diff --git a/src/HOL/Tools/Function/function_core.ML b/src/HOL/Tools/Function/function_core.ML --- a/src/HOL/Tools/Function/function_core.ML +++ b/src/HOL/Tools/Function/function_core.ML @@ -1,925 +1,925 @@ (* Title: HOL/Tools/Function/function_core.ML Author: Alexander Krauss, TU Muenchen Core of the function package. *) signature FUNCTION_CORE = sig val trace: bool Unsynchronized.ref val prepare_function : Function_Common.function_config -> binding (* defname *) -> ((binding * typ) * mixfix) list (* defined symbol *) -> ((string * typ) list * term list * term * term) list (* specification *) -> local_theory -> (term (* f *) * thm (* goalstate *) * (Proof.context -> thm -> Function_Common.function_result) (* continuation *) ) * local_theory end structure Function_Core : FUNCTION_CORE = struct val trace = Unsynchronized.ref false fun trace_msg msg = if ! trace then tracing (msg ()) else () val boolT = HOLogic.boolT val mk_eq = HOLogic.mk_eq open Function_Lib open Function_Common datatype globals = Globals of {fvar: term, domT: typ, ranT: typ, h: term, y: term, x: term, z: term, a: term, P: term, D: term, Pbool:term} datatype rec_call_info = RCInfo of {RIvs: (string * typ) list, (* Call context: fixes and assumes *) CCas: thm list, rcarg: term, (* The recursive argument *) llRI: thm, h_assum: term} datatype clause_context = ClauseContext of {ctxt : Proof.context, qs : term list, gs : term list, lhs: term, rhs: term, cqs: cterm list, ags: thm list, case_hyp : thm} fun transfer_clause_ctx thy (ClauseContext { ctxt, qs, gs, lhs, rhs, cqs, ags, case_hyp }) = ClauseContext { ctxt = Proof_Context.transfer thy ctxt, qs = qs, gs = gs, lhs = lhs, rhs = rhs, cqs = cqs, ags = ags, case_hyp = case_hyp } datatype clause_info = ClauseInfo of {no: int, qglr : ((string * typ) list * term list * term * term), cdata : clause_context, tree: Function_Context_Tree.ctx_tree, lGI: thm, RCs: rec_call_info list} (* Theory dependencies. *) val acc_induct_rule = @{thm accp_induct_rule} val ex1_implies_ex = @{thm Fun_Def.fundef_ex1_existence} val ex1_implies_un = @{thm Fun_Def.fundef_ex1_uniqueness} val ex1_implies_iff = @{thm Fun_Def.fundef_ex1_iff} val acc_downward = @{thm accp_downward} val accI = @{thm accp.accI} fun find_calls tree = let fun add_Ri (fixes,assumes) (_ $ arg) _ (_, xs) = ([], (fixes, assumes, arg) :: xs) | add_Ri _ _ _ _ = raise Match in rev (Function_Context_Tree.traverse_tree add_Ri tree []) end (** building proof obligations *) fun mk_compat_proof_obligations domT ranT fvar f glrs = let fun mk_impl ((qs, gs, lhs, rhs),(qs', gs', lhs', rhs')) = let val shift = incr_boundvars (length qs') in Logic.mk_implies (HOLogic.mk_Trueprop (HOLogic.eq_const domT $ shift lhs $ lhs'), HOLogic.mk_Trueprop (HOLogic.eq_const ranT $ shift rhs $ rhs')) |> fold_rev (curry Logic.mk_implies) (map shift gs @ gs') |> fold_rev (fn (n,T) => fn b => Logic.all_const T $ Abs(n,T,b)) (qs @ qs') |> curry abstract_over fvar |> curry subst_bound f end in map mk_impl (unordered_pairs glrs) end fun mk_completeness (Globals {x, Pbool, ...}) clauses qglrs = let fun mk_case (ClauseContext {qs, gs, lhs, ...