krauss@19564: (*  Title:      HOL/Tools/function_package/fundef_package.ML
krauss@19564:     ID:         $Id$
krauss@19564:     Author:     Alexander Krauss, TU Muenchen
krauss@19564: 
wenzelm@20363: A package for general recursive function definitions.
krauss@19564: Isar commands.
krauss@19564: 
krauss@19564: *)
krauss@19564: 
wenzelm@20363: signature FUNDEF_PACKAGE =
krauss@19564: sig
wenzelm@20877:     val add_fundef :  (string * string option * mixfix) list
krauss@20523:                       -> ((bstring * Attrib.src list) * string list) list list
wenzelm@20877:                       -> FundefCommon.fundef_config
wenzelm@20877:                       -> local_theory
krauss@21211:                       -> string * Proof.state
krauss@20523: 
wenzelm@20877:     val add_fundef_i:  (string * typ option * mixfix) list
krauss@20523:                        -> ((bstring * Attrib.src list) * term list) list list
wenzelm@20877:                        -> bool
wenzelm@20877:                        -> local_theory
krauss@21211:                        -> string * Proof.state
krauss@21211: 
krauss@21211:     val setup_termination_proof : string option -> local_theory -> Proof.state
krauss@19564: 
krauss@19564:     val cong_add: attribute
krauss@19564:     val cong_del: attribute
wenzelm@20363: 
krauss@19564:     val setup : theory -> theory
krauss@21235:     val setup_case_cong_hook : theory -> theory
krauss@19770:     val get_congs : theory -> thm list
krauss@19564: end
krauss@19564: 
krauss@19564: 
krauss@20523: structure FundefPackage  =
krauss@19564: struct
krauss@19564: 
krauss@21051: open FundefLib
krauss@19564: open FundefCommon
krauss@19564: 
krauss@20654: (*fn (ctxt,s) => Variable.importT_terms (fst (ProofContext.read_termTs ctxt (K false) (K NONE) (K NONE) [] [s])) ctxt;*)
krauss@19564: 
krauss@20523: fun burrow_snd f ps = (* ('a list -> 'b list) -> ('c * 'a) list -> ('c * 'b) list *)
krauss@20523:     let val (xs, ys) = split_list ps
krauss@20523:     in xs ~~ f ys end
krauss@20270: 
krauss@20523: fun restore_spec_structure reps spec =
krauss@20523:     (burrow o burrow_snd o burrow o K) reps spec
wenzelm@20363: 
krauss@20523: fun add_simps label moreatts mutual_info fixes psimps spec lthy =
krauss@19564:     let
krauss@20523:       val fnames = map (fst o fst) fixes
krauss@20523:       val psimps_by_f = FundefMutual.sort_by_function mutual_info fnames psimps
krauss@19564: 
krauss@20523:       fun add_for_f fname psimps =
wenzelm@20877:           LocalTheory.note ((NameSpace.append fname label, Attrib.internal Simplifier.simp_add :: moreatts), psimps) #> snd
krauss@19564:     in
krauss@20523:       lthy
krauss@20523:         |> fold_map (fold_map LocalTheory.note) (restore_spec_structure psimps spec) |> snd
krauss@20523:         |> fold2 add_for_f fnames psimps_by_f
krauss@19564:     end
krauss@19564: 
krauss@19564: 
krauss@20523: fun fundef_afterqed fixes spec mutual_info defname data [[result]] lthy =
krauss@20523:     let
krauss@20523:         val fundef_data = FundefMutual.mk_partial_rules_mutual lthy mutual_info data result
krauss@20523:         val FundefMResult {psimps, subset_pinducts, simple_pinducts, termination, domintros, cases, ...} = fundef_data
wenzelm@20877:         val qualify = NameSpace.append defname;
krauss@20523:     in
krauss@20523:       lthy
krauss@20523:         |> add_simps "psimps" [] mutual_info fixes psimps spec
wenzelm@20877:         |> LocalTheory.note ((qualify "domintros", []), domintros) |> snd
