# HG changeset patch # User berghofe # Date 1184147011 -7200 # Node ID 15f81c5d53309bf7e83a2d8f3c3983105ac6dc9b # Parent b136b53fcd2ae580b5e6f68c3bcdd863219f106e New wrapper for defining inductive sets with new inductive predicate package. diff -r b136b53fcd2a -r 15f81c5d5330 src/HOL/Tools/inductive_set_package.ML --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/HOL/Tools/inductive_set_package.ML Wed Jul 11 11:43:31 2007 +0200 @@ -0,0 +1,542 @@ +(* Title: HOL/Tools/inductive_set_package.ML + ID: $Id$ + Author: Stefan Berghofer, TU Muenchen + +Wrapper for defining inductive sets using package for inductive predicates, +including infrastructure for converting between predicates and sets. +*) + +signature INDUCTIVE_SET_PACKAGE = +sig + val to_set_att: thm list -> attribute + val to_pred_att: thm list -> attribute + val pred_set_conv_att: attribute + val add_inductive_i: bool -> bstring -> bool -> bool -> bool -> + (string * typ option * mixfix) list -> + (string * typ option) list -> ((bstring * Attrib.src list) * term) list -> thm list -> + local_theory -> InductivePackage.inductive_result * local_theory + val add_inductive: bool -> bool -> (string * string option * mixfix) list -> + (string * string option * mixfix) list -> + ((bstring * Attrib.src list) * string) list -> (thmref * Attrib.src list) list -> + local_theory -> InductivePackage.inductive_result * local_theory + val setup: theory -> theory +end; + +structure InductiveSetPackage: INDUCTIVE_SET_PACKAGE = +struct + +val note_theorem = LocalTheory.note Thm.theoremK; + + +(**** simplify {(x1, ..., xn). (x1, ..., xn) : S} to S ****) + +val subset_antisym = thm "subset_antisym"; + +val collect_mem_simproc = + Simplifier.simproc (theory "Set") "Collect_mem" ["Collect t"] (fn thy => fn ss => + fn S as Const ("Collect", Type ("fun", [_, T])) $ t => + let val (u, Ts, ps) = HOLogic.strip_split t + in case u of + (c as Const ("op :", _)) $ q $ S' => + (case try (HOLogic.dest_tuple' ps) q of + NONE => NONE + | SOME ts => + if not (loose_bvar (S', 0)) andalso + ts = map Bound (length ps downto 0) + then + let val simp = full_simp_tac (Simplifier.inherit_context ss + (HOL_basic_ss addsimps [split_paired_all, split_conv])) 1 + in + SOME (Goal.prove (Simplifier.the_context ss) [] [] + (Const ("==", T --> T --> propT) $ S $ S') + (K (EVERY + [rtac eq_reflection 1, rtac subset_antisym 1, + rtac subsetI 1, dtac CollectD 1, simp, + rtac subsetI 1, rtac CollectI 1, simp]))) + end + else NONE) + | _ => NONE + end + | _ => NONE); + +(***********************************************************************************) +(* simplifies (%x y. (x, y) : S & P x y) to (%x y. (x, y) : S Int {(x, y). P x y}) *) +(* and (%x y. (x, y) : S | P x y) to (%x y. (x, y) : S Un {(x, y). P x y}) *) +(* used for converting "strong" (co)induction rules *) +(***********************************************************************************) + +val strong_ind_simproc = + Simplifier.simproc HOL.thy "strong_ind" ["t"] (fn thy => fn ss => fn t => + let + val xs = strip_abs_vars t; + fun close t = fold (fn x => fn u => all (fastype_of x) $ lambda x u) + (term_vars t) t; + fun mkop "op &" T x = SOME (Const ("op Int", T --> T --> T), x) + | mkop "op |" T x = SOME (Const ("op Un", T --> T --> T), x) + | mkop _ _ _ = NONE; + fun mk_collect p T t = + let val U = HOLogic.dest_setT T + in HOLogic.Collect_const