}, (oqs, _, _, _)) = HOLogic.mk_Trueprop Pbool |> curry Logic.mk_implies (HOLogic.mk_Trueprop (mk_eq (x, lhs))) |> fold_rev (curry Logic.mk_implies) gs |> fold_rev mk_forall_rename (map fst oqs ~~ qs) in HOLogic.mk_Trueprop Pbool |> fold_rev (curry Logic.mk_implies o mk_case) (clauses ~~ qglrs) |> mk_forall_rename ("x", x) |> mk_forall_rename ("P", Pbool) end (** making a context with it's own local bindings **) fun mk_clause_context x ctxt (pre_qs,pre_gs,pre_lhs,pre_rhs) = let val (qs, ctxt') = Variable.variant_fixes (map fst pre_qs) ctxt |>> map2 (fn (_, T) => fn n => Free (n, T)) pre_qs fun inst t = subst_bounds (rev qs, t) val gs = map inst pre_gs val lhs = inst pre_lhs val rhs = inst pre_rhs val cqs = map (Thm.cterm_of ctxt') qs val ags = map (Thm.assume o Thm.cterm_of ctxt') gs val case_hyp = Thm.assume (Thm.cterm_of ctxt' (HOLogic.mk_Trueprop (mk_eq (x, lhs)))) in ClauseContext { ctxt = ctxt', qs = qs, gs = gs, lhs = lhs, rhs = rhs, cqs = cqs, ags = ags, case_hyp = case_hyp } end (* lowlevel term function. FIXME: remove *) fun abstract_over_list vs body = let fun abs lev v tm = if v aconv tm then Bound lev else (case tm of Abs (a, T, t) => Abs (a, T, abs (lev + 1) v t) | t $ u => abs lev v t $ abs lev v u | t => t) in fold_index (fn (i, v) => fn t => abs i v t) vs body end fun mk_clause_info globals G f no cdata qglr tree RCs GIntro_thm RIntro_thms = let val Globals {h, ...} = globals val ClauseContext { ctxt, qs, cqs, ags, ... } = cdata (* Instantiate the GIntro thm with "f" and import into the clause context. *) val lGI = GIntro_thm |> Thm.forall_elim (Thm.cterm_of ctxt f) |> fold Thm.forall_elim cqs |> fold Thm.elim_implies ags fun mk_call_info (rcfix, rcassm, rcarg) RI = let val llRI = RI |> fold Thm.forall_elim cqs |> fold (Thm.forall_elim o Thm.cterm_of ctxt o Free) rcfix |> fold Thm.elim_implies ags |> fold Thm.elim_implies rcassm val h_assum = HOLogic.mk_Trueprop (G $ rcarg $ (h $ rcarg)) |> fold_rev (curry Logic.mk_implies o Thm.prop_of) rcassm |> fold_rev (Logic.all o Free) rcfix |> Pattern.rewrite_term (Proof_Context.theory_of ctxt) [(f, h)] [] |> abstract_over_list (rev qs) in RCInfo {RIvs=rcfix, rcarg=rcarg, CCas=rcassm, llRI=llRI, h_assum=h_assum} end val RC_infos = map2 mk_call_info RCs RIntro_thms in ClauseInfo {no=no, cdata=cdata, qglr=qglr, lGI=lGI, RCs=RC_infos, tree=tree} end fun store_compat_thms 0 thms = [] | store_compat_thms n thms = let val (thms1, thms2) = chop n thms in (thms1 :: store_compat_thms (n - 1) thms2) end (* expects i <= j *) fun lookup_compat_thm i j cts = nth (nth cts (i - 1)) (j - i) (* Returns "Gsi, Gsj, lhs_i = lhs_j |-- rhs_j_f = rhs_i_f" *) (* if j < i, then turn around *) fun get_compat_thm ctxt cts i j ctxi ctxj = let val ClauseContext {cqs=cqsi,ags=agsi,lhs=lhsi,...} = ctxi val ClauseContext {cqs=cqsj,ags=agsj,lhs=lhsj,...} = ctxj val lhsi_eq_lhsj = Thm.cterm_of ctxt (HOLogic.mk_Trueprop (mk_eq (lhsi, lhsj))) in if j < i then let val compat = lookup_compat_thm j i cts in compat (* "!!qj qi. Gsj => Gsi => lhsj = lhsi ==> rhsj = rhsi" *) |> fold Thm.forall_elim (cqsj @ cqsi) (* "Gsj => Gsi => lhsj = lhsi ==> rhsj = rhsi" *) |> fold Thm.elim_implies agsj |> fold Thm.elim_implies agsi |> Thm.elim_implies ((Thm.assume lhsi_eq_lhsj) RS sym) (* "Gsj, Gsi, lhsi = lhsj |-- rhsj = rhsi" *) end else let val compat = lookup_compat_thm i j cts in compat (* "!!qi qj. Gsi => Gsj => lhsi = lhsj ==> rhsi = rhsj" *) |> fold Thm.forall_elim (cqsi @ cqsj) (* "Gsi => Gsj => lhsi = lhsj ==> rhsi = rhsj" *) |> fold Thm.elim_implies agsi |> fold Thm.elim_implies agsj |> Thm.elim_implies (Thm.assume lhsi_eq_lhsj) |> (fn thm => thm RS sym) (* "Gsi, Gsj, lhsi = lhsj |-- rhsj = rhsi" *) end end (* Generates the replacement lemma in fully quantified form. *) fun mk_replacement_lemma ctxt h ih_elim clause = let val ClauseInfo {cdata=ClauseContext {qs, cqs, ags, case_hyp, ...}, RCs, tree, ...} = clause local open Conv in val ih_conv = arg1_conv o arg_conv o arg_conv end val ih_elim_case = Conv.fconv_rule (ih_conv (K (case_hyp RS eq_reflection))) ih_elim val Ris = map (fn RCInfo {llRI, ...