rec_like frec_likes (T, U) =
-              if T = U then
-                id_const T
-              else
-                (case find_index (curry (op =) T) fpTs of
-                  ~1 => build_map (build_rec_like frec_likes) T U
-                | kk => nth frec_likes kk);
-
-            val mk_U = typ_subst (map2 pair fpTs Cs);
-
-            fun unzip_rec_likes frec_likes combine (x as Free (_, T)) =
-              if exists_fp_subtype T then
-                combine (x, build_rec_like frec_likes (T, mk_U T) $ x)
-              else
-                ([x], []);
-
-            val gxsss = map (map (flat_rec (unzip_rec_likes gfolds (fn (_, t) => ([t], []))))) xsss;
-            val hxsss = map (map (flat_rec (unzip_rec_likes hrecs (pairself single)))) xsss;
-
-            val fold_goalss = map5 (map4 o mk_goal gss) gfolds xctrss gss xsss gxsss;
-            val rec_goalss = map5 (map4 o mk_goal hss) hrecs xctrss hss xsss hxsss;
-
-            val fold_tacss =
-              map2 (map o mk_rec_like_tac pre_map_defs [] nesting_map_ids'' fold_defs) fp_fold_thms
-                ctr_defss;
-            val rec_tacss =
-              map2 (map o mk_rec_like_tac pre_map_defs nested_map_comp's
-                (nested_map_ids'' @ nesting_map_ids'') rec_defs) fp_rec_thms ctr_defss;
-
-            fun prove goal tac =
-              Goal.prove_sorry lthy [] [] goal (tac o #context)
-              |> Thm.close_derivation;
-          in
-            (map2 (map2 prove) fold_goalss fold_tacss, map2 (map2 prove) rec_goalss rec_tacss)
-          end;
+        val ((induct_thm, induct_attrs), (induct_thms, inducts_attrs), (fold_thmss, fold_attrs),
+             (rec_thmss, rec_attrs)) =
+          derive_induct_fold_rec_thms_for_types nn fp_b_names pre_bnfs fp_induct fp_fold_thms
+            fp_rec_thms nesting_bnfs nested_bnfs fpTs Cs ctr_Tsss mss ns gss hss info lthy;
 
         val simp_thmss = mk_simp_thmss wrap_ress rec_thmss fold_thmss;
 
-        val induct_case_names_attr = Attrib.internal (K (Rule_Cases.case_names induct_cases));
-        fun induct_type_attr T_name = Attrib.internal (K (Induct.induct_type T_name));
-
         val common_notes =
-          (if nn > 1 then [(inductN, [induct_thm], [induct_case_names_attr])] else [])
+          (if nn > 1 then [(inductN, [induct_thm], induct_attrs)] else [])
           |> massage_simple_notes fp_common_name;
 
         val notes =
-          [(foldN, fold_thmss, K code_simp_attrs),
-           (inductN, map single induct_thms,
-            fn T_name => [induct_case_names_attr, induct_type_attr T_name]),
-           (recN, rec_thmss, K code_simp_attrs),
+          [(foldN, fold_thmss, K fold_attrs),
+           (inductN, map single induct_thms, inducts_attrs),
+           (recN, rec_thmss, K rec_attrs),
            (simpsN, simp_thmss, K [])]
           |> massage_multi_notes;
       in
         lthy |> Local_Theory.notes (common_notes @ notes) |> snd
       end;
 
-    fun derive_coinduct_unfold_corec_thms_for_types (((ctrss, _, ctr_defss, wrap_ress), (unfolds,
-        corecs, unfold_defs, corec_defs)), lthy) =
+    fun derive_and_note_coinduct_unfold_corec_thms_for_types (((ctrss, _, ctr_defss, wrap_ress),
+        (unfolds, corecs, unfold_defs, corec_defs)), lthy) =
       let
         val nesting_rel_eqs = map rel_eq_of_bnf nesting_bnfs;
 
@@ -955,7 +973,8 @@
             fun build_rel rs' T =
               (case find_index (curry (op =) T) fpTs of
                 ~1 =>
-                if exists_fp_subtype T then build_rel_step (build_rel rs') T else HOLogic.eq_const T
+                if exists_subtype_in fpTs T then build_rel_step lthy (build_rel rs') T
+                else HOLogic.eq_const T
               | kk => nth rs' kk);
 
             fun build_rel_app rs' usel vsel =
@@ -1039,14 +1058,15 @@
                 id_const T
               else
                 (case find_index (curry (op =) U) fpTs of
-                  ~1 => build_map (build_corec_like fcorec_likes) T U
+                  ~1 => build_map lthy (build_corec_like fcorec_likes) T U
                 | kk => nth fcorec_likes kk);
 
             val mk_U = typ_subst (map2 pair Cs fpTs);
 
             fun intr_corec_likes fcorec_likes [] [cf] =
                 let val T = fastype_of cf in
-                  if exists_Cs_subtype T then build_corec_like fcorec_likes (T, mk_U T) $ cf else cf
+                  if exists_subtype_in Cs T then build_corec_like fcorec_likes (T, mk_U T) $ cf
+                  else cf
                 end
               | intr_corec_likes fcorec_likes [cq] [cf, cf'] =
                 mk_If cq (intr_corec_likes fcorec_likes [] [cf])
@@ -1211,8 +1231,8 @@
         mss ~~ ctr_bindingss ~~ ctr_mixfixess ~~ ctr_Tsss ~~ disc_bindingss ~~ sel_bindingsss ~~
         raw_sel_defaultsss)
       |> wrap_types_and_more
-      |> (if lfp then derive_induct_fold_rec_thms_for_types
-          else derive_coinduct_unfold_corec_thms_for_types);
+      |> (if lfp then derive_and_note_induct_fold_rec_thms_for_types
+          else derive_and_note_coinduct_unfold_corec_thms_for_types);
 
     val timer = time (timer ("Constructors, discriminators, selectors, etc., for the new " ^
       (if lfp then "" else "co") ^ "datatype"));