U $ + HOLogic.ap_split' (HOLogic.prod_factors p) U HOLogic.boolT t + end; + fun decomp (Const (s, _) $ ((m as Const ("op :", + Type (_, [_, Type (_, [T, _])]))) $ p $ S) $ u) = + mkop s T (m, p, S, mk_collect p T (head_of u)) + | decomp (Const (s, _) $ u $ ((m as Const ("op :", + Type (_, [_, Type (_, [T, _])]))) $ p $ S)) = + mkop s T (m, p, mk_collect p T (head_of u), S) + | decomp _ = NONE; + val simp = full_simp_tac (Simplifier.inherit_context ss + (HOL_basic_ss addsimps [mem_Collect_eq, split_conv])) 1; + in + if null xs then NONE + else case decomp (strip_abs_body t) of + NONE => NONE + | SOME (bop, (m, p, S, S')) => + SOME (mk_meta_eq (Goal.prove (Simplifier.the_context ss) [] [] + (close (HOLogic.mk_Trueprop (HOLogic.mk_eq + (t, list_abs (xs, m $ p $ (bop $ S $ S')))))) + (K (EVERY + [REPEAT (rtac ext 1), rtac iffI 1, + EVERY [etac conjE 1, rtac IntI 1, simp, simp, + etac IntE 1, rtac conjI 1, simp, simp] ORELSE + EVERY [etac disjE 1, rtac UnI1 1, simp, rtac UnI2 1, simp, + etac UnE 1, rtac disjI1 1, simp, rtac disjI2 1, simp]])))) + handle ERROR _ => NONE + end); + +(* only eta contract terms occurring as arguments of functions satisfying p *) +fun eta_contract p = + let + fun eta b (Abs (a, T, body)) = + (case eta b body of + body' as (f $ Bound 0) => + if loose_bvar1 (f, 0) orelse not b then Abs (a, T, body') + else incr_boundvars ~1 f + | body' => Abs (a, T, body')) + | eta b (t $ u) = eta b t $ eta (p (head_of t)) u + | eta b t = t + in eta false end; + +fun eta_contract_thm p = + Conv.fconv_rule (Conv.then_conv (Thm.beta_conversion true, fn ct => + Thm.transitive (Thm.eta_conversion ct) + (Thm.symmetric (Thm.eta_conversion + (cterm_of (theory_of_cterm ct) (eta_contract p (term_of ct))))))); + + +(***********************************************************) +(* rules for converting between predicate and set notation *) +(* *) +(* rules for converting predicates to sets have the form *) +(* P (%x y. (x, y) : s) = (%x y. (x, y) : S s) *) +(* *) +(* rules for converting sets to predicates have the form *) +(* S {(x, y). p x y} = {(x, y). P p x y} *) +(* *) +(* where s and p are parameters *) +(***********************************************************) + +structure PredSetConvData = GenericDataFun +( + type T = + {(* rules for converting predicates to sets *) + to_set_simps: thm list, + (* rules for converting sets to predicates *) + to_pred_simps: thm list, + (* arities of functions of type t set => ... => u set *) + set_arities: (typ * (int list list option list * int list list option)) list Symtab.table, + (* arities of functions of type (t => ... => bool) => u => ... => bool *) + pred_arities: (typ * (int list list option list * int list list option)) list Symtab.table}; + val empty = {to_set_simps = [], to_pred_simps = [], + set_arities = Symtab.empty, pred_arities = Symtab.empty}; + val extend = I; + fun merge _ + ({to_set_simps = to_set_simps1, to_pred_simps = to_pred_simps1, + set_arities = set_arities1, pred_arities = pred_arities1}, + {to_set_simps = to_set_simps2, to_pred_simps = to_pred_simps2, + set_arities = set_arities2, pred_arities = pred_arities2}) = + {to_set_simps = Drule.merge_rules (to_set_simps1, to_set_simps2), + to_pred_simps = Drule.merge_rules (to_pred_simps1, to_pred_simps2), + set_arities = Symtab.merge_list op = (set_arities1, set_arities2), + pred_arities = Symtab.merge_list