} => llRI) RCs val h_assums = map (fn RCInfo {h_assum, ...} => Thm.assume (Thm.cterm_of ctxt (subst_bounds (rev qs, h_assum)))) RCs val (eql, _) = Function_Context_Tree.rewrite_by_tree ctxt h ih_elim_case (Ris ~~ h_assums) tree val replace_lemma = HOLogic.mk_obj_eq eql |> Thm.implies_intr (Thm.cprop_of case_hyp) |> fold_rev (Thm.implies_intr o Thm.cprop_of) h_assums |> fold_rev (Thm.implies_intr o Thm.cprop_of) ags |> fold_rev Thm.forall_intr cqs |> Thm.close_derivation \<^here> in replace_lemma end fun mk_uniqueness_clause ctxt globals compat_store clausei clausej RLj = let val thy = Proof_Context.theory_of ctxt val Globals {h, y, x, fvar, ...} = globals val ClauseInfo {no=i, cdata=cctxi as ClauseContext {ctxt=ctxti, lhs=lhsi, case_hyp, ...}, ...} = clausei val ClauseInfo {no=j, qglr=cdescj, RCs=RCsj, ...} = clausej val cctxj as ClauseContext {ags = agsj', lhs = lhsj', rhs = rhsj', qs = qsj', cqs = cqsj', ...} = mk_clause_context x ctxti cdescj val rhsj'h = Pattern.rewrite_term thy [(fvar,h)] [] rhsj' val compat = get_compat_thm ctxt compat_store i j cctxi cctxj val Ghsj' = map (fn RCInfo {h_assum, ...} => Thm.assume (Thm.cterm_of ctxt (subst_bounds (rev qsj', h_assum)))) RCsj val RLj_import = RLj |> fold Thm.forall_elim cqsj' |> fold Thm.elim_implies agsj' |> fold Thm.elim_implies Ghsj' val y_eq_rhsj'h = Thm.assume (Thm.cterm_of ctxt (HOLogic.mk_Trueprop (mk_eq (y, rhsj'h)))) val lhsi_eq_lhsj' = Thm.assume (Thm.cterm_of ctxt (HOLogic.mk_Trueprop (mk_eq (lhsi, lhsj')))) (* lhs_i = lhs_j' |-- lhs_i = lhs_j' *) in (trans OF [case_hyp, lhsi_eq_lhsj']) (* lhs_i = lhs_j' |-- x = lhs_j' *) |> Thm.implies_elim RLj_import (* Rj1' ... Rjk', lhs_i = lhs_j' |-- rhs_j'_h = rhs_j'_f *) |> (fn it => trans OF [it, compat]) (* lhs_i = lhs_j', Gj', Rj1' ... Rjk' |-- rhs_j'_h = rhs_i_f *) |> (fn it => trans OF [y_eq_rhsj'h, it]) (* lhs_i = lhs_j', Gj', Rj1' ... Rjk', y = rhs_j_h' |-- y = rhs_i_f *) |> fold_rev (Thm.implies_intr o Thm.cprop_of) Ghsj' |> fold_rev (Thm.implies_intr o Thm.cprop_of) agsj' (* lhs_i = lhs_j' , y = rhs_j_h' |-- Gj', Rj1'...Rjk' ==> y = rhs_i_f *) |> Thm.implies_intr (Thm.cprop_of y_eq_rhsj'h) |> Thm.implies_intr (Thm.cprop_of lhsi_eq_lhsj') |> fold_rev Thm.forall_intr (Thm.cterm_of ctxt h :: cqsj') end fun mk_uniqueness_case ctxt globals G f ihyp ih_intro G_cases compat_store clauses rep_lemmas clausei = let val thy = Proof_Context.theory_of ctxt val Globals {x, y, ranT, fvar, ...} = globals val ClauseInfo {cdata = ClauseContext {lhs, rhs, cqs, ags, case_hyp, ...}, lGI, RCs, ...} = clausei val rhsC = Pattern.rewrite_term thy [(fvar, f)] [] rhs val ih_intro_case = full_simplify (put_simpset HOL_basic_ss ctxt addsimps [case_hyp]) ih_intro fun prep_RC (RCInfo {llRI, RIvs, CCas, ...}) = (llRI RS ih_intro_case) |> fold_rev (Thm.implies_intr o Thm.cprop_of) CCas |> fold_rev (Thm.forall_intr o Thm.cterm_of ctxt o Free) RIvs val existence = fold (curry op COMP o prep_RC) RCs lGI val P = Thm.cterm_of ctxt (mk_eq (y, rhsC)) val G_lhs_y = Thm.assume (Thm.cterm_of ctxt (HOLogic.mk_Trueprop (G $ lhs $ y))) val unique_clauses = map2 (mk_uniqueness_clause ctxt globals compat_store clausei) clauses rep_lemmas fun elim_implies_eta A AB = Thm.bicompose (SOME ctxt) {flatten = false, match = true, incremented = false} (false, A, 0) 1 AB |> Seq.list_of |> the_single val uniqueness = G_cases |> Thm.forall_elim (Thm.cterm_of ctxt lhs) |> Thm.forall_elim (Thm.cterm_of ctxt y) |> Thm.forall_elim P |> Thm.elim_implies