wenzelm@20877:         |> LocalTheory.note ((qualify "termination", []), [termination]) |> snd
wenzelm@20877:         |> LocalTheory.note ((qualify "cases", []), [cases]) |> snd
wenzelm@20877:         |> LocalTheory.note ((qualify "pinduct", [Attrib.internal (InductAttrib.induct_set "")]), simple_pinducts) |> snd
wenzelm@20877:         |> LocalTheory.declaration (add_fundef_data defname (fundef_data, mutual_info, (fixes,spec)))
krauss@20523:     end (* FIXME: Add cases for induct and cases thm *)
krauss@20523: 
krauss@20523: 
krauss@20523: 
krauss@20523: fun prep_with_flags prep fixspec eqnss_flags global_flag lthy =
krauss@19564:     let
krauss@20523:       val eqnss = map (map (apsnd (map fst))) eqnss_flags
krauss@20523:       val flags = map (map (map (fn (_, f) => global_flag orelse f) o snd)) eqnss_flags
krauss@20523: 
krauss@20523:       val ((fixes, _), ctxt') = prep fixspec [] lthy
krauss@20523:       val spec = map (fn eqns => snd (fst (prep [] eqns ctxt'))) eqnss
krauss@20523:                      |> map (map (apsnd (map (fn t => fold_rev (mk_forall o Free) (frees_in_term ctxt' t) t)))) (* Add quantifiers *)
krauss@20523:                      |> map2 (map2 (fn fs => fn (r, thms) => (r, fs ~~ thms))) flags
wenzelm@20877:                      |> (burrow o burrow_snd o burrow)
krauss@20523:                           (FundefSplit.split_some_equations lthy)
krauss@20523:                      |> map (map (apsnd flat))
krauss@20523:     in
krauss@20523:       ((fixes, spec), ctxt')
krauss@20523:     end
krauss@20523: 
krauss@19564: 
krauss@20654: fun gen_add_fundef prep_spec fixspec eqnss_flags config lthy =
krauss@20523:     let
krauss@20654:       val FundefConfig {sequential, default, ...} = config
krauss@20654: 
krauss@20654:       val ((fixes, spec), ctxt') = prep_with_flags prep_spec fixspec eqnss_flags sequential lthy
krauss@20523:       val t_eqns = spec
krauss@20523:                      |> flat |> map snd |> flat (* flatten external structure *)
krauss@20523: 
wenzelm@20877:       val ((mutual_info, name, prep_result as Prep {goal, goalI, ...}), lthy) =
krauss@20654:           FundefMutual.prepare_fundef_mutual fixes t_eqns default lthy
krauss@20523: 
krauss@20523:       val afterqed = fundef_afterqed fixes spec mutual_info name prep_result
krauss@20523:     in
krauss@21211:       (name, lthy
krauss@21211:          |> Proof.theorem_i PureThy.internalK NONE afterqed NONE ("", []) [(("", []), [(goal, [])])]
krauss@21211:          |> Proof.refine (Method.primitive_text (fn _ => goalI)) |> Seq.hd)
krauss@20523:     end
krauss@20523: 
krauss@20523: 
krauss@20523: fun total_termination_afterqed defname data [[totality]] lthy =
krauss@20523:     let
krauss@20523:         val (FundefMResult {psimps, simple_pinducts, ... }, mutual_info, (fixes, stmts)) = data
krauss@19564: 
wenzelm@20363:         val remove_domain_condition = full_simplify (HOL_basic_ss addsimps [totality, True_implies_equals])
krauss@19564: 
krauss@20523:         val tsimps = map remove_domain_condition psimps
wenzelm@20363:         val tinduct = map remove_domain_condition simple_pinducts
krauss@19770: 
wenzelm@20877:         (* FIXME: How to generate code from (possibly) local contexts
krauss@20523:         val has_guards = exists ((fn (Const ("Trueprop", _) $ _) => false | _ => true) o prop_of) tsimps
krauss@20523:         val allatts = if has_guards then [] else [Attrib.internal (RecfunCodegen.add NONE)]
krauss@20523:         *)
wenzelm@20877:         val qualify = NameSpace.append defname;
krauss@19564:     in