op = (pred_arities1, pred_arities2)}; +); + +fun name_type_of (Free p) = SOME p + | name_type_of (Const p) = SOME p + | name_type_of _ = NONE; + +fun map_type f (Free (s, T)) = Free (s, f T) + | map_type f (Var (ixn, T)) = Var (ixn, f T) + | map_type f _ = error "map_type"; + +fun find_most_specific is_inst f eq xs T = + find_first (fn U => is_inst (T, f U) + andalso forall (fn U' => eq (f U, f U') orelse not + (is_inst (T, f U') andalso is_inst (f U', f U))) + xs) xs; + +fun lookup_arity thy arities (s, T) = case Symtab.lookup arities s of + NONE => NONE + | SOME xs => find_most_specific (Sign.typ_instance thy) fst (op =) xs T; + +fun lookup_rule thy f rules = find_most_specific + (swap #> Pattern.matches thy) (f #> fst) (op aconv) rules; + +fun infer_arities thy arities (optf, t) fs = case strip_comb t of + (Abs (s, T, u), []) => infer_arities thy arities (NONE, u) fs + | (Abs _, _) => infer_arities thy arities (NONE, Envir.beta_norm t) fs + | (u, ts) => (case Option.map (lookup_arity thy arities) (name_type_of u) of + SOME (SOME (_, (arity, _))) => + (fold (infer_arities thy arities) (arity ~~ List.take (ts, length arity)) fs + handle Subscript => error "infer_arities: bad term") + | _ => fold (infer_arities thy arities) (map (pair NONE) ts) + (case optf of + NONE => fs + | SOME f => AList.update op = (u, the_default f + (Option.map (curry op inter f) (AList.lookup op = fs u))) fs)); + + +(**************************************************************) +(* derive the to_pred equation from the to_set equation *) +(* *) +(* 1. instantiate each set parameter with {(x, y). p x y} *) +(* 2. apply %P. {(x, y). P x y} to both sides of the equation *) +(* 3. simplify *) +(**************************************************************) + +fun mk_to_pred_inst thy fs = + map (fn (x, ps) => + let + val U = HOLogic.dest_setT (fastype_of x); + val x' = map_type (K (HOLogic.prodT_factors' ps U ---> HOLogic.boolT)) x + in + (cterm_of thy x, + cterm_of thy (HOLogic.Collect_const U $ + HOLogic.ap_split' ps U HOLogic.boolT x')) + end) fs; + +fun mk_to_pred_eq p fs optfs' T thm = + let + val thy = theory_of_thm thm; + val insts = mk_to_pred_inst thy fs; + val thm' = Thm.instantiate ([], insts) thm; + val thm'' = (case optfs' of + NONE => thm' RS sym + | SOME fs' => + let + val U = HOLogic.dest_setT (body_type T); + val Ts = HOLogic.prodT_factors' fs' U; + (* FIXME: should cterm_instantiate increment indexes? *) + val arg_cong' = Thm.incr_indexes (Thm.maxidx_of thm + 1) arg_cong; + val (arg_cong_f, _) = arg_cong' |> cprop_of |> Drule.strip_imp_concl |> + Thm.dest_comb |> snd |> Drule.strip_comb |> snd |> hd |> Thm.dest_comb + in + thm' RS (Drule.cterm_instantiate [(arg_cong_f, + cterm_of thy (Abs ("P", Ts ---> HOLogic.boolT, + HOLogic.Collect_const U $ HOLogic.ap_split' fs' U + HOLogic.boolT (Bound 0))))] arg_cong' RS sym) + end) + in + Simplifier.simplify (HOL_basic_ss addsimps [mem_Collect_eq, split_conv] + addsimprocs [collect_mem_simproc]) thm'' |> + zero_var_indexes |> eta_contract_thm (equal p) + end; + + +(**** declare rules for converting predicates to sets ****) + +fun add ctxt thm {to_set_simps, to_pred_simps, set_arities, pred_arities} = + case prop_of thm of + Const ("Trueprop", _) $ (Const ("op =", Type (_, [T, _])) $ lhs $ rhs) => + (case body_type T of + Type ("bool", []) => + let + val thy = Context.theory_of ctxt; + fun