G_lhs_y |> fold elim_implies_eta unique_clauses |> Thm.implies_intr (Thm.cprop_of G_lhs_y) |> Thm.forall_intr (Thm.cterm_of ctxt y) val P2 = Thm.cterm_of ctxt (lambda y (G $ lhs $ y)) (* P2 y := (lhs, y): G *) val exactly_one = @{thm ex1I} |> Thm.instantiate' [SOME (Thm.ctyp_of ctxt ranT)] [SOME P2, SOME (Thm.cterm_of ctxt rhsC)] |> curry (op COMP) existence |> curry (op COMP) uniqueness |> simplify (put_simpset HOL_basic_ss ctxt addsimps [case_hyp RS sym]) |> Thm.implies_intr (Thm.cprop_of case_hyp) |> fold_rev (Thm.implies_intr o Thm.cprop_of) ags |> fold_rev Thm.forall_intr cqs val function_value = existence |> Thm.implies_intr ihyp |> Thm.implies_intr (Thm.cprop_of case_hyp) |> Thm.forall_intr (Thm.cterm_of ctxt x) |> Thm.forall_elim (Thm.cterm_of ctxt lhs) |> curry (op RS) refl in (exactly_one, function_value) end fun prove_stuff ctxt globals G f R clauses complete compat compat_store G_elim f_def = let val Globals {h, domT, ranT, x, ...} = globals (* Inductive Hypothesis: !!z. (z,x):R ==> EX!y. (z,y):G *) val ihyp = Logic.all_const domT $ Abs ("z", domT, Logic.mk_implies (HOLogic.mk_Trueprop (R $ Bound 0 $ x), HOLogic.mk_Trueprop (Const (\<^const_name>\Ex1\, (ranT --> boolT) --> boolT) $ Abs ("y", ranT, G $ Bound 1 $ Bound 0)))) |> Thm.cterm_of ctxt val ihyp_thm = Thm.assume ihyp |> Thm.forall_elim_vars 0 val ih_intro = ihyp_thm RS (f_def RS ex1_implies_ex) val ih_elim = ihyp_thm RS (f_def RS ex1_implies_un) |> Thm.instantiate' [] [NONE, SOME (Thm.cterm_of ctxt h)] val _ = trace_msg (K "Proving Replacement lemmas...") val repLemmas = map (mk_replacement_lemma ctxt h ih_elim) clauses val _ = trace_msg (K "Proving cases for unique existence...") val (ex1s, values) = split_list (map (mk_uniqueness_case ctxt globals G f ihyp ih_intro G_elim compat_store clauses repLemmas) clauses) val _ = trace_msg (K "Proving: Graph is a function") val graph_is_function = complete |> Thm.forall_elim_vars 0 |> fold (curry op COMP) ex1s |> Thm.implies_intr (ihyp) |> Thm.implies_intr (Thm.cterm_of ctxt (HOLogic.mk_Trueprop (mk_acc domT R $ x))) |> Thm.forall_intr (Thm.cterm_of ctxt x) |> (fn it => Drule.compose (it, 2, acc_induct_rule)) (* "EX! y. (?x,y):G" *) |> (fn it => fold (Thm.forall_intr o Thm.cterm_of ctxt o Var) (Term.add_vars (Thm.prop_of it) []) it) val goalstate = Conjunction.intr graph_is_function complete |> Thm.close_derivation \<^here> |> Goal.protect 0 |> fold_rev (Thm.implies_intr o Thm.cprop_of) compat |> Thm.implies_intr (Thm.cprop_of complete) in (goalstate, values) end (* wrapper -- restores quantifiers in rule specifications *) fun inductive_def (binding as ((R, T), _)) intrs lthy = let val ({intrs = intrs_gen, elims = [elim_gen], preds = [ Rdef ], induct, ...}, lthy) = lthy |> Proof_Context.concealed |> Inductive.add_inductive {quiet_mode = true, verbose = ! trace, alt_name = Binding.empty, coind = false, no_elim = false, no_ind = false, skip_mono = true} [binding] (* relation *) [] (* no parameters *) (map (fn t => (Binding.empty_atts, t)) intrs) (* intro rules *) [] (* no special monos *) ||> Proof_Context.restore_naming lthy fun requantify orig_intro thm = let val (qs, t) = dest_all_all orig_intro val frees = Variable.add_frees lthy t [] |> remove (op =) (Binding.name_of R, T) val vars = Term.add_vars (Thm.prop_of thm) [] val varmap = AList.lookup (op =) (frees ~~ map fst vars) #> the_default ("", 0) in fold_rev (fn Free (n, T) => forall_intr_rename (n, Thm.cterm_of lthy (Var (varmap (n, T), T)))) qs thm end in ((Rdef, map2 requantify intrs intrs_gen, Thm.forall_intr_vars elim_gen, induct), lthy) end fun define_graph (G_binding, G_type) fvar clauses RCss lthy = let val G = Free (Binding.name_of G_binding, G_type) fun mk_GIntro (ClauseContext {qs, gs, lhs, rhs, ...}) RCs = let fun mk_h_assm (rcfix, rcassm, rcarg) = HOLogic.mk_Trueprop (G $ rcarg $ (fvar $ rcarg)) |> fold_rev (curry Logic.mk_implies o Thm.prop_of) rcassm |> fold_rev (Logic.all o Free) rcfix in HOLogic.mk_Trueprop (G $ lhs $ rhs) |> fold_rev (curry Logic.mk_implies o mk_h_assm) RCs |> fold_rev (curry Logic.mk_implies) gs |> fold_rev Logic.all (fvar :: qs) end val G_intros = map2 mk_GIntro clauses RCss in inductive_def ((G_binding, G_type), NoSyn) G_intros lthy end fun define_function defname (fname, mixfix) domT ranT G default lthy = let val f_def_binding = Thm.make_def_binding (Config.get lthy function_internals) (derived_name_suffix defname "_sumC") val f_def = Abs ("x", domT, Const (\<^const_name>\Fun_Def.THE_default\, ranT --> (ranT --> boolT) --> ranT) $ (default $ Bound 0) $ Abs ("y", ranT, G $ Bound 1 $ Bound 0)) |> Syntax.check_term lthy in lthy |> Local_Theory.define ((Binding.map_name (suffix "C") fname, mixfix), ((f_def_binding, []), f_def)) end fun define_recursion_relation (R_binding, R_type) qglrs clauses RCss lthy = let val R = Free (Binding.name_of R_binding, R_type) fun mk_RIntro (ClauseContext {qs, gs, lhs, ...}, (oqs, _, _, _)) (rcfix, rcassm, rcarg) = HOLogic.mk_Trueprop (R $ rcarg $ lhs) |> fold_rev (curry Logic.mk_implies o Thm.prop_of) rcassm |> fold_rev (curry Logic.mk_implies) gs |> fold_rev (Logic.all o Free) rcfix |> fold_rev mk_forall_rename (map fst oqs ~~ qs) (* "!!qs xs. CS ==> G => (r, lhs) : R" *) val R_intross = map2 (map o mk_RIntro) (clauses ~~ qglrs) RCss val ((R, RIntro_thms, R_elim, _), lthy) = inductive_def ((R_binding, R_type), NoSyn) (flat R_intross) lthy in ((R, Library.unflat R_intross RIntro_thms, R_elim), lthy) end fun fix_globals domT ranT fvar ctxt = let val ([h, y, x, z, a, D, P, Pbool], ctxt') = Variable.variant_fixes ["h_fd", "y_fd", "x_fd", "z_fd", "a_fd", "D_fd", "P_fd", "Pb_fd"] ctxt in (Globals {h = Free (h, domT --> ranT), y = Free (y, ranT), x = Free (x, domT), z = Free (z, domT), a = Free (a, domT), D = Free (D, domT --> boolT), P = Free (P, domT --> boolT), Pbool = Free (Pbool, boolT), fvar = fvar, domT = domT, ranT = ranT}, ctxt') end fun inst_RC ctxt fvar f (rcfix, rcassm, rcarg) = let fun inst_term t = subst_bound(f, abstract_over (fvar, t)) in (rcfix, map (Thm.assume o Thm.cterm_of ctxt o inst_term o Thm.prop_of) rcassm, inst_term rcarg) end (********************************************************** * PROVING THE RULES **********************************************************) fun mk_psimps ctxt globals R clauses valthms f_iff graph_is_function = let val Globals {domT, z, ...} = globals fun mk_psimp (ClauseInfo {qglr = (oqs, _, _, _), cdata = ClauseContext {cqs, lhs, ags, ...}, ...}) valthm = let val lhs_acc = Thm.cterm_of ctxt (HOLogic.mk_Trueprop (mk_acc domT R $ lhs)) (* "acc R lhs" *) val z_smaller = Thm.cterm_of ctxt (HOLogic.mk_Trueprop (R $ z $ lhs)) (* "R z lhs" *) in ((Thm.assume z_smaller) RS ((Thm.assume lhs_acc) RS acc_downward)) |> (fn it => it COMP graph_is_function) |> Thm.implies_intr z_smaller |> Thm.forall_intr (Thm.cterm_of ctxt z) |> (fn it => it COMP valthm) |> Thm.implies_intr lhs_acc |> asm_simplify (put_simpset HOL_basic_ss ctxt addsimps [f_iff]) |> fold_rev (Thm.implies_intr o Thm.cprop_of) ags |> fold_rev forall_intr_rename (map fst oqs ~~ cqs) end in map2 mk_psimp clauses valthms end (** Induction rule **) val acc_subset_induct = @{thm predicate1I} RS @{thm accp_subset_induct} fun mk_partial_induct_rule ctxt globals R complete_thm clauses = let val Globals {domT, x, z, a, P, D, ...