factors_of t fs = case strip_abs_body t of + Const ("op :", _) $ u $ S => + if is_Free S orelse is_Var S then + let val ps = HOLogic.prod_factors u + in (SOME ps, (S, ps) :: fs) end + else (NONE, fs) + | _ => (NONE, fs); + val (h, ts) = strip_comb lhs + val (pfs, fs) = fold_map factors_of ts []; + val ((h', ts'), fs') = (case rhs of + Abs _ => (case strip_abs_body rhs of + Const ("op :", _) $ u $ S => + (strip_comb S, SOME (HOLogic.prod_factors u)) + | _ => error "member symbol on right-hand side expected") + | _ => (strip_comb rhs, NONE)) + in + case (name_type_of h, name_type_of h') of + (SOME (s, T), SOME (s', T')) => + (case Symtab.lookup set_arities s' of + NONE => () + | SOME xs => if exists (fn (U, _) => + Sign.typ_instance thy (T', U) andalso + Sign.typ_instance thy (U, T')) xs + then + error ("Clash of conversion rules for operator " ^ s') + else (); + {to_set_simps = thm :: to_set_simps, + to_pred_simps = + mk_to_pred_eq h fs fs' T' thm :: to_pred_simps, + set_arities = Symtab.insert_list op = (s', + (T', (map (AList.lookup op = fs) ts', fs'))) set_arities, + pred_arities = Symtab.insert_list op = (s, + (T, (pfs, fs'))) pred_arities}) + | _ => error "set / predicate constant expected" + end + | _ => error "equation between predicates expected") + | _ => error "equation expected"; + +val pred_set_conv_att = Thm.declaration_attribute + (fn thm => fn ctxt => PredSetConvData.map (add ctxt thm) ctxt); + + +(**** convert theorem in set notation to predicate notation ****) + +fun is_pred tab t = + case Option.map (Symtab.lookup tab o fst) (name_type_of t) of + SOME (SOME _) => true | _ => false; + +fun to_pred_simproc rules = + let val rules' = map mk_meta_eq rules + in + Simplifier.simproc HOL.thy "to_pred" ["t"] + (fn thy => K (lookup_rule thy (prop_of #> Logic.dest_equals) rules')) + end; + +fun to_pred_proc thy rules t = case lookup_rule thy I rules t of + NONE => NONE + | SOME (lhs, rhs) => + SOME (Envir.subst_vars + (Pattern.match thy (lhs, t) (Vartab.empty, Vartab.empty)) rhs); + +fun to_pred thms ctxt thm = + let + val thy = Context.theory_of ctxt; + val {to_pred_simps, set_arities, pred_arities, ...} = + fold (add ctxt) thms (PredSetConvData.get ctxt); + val fs = filter (is_Var o fst) + (infer_arities thy set_arities (NONE, prop_of thm) []); + (* instantiate each set parameter with {(x, y). p x y} *) + val insts = mk_to_pred_inst thy fs + in + thm |> + Thm.instantiate ([], insts) |> + Simplifier.full_simplify (HOL_basic_ss addsimprocs + [to_pred_simproc (mem_Collect_eq :: split_conv :: to_pred_simps)]) |> + eta_contract_thm (is_pred pred_arities) + end; + +val to_pred_att = Thm.rule_attribute o to_pred; + + +(**** convert theorem in predicate notation to set notation ****) + +fun to_set thms ctxt thm = + let + val thy = Context.theory_of ctxt; + val {to_set_simps, pred_arities, ...} = + fold (add ctxt) thms (PredSetConvData.get ctxt); + val fs = filter (is_Var o fst) + (infer_arities thy pred_arities (NONE, prop_of thm) []); + (* instantiate each predicate parameter with %x y. (x, y) : s *) + val insts = map (fn (x, ps) => + let + val Ts = binder_types (fastype_of x); + val T = HOLogic.mk_tupleT ps Ts; + val x' = map_type (K (HOLogic.mk_setT T)) x + in + (cterm_of thy x, + cterm_of thy (list_abs (map (pair "x") Ts, HOLogic.mk_mem + (HOLogic.mk_tuple' ps T (map Bound (length ps downto 0)), x')))) + end) fs + in + Simplifier.full_simplify (HOL_basic_ss addsimps to_set_simps + addsimprocs [strong_ind_simproc]) + (Thm.instantiate ([], insts) thm) + end; + +val to_set_att = Thm.rule_attribute o to_set; + + +(**** preprocessor for code generator ****) + +fun codegen_preproc thy = + let + val {to_pred_simps, set_arities, pred_arities, ...