} = globals val acc_R = mk_acc domT R val x_D = Thm.assume (Thm.cterm_of ctxt (HOLogic.mk_Trueprop (D $ x))) val a_D = Thm.cterm_of ctxt (HOLogic.mk_Trueprop (D $ a)) val D_subset = Thm.cterm_of ctxt (Logic.all x (Logic.mk_implies (HOLogic.mk_Trueprop (D $ x), HOLogic.mk_Trueprop (acc_R $ x)))) val D_dcl = (* "!!x z. [| x: D; (z,x):R |] ==> z:D" *) Logic.all x (Logic.all z (Logic.mk_implies (HOLogic.mk_Trueprop (D $ x), Logic.mk_implies (HOLogic.mk_Trueprop (R $ z $ x), HOLogic.mk_Trueprop (D $ z))))) |> Thm.cterm_of ctxt (* Inductive Hypothesis: !!z. (z,x):R ==> P z *) val ihyp = Logic.all_const domT $ Abs ("z", domT, Logic.mk_implies (HOLogic.mk_Trueprop (R $ Bound 0 $ x), HOLogic.mk_Trueprop (P $ Bound 0))) |> Thm.cterm_of ctxt val aihyp = Thm.assume ihyp fun prove_case clause = let val ClauseInfo {cdata = ClauseContext {ctxt = ctxt1, qs, cqs, ags, gs, lhs, case_hyp, ...}, RCs, qglr = (oqs, _, _, _), ...} = clause val case_hyp_conv = K (case_hyp RS eq_reflection) local open Conv in val lhs_D = fconv_rule (arg_conv (arg_conv (case_hyp_conv))) x_D val sih = - fconv_rule (Conv.binder_conv - (K (arg1_conv (arg_conv (arg_conv case_hyp_conv)))) ctxt1) aihyp + fconv_rule + (binder_conv (K (arg1_conv (arg_conv (arg_conv case_hyp_conv)))) ctxt1) aihyp end fun mk_Prec (RCInfo {llRI, RIvs, CCas, rcarg, ...}) = sih |> Thm.forall_elim (Thm.cterm_of ctxt rcarg) |> Thm.elim_implies llRI |> fold_rev (Thm.implies_intr o Thm.cprop_of) CCas |> fold_rev (Thm.forall_intr o Thm.cterm_of ctxt o Free) RIvs val P_recs = map mk_Prec RCs (* [P rec1, P rec2, ... ] *) val step = HOLogic.mk_Trueprop (P $ lhs) |> fold_rev (curry Logic.mk_implies o Thm.prop_of) P_recs |> fold_rev (curry Logic.mk_implies) gs |> curry Logic.mk_implies (HOLogic.mk_Trueprop (D $ lhs)) |> fold_rev mk_forall_rename (map fst oqs ~~ qs) |> Thm.cterm_of ctxt val P_lhs = Thm.assume step |> fold Thm.forall_elim cqs |> Thm.elim_implies lhs_D |> fold Thm.elim_implies ags |> fold Thm.elim_implies P_recs val res = Thm.cterm_of ctxt (HOLogic.mk_Trueprop (P $ x)) |> Conv.arg_conv (Conv.arg_conv case_hyp_conv) |> Thm.symmetric (* P lhs == P x *) |> (fn eql => Thm.equal_elim eql P_lhs) (* "P x" *) |> Thm.implies_intr (Thm.cprop_of case_hyp) |> fold_rev (Thm.implies_intr o Thm.cprop_of) ags |> fold_rev Thm.forall_intr cqs in (res, step) end val (cases, steps) = split_list (map prove_case clauses) val istep = complete_thm |> Thm.forall_elim_vars 0 |> fold (curry op COMP) cases (* P x *) |> Thm.implies_intr ihyp |> Thm.implies_intr (Thm.cprop_of x_D) |> Thm.forall_intr (Thm.cterm_of ctxt x) val subset_induct_rule = acc_subset_induct |> (curry op COMP) (Thm.assume D_subset) |> (curry op COMP) (Thm.assume D_dcl) |> (curry op COMP) (Thm.assume a_D) |> (curry op COMP) istep |> fold_rev Thm.implies_intr steps |> Thm.implies_intr a_D |> Thm.implies_intr D_dcl |> Thm.implies_intr D_subset val simple_induct_rule = subset_induct_rule |> Thm.forall_intr (Thm.cterm_of ctxt D) |> Thm.forall_elim (Thm.cterm_of ctxt acc_R) |> assume_tac ctxt 1 |> Seq.hd |> (curry op COMP) (acc_downward |> (Thm.instantiate' [SOME (Thm.ctyp_of ctxt domT)] (map (SOME o Thm.cterm_of ctxt) [R, x, z])) |> Thm.forall_intr (Thm.cterm_of ctxt z) |> Thm.forall_intr (Thm.cterm_of ctxt x)) |> Thm.forall_intr (Thm.cterm_of ctxt a) |> Thm.forall_intr (Thm.cterm_of ctxt P) in simple_induct_rule end (* FIXME: broken by design *) fun mk_domain_intro ctxt (Globals {domT, ...