} = + PredSetConvData.get (Context.Theory thy); + fun preproc thm = + if exists_Const (fn (s, _) => case Symtab.lookup set_arities s of + NONE => false + | SOME arities => exists (fn (_, (xs, _)) => + forall is_none xs) arities) (prop_of thm) + then + thm |> + Simplifier.full_simplify (HOL_basic_ss addsimprocs + [to_pred_simproc (mem_Collect_eq :: split_conv :: to_pred_simps)]) |> + eta_contract_thm (is_pred pred_arities) + else thm + in map preproc end; + +fun code_ind_att optmod = to_pred_att [] #> InductiveCodegen.add optmod NONE; + + +(**** definition of inductive sets ****) + +fun add_ind_set_def verbose alt_name coind no_elim no_ind cs + intros monos params cnames_syn ctxt = + let + val thy = ProofContext.theory_of ctxt; + val {set_arities, pred_arities, to_pred_simps, ...} = + PredSetConvData.get (Context.Proof ctxt); + fun infer (Abs (_, _, t)) = infer t + | infer (Const ("op :", _) $ t $ u) = + infer_arities thy set_arities (SOME (HOLogic.prod_factors t), u) + | infer (t $ u) = infer t #> infer u + | infer _ = I; + val new_arities = filter_out + (fn (x as Free (_, Type ("fun", _)), _) => x mem params + | _ => false) (fold (snd #> infer) intros []); + val params' = map (fn x => (case AList.lookup op = new_arities x of + SOME fs => + let + val T = HOLogic.dest_setT (fastype_of x); + val Ts = HOLogic.prodT_factors' fs T; + val x' = map_type (K (Ts ---> HOLogic.boolT)) x + in + (x, (x', + (HOLogic.Collect_const T $ + HOLogic.ap_split' fs T HOLogic.boolT x', + list_abs (map (pair "x") Ts, HOLogic.mk_mem + (HOLogic.mk_tuple' fs T (map Bound (length fs downto 0)), + x))))) + end + | NONE => (x, (x, (x, x))))) params; + val (params1, (params2, params3)) = + params' |> map snd |> split_list ||> split_list; + + (* equations for converting sets to predicates *) + val ((cs', cs_info), eqns) = cs |> map (fn c as Free (s, T) => + let + val fs = the_default [] (AList.lookup op = new_arities c); + val U = HOLogic.dest_setT (body_type T); + val Ts = HOLogic.prodT_factors' fs U; + val c' = Free (s ^ "p", + map fastype_of params1 @ Ts ---> HOLogic.boolT) + in + ((c', (fs, U, Ts)), + (list_comb (c, params2), + HOLogic.Collect_const U $ HOLogic.ap_split' fs U HOLogic.boolT + (list_comb (c', params1)))) + end) |> split_list |>> split_list; + val eqns' = eqns @ + map (prop_of #> HOLogic.dest_Trueprop #> HOLogic.dest_eq) + (mem_Collect_eq :: split_conv :: to_pred_simps); + + (* predicate version of the introduction rules *) + val intros' = + map (fn (name_atts, t) => (name_atts, + t |> + map_aterms (fn u => + (case AList.lookup op = params' u of + SOME (_, (u', _)) => u' + | NONE => u)) |> + Pattern.rewrite_term thy [] [to_pred_proc thy eqns'] |> + eta_contract (member op = cs' orf is_pred pred_arities))) intros; + val cnames_syn' = map (fn (s, _) => (s ^ "p", NoSyn)) cnames_syn; + val monos' = map (to_pred [] (Context.Proof ctxt)) monos; + val ({preds, intrs, elims, raw_induct, ...