}) R R_cases clause = let val ClauseInfo {cdata = ClauseContext {gs, lhs, cqs, ...}, qglr = (oqs, _, _, _), ...} = clause val goal = HOLogic.mk_Trueprop (mk_acc domT R $ lhs) |> fold_rev (curry Logic.mk_implies) gs |> Thm.cterm_of ctxt in Goal.init goal |> (SINGLE (resolve_tac ctxt [accI] 1)) |> the |> (SINGLE (eresolve_tac ctxt [Thm.forall_elim_vars 0 R_cases] 1)) |> the |> (SINGLE (auto_tac ctxt)) |> the |> Goal.conclude |> fold_rev forall_intr_rename (map fst oqs ~~ cqs) end (** Termination rule **) val wf_induct_rule = @{thm Wellfounded.wfP_induct_rule} val wf_in_rel = @{thm Fun_Def.wf_in_rel} val in_rel_def = @{thm Fun_Def.in_rel_def} fun mk_nest_term_case ctxt globals R' ihyp clause = let val Globals {z, ...} = globals val ClauseInfo {cdata = ClauseContext {qs, cqs, ags, lhs, case_hyp, ...}, tree, qglr=(oqs, _, _, _), ...} = clause val ih_case = full_simplify (put_simpset HOL_basic_ss ctxt addsimps [case_hyp]) ihyp fun step (fixes, assumes) (_ $ arg) u (sub,(hyps,thms)) = let val used = (u @ sub) |> map (fn (ctx, thm) => Function_Context_Tree.export_thm ctxt ctx thm) val hyp = HOLogic.mk_Trueprop (R' $ arg $ lhs) |> fold_rev (curry Logic.mk_implies o Thm.prop_of) used (* additional hyps *) |> Function_Context_Tree.export_term (fixes, assumes) |> fold_rev (curry Logic.mk_implies o Thm.prop_of) ags |> fold_rev mk_forall_rename (map fst oqs ~~ qs) |> Thm.cterm_of ctxt val thm = Thm.assume hyp |> fold Thm.forall_elim cqs |> fold Thm.elim_implies ags |> Function_Context_Tree.import_thm ctxt (fixes, assumes) |> fold Thm.elim_implies used (* "(arg, lhs) : R'" *) val z_eq_arg = HOLogic.mk_Trueprop (mk_eq (z, arg)) |> Thm.cterm_of ctxt |> Thm.assume val acc = thm COMP ih_case val z_acc_local = acc |> Conv.fconv_rule (Conv.arg_conv (Conv.arg_conv (K (Thm.symmetric (z_eq_arg RS eq_reflection))))) val ethm = z_acc_local |> Function_Context_Tree.export_thm ctxt (fixes, z_eq_arg :: case_hyp :: ags @ assumes) |> fold_rev forall_intr_rename (map fst oqs ~~ cqs) val sub' = sub @ [(([],[]), acc)] in (sub', (hyp :: hyps, ethm :: thms)) end | step _ _ _ _ = raise Match in Function_Context_Tree.traverse_tree step tree end fun mk_nest_term_rule ctxt globals R R_cases clauses = let val Globals { domT, x, z, ... } = globals val acc_R = mk_acc domT R val ([Rn], ctxt') = Variable.variant_fixes ["R"] ctxt val R' = Free (Rn, fastype_of R) val Rrel = Free (Rn, HOLogic.mk_setT (HOLogic.mk_prodT (domT, domT))) val inrel_R = Const (\<^const_name>\Fun_Def.in_rel\, HOLogic.mk_setT (HOLogic.mk_prodT (domT, domT)) --> fastype_of R) $ Rrel val wfR' = HOLogic.mk_Trueprop (Const (\<^const_name>\Wellfounded.wfP\, (domT --> domT --> boolT) --> boolT) $ R') |> Thm.cterm_of ctxt' (* "wf R'" *) (* Inductive Hypothesis: !!z. (z,x):R' ==> z : acc R *) val ihyp = Logic.all_const domT $ Abs ("z", domT, Logic.mk_implies (HOLogic.mk_Trueprop (R' $ Bound 0 $ x), HOLogic.mk_Trueprop (acc_R $ Bound 0))) |> Thm.cterm_of ctxt' val ihyp_a = Thm.assume ihyp |> Thm.forall_elim_vars 0 val R_z_x = Thm.cterm_of ctxt' (HOLogic.mk_Trueprop (R $ z $ x)) val (hyps, cases) = fold (mk_nest_term_case ctxt' globals R' ihyp_a) clauses ([], []) in R_cases |> Thm.forall_elim (Thm.cterm_of ctxt' z) |> Thm.forall_elim (Thm.cterm_of ctxt' x) |> Thm.forall_elim (Thm.cterm_of ctxt' (acc_R $ z)) |> curry op COMP (Thm.assume R_z_x) |> fold_rev (curry op COMP) cases |> Thm.implies_intr R_z_x |> Thm.forall_intr (Thm.cterm_of ctxt' z) |> (fn it => it COMP accI) |> Thm.implies_intr ihyp |> Thm.forall_intr (Thm.cterm_of ctxt' x) |> (fn it => Drule.compose (it, 2, wf_induct_rule)) |> curry op RS (Thm.assume wfR') |> Thm.forall_intr_vars |> (fn it => it COMP allI) |> fold Thm.implies_intr hyps |> Thm.implies_intr wfR' |> Thm.forall_intr (Thm.cterm_of ctxt' R') |> Thm.forall_elim (Thm.cterm_of ctxt' inrel_R) |> curry op RS wf_in_rel |> full_simplify (put_simpset HOL_basic_ss ctxt' addsimps [in_rel_def]) |> Thm.forall_intr_name ("R", Thm.cterm_of ctxt' Rrel) end fun prepare_function config defname [((fname, fT), mixfix)] abstract_qglrs lthy = let val FunctionConfig {domintros, default=default_opt, ...} = config val default_str = the_default "%x. HOL.undefined" (* FIXME proper term!? *) default_opt val fvar = (Binding.name_of fname, fT) val domT = domain_type fT val ranT = range_type fT val default = Syntax.parse_term lthy default_str |> Type.constraint fT |> Syntax.check_term lthy val (globals, ctxt') = fix_globals domT ranT (Free fvar) lthy val Globals { x, h, ... } = globals val clauses = map (mk_clause_context x ctxt') abstract_qglrs val n = length abstract_qglrs fun build_tree (ClauseContext { ctxt, rhs, ...}) = Function_Context_Tree.mk_tree (Free fvar) h ctxt rhs val trees = map build_tree clauses val RCss = map find_calls trees val ((G, GIntro_thms, G_elim, G_induct), lthy) = PROFILE "def_graph" (define_graph (derived_name_suffix defname "_graph", domT --> ranT --> boolT) (Free fvar) clauses RCss) lthy val ((f, (_, f_defthm)), lthy) = PROFILE "def_fun" (define_function defname (fname, mixfix) domT ranT G default) lthy val RCss = map (map (inst_RC lthy (Free fvar) f)) RCss val trees = map (Function_Context_Tree.inst_tree lthy (Free fvar) f) trees val ((R, RIntro_thmss, R_elim), lthy) = PROFILE "def_rel" (define_recursion_relation (derived_name_suffix defname "_rel", domT --> domT --> boolT) abstract_qglrs clauses RCss) lthy val dom = mk_acc domT R val (_, lthy) = Local_Theory.abbrev Syntax.mode_default ((derived_name_suffix defname "_dom", NoSyn), dom) lthy val newthy = Proof_Context.theory_of lthy val clauses = map (transfer_clause_ctx newthy) clauses val xclauses = PROFILE "xclauses" (@{map 7} (mk_clause_info globals G f) (1 upto n) clauses abstract_qglrs trees RCss GIntro_thms) RIntro_thmss val complete = mk_completeness globals clauses abstract_qglrs |> Thm.cterm_of lthy |> Thm.assume val compat = mk_compat_proof_obligations domT ranT (Free fvar) f abstract_qglrs |> map (Thm.cterm_of lthy #> Thm.assume) val compat_store = store_compat_thms n compat val (goalstate, values) = PROFILE "prove_stuff" (prove_stuff lthy globals G f R xclauses complete compat compat_store G_elim) f_defthm fun mk_partial_rules newctxt provedgoal = let val (graph_is_function, complete_thm) = provedgoal |> Conjunction.elim |> apfst (Thm.forall_elim_vars 0) val f_iff = graph_is_function RS (f_defthm RS ex1_implies_iff) val psimps = PROFILE "Proving simplification rules" (mk_psimps newctxt globals R xclauses values f_iff) graph_is_function val simple_pinduct = PROFILE "Proving partial induction rule" (mk_partial_induct_rule newctxt globals R complete_thm) xclauses val total_intro = PROFILE "Proving nested termination rule" (mk_nest_term_rule newctxt globals R R_elim) xclauses val dom_intros = if domintros then SOME (PROFILE "Proving domain introduction rules" (map (mk_domain_intro lthy globals R R_elim)) xclauses) else NONE in FunctionResult {fs=[f], G=G, R=R, dom=dom, cases=[complete_thm], psimps=psimps, pelims=[], simple_pinducts=[simple_pinduct], termination=total_intro, domintros=dom_intros} end in ((f, goalstate, mk_partial_rules), lthy) end end