}, ctxt1) = + InductivePackage.add_ind_def verbose "" coind + no_elim no_ind cs' intros' monos' params1 cnames_syn' ctxt; + + (* define inductive sets using previously defined predicates *) + val (defs, ctxt2) = LocalTheory.defs Thm.internalK + (map (fn ((c_syn, (fs, U, _)), p) => (c_syn, (("", []), + fold_rev lambda params (HOLogic.Collect_const U $ + HOLogic.ap_split' fs U HOLogic.boolT (list_comb (p, params3)))))) + (cnames_syn ~~ cs_info ~~ preds)) ctxt1; + + (* prove theorems for converting predicate to set notation *) + val ctxt3 = fold + (fn (((p, c as Free (s, _)), (fs, U, Ts)), (_, (_, def))) => fn ctxt => + let val conv_thm = + Goal.prove ctxt (map (fst o dest_Free) params) [] + (HOLogic.mk_Trueprop (HOLogic.mk_eq + (list_comb (p, params3), + list_abs (map (pair "x") Ts, HOLogic.mk_mem + (HOLogic.mk_tuple' fs U (map Bound (length fs downto 0)), + list_comb (c, params)))))) + (K (REPEAT (rtac ext 1) THEN simp_tac (HOL_basic_ss addsimps + [def, mem_Collect_eq, split_conv]) 1)) + in + ctxt |> note_theorem ((s ^ "p_" ^ s ^ "_eq", + [Attrib.internal (K pred_set_conv_att)]), + [conv_thm]) |> snd + end) (preds ~~ cs ~~ cs_info ~~ defs) ctxt2; + + (* convert theorems to set notation *) + val rec_name = if alt_name = "" then + space_implode "_" (map fst cnames_syn) else alt_name; + val cnames = map (Sign.full_name (ProofContext.theory_of ctxt3) o #1) cnames_syn; (* FIXME *) + val (intr_names, intr_atts) = split_list (map fst intros); + val raw_induct' = to_set [] (Context.Proof ctxt3) raw_induct; + val (intrs', elims', induct, ctxt4) = + InductivePackage.declare_rules rec_name coind no_ind cnames + (map (to_set [] (Context.Proof ctxt3)) intrs) intr_names intr_atts + (map (fn th => (to_set [] (Context.Proof ctxt3) th, + map fst (fst (RuleCases.get th)))) elims) + raw_induct' ctxt3 + in + ({intrs = intrs', elims = elims', induct = induct, + raw_induct = raw_induct', preds = map fst defs}, + ctxt4) + end; + +val add_inductive_i = InductivePackage.gen_add_inductive_i add_ind_set_def; +val add_inductive = InductivePackage.gen_add_inductive add_ind_set_def; + +val mono_add_att = to_pred_att [] #> InductivePackage.mono_add; +val mono_del_att = to_pred_att [] #> InductivePackage.mono_del; + + +(** package setup **) + +(* setup theory *) + +val setup = + Attrib.add_attributes + [("pred_set_conv", Attrib.no_args pred_set_conv_att, + "declare rules for converting between predicate and set notation"), + ("to_set", Attrib.syntax (Attrib.thms >> to_set_att), + "convert rule to set notation"), + ("to_pred", Attrib.syntax (Attrib.thms >> to_pred_att), + "convert rule to predicate notation")] #> + Codegen.add_attribute "ind_set" + (Scan.option (Args.$$$ "target" |-- Args.colon |-- Args.name) >> code_ind_att) #> + Codegen.add_preprocessor codegen_preproc #> + Attrib.add_attributes [("mono_set", Attrib.add_del_args mono_add_att mono_del_att, + "declaration of monotonicity rule for set operators")] #> + Context.theory_map (Simplifier.map_ss (fn ss => + ss addsimprocs [collect_mem_simproc])); + +(* outer syntax *) + +local structure P = OuterParse and K = OuterKeyword in + +val ind_set_decl = InductivePackage.gen_ind_decl add_ind_set_def; + +val inductive_setP = + OuterSyntax.command "inductive_set" "define inductive sets" K.thy_decl (ind_set_decl false); + +val coinductive_setP = + OuterSyntax.command "coinductive_set" "define coinductive sets" K.thy_decl (ind_set_decl true); + +val _ = OuterSyntax.add_parsers [inductive_setP, coinductive_setP]; + +end; + +end;