krauss@20523:         lthy
krauss@20523:           |> add_simps "simps" [] mutual_info fixes tsimps stmts
wenzelm@20877:           |> LocalTheory.note ((qualify "induct", []), tinduct) |> snd
wenzelm@20363:     end
krauss@19564: 
krauss@19564: 
krauss@21211: fun setup_termination_proof name_opt lthy =
krauss@20523:     let
krauss@20523:         val name = the_default (get_last_fundef (Context.Proof lthy)) name_opt
krauss@20523:         val data = the (get_fundef_data name (Context.Proof lthy))
krauss@20523:                    handle Option.Option => raise ERROR ("No such function definition: " ^ name)
krauss@20523: 
krauss@20523:         val (res as FundefMResult {termination, ...}, _, _) = data
krauss@20523:         val goal = FundefTermination.mk_total_termination_goal data
krauss@20523:     in
wenzelm@20877:       lthy
krauss@20523:         |> ProofContext.note_thmss_i [(("termination",
krauss@21237:                                         [ContextRules.intro_query NONE]), [(ProofContext.standard lthy [termination], [])])] |> snd
krauss@20523:         |> Proof.theorem_i PureThy.internalK NONE
krauss@20523:                            (total_termination_afterqed name data) NONE ("", [])
krauss@20523:                            [(("", []), [(goal, [])])]
krauss@20523:     end
krauss@20523: 
krauss@20523: 
krauss@20523: val add_fundef = gen_add_fundef Specification.read_specification
krauss@20523: val add_fundef_i = gen_add_fundef Specification.cert_specification
krauss@19611: 
krauss@19564: 
krauss@19564: 
krauss@19564: (* congruence rules *)
krauss@19564: 
wenzelm@19617: val cong_add = Thm.declaration_attribute (map_fundef_congs o Drule.add_rule o safe_mk_meta_eq);
wenzelm@19617: val cong_del = Thm.declaration_attribute (map_fundef_congs o Drule.del_rule o safe_mk_meta_eq);
krauss@19564: 
krauss@21235: (* Datatype hook to declare datatype congs as "fundef_congs" *)
krauss@21235: 
krauss@21235: 
krauss@21235: fun add_case_cong n thy = 
krauss@21235:     Context.theory_map (map_fundef_congs (Drule.add_rule 
krauss@21235:                           (DatatypePackage.get_datatype thy n |> the
krauss@21235:                            |> #case_cong
krauss@21235:                            |> safe_mk_meta_eq))) 
krauss@21235:                        thy
krauss@21235: 
krauss@21235: val case_cong_hook = fold add_case_cong
krauss@21235: 
krauss@21235: val setup_case_cong_hook = 
krauss@21235:     DatatypeHooks.add case_cong_hook
krauss@21235:     #> (fn thy => case_cong_hook (Symtab.keys (DatatypePackage.get_datatypes thy)) thy)
krauss@19564: 
krauss@19564: (* setup *)
krauss@19564: 
krauss@21235: val setup = 
krauss@21235:     FundefData.init 
krauss@21235:       #> FundefCongs.init
krauss@21235:       #>  Attrib.add_attributes
krauss@21235:             [("fundef_cong", Attrib.add_del_args cong_add cong_del, "declaration of congruence rule for function definitions")]
krauss@21235:       #> setup_case_cong_hook
krauss@19564: 
krauss@19770: val get_congs = FundefCommon.get_fundef_congs o Context.Theory
krauss@19770: 
krauss@19770: 
krauss@21235: 
krauss@19564: (* outer syntax *)
krauss@19564: 
krauss@19564: local structure P = OuterParse and K = OuterKeyword in
krauss@19564: 
krauss@20270: 
krauss@20270: 
krauss@20523: fun or_list1 s = P.enum1 "|" s
krauss@20523: 
krauss@20523: val opt_sequential = Scan.optional ((P.$$$ "(" |-- P.$$$ "sequential" --| P.$$$ ")") >> K true) false
krauss@20523: 
krauss@20523: val otherwise = P.$$$ "(" |-- P.$$$ "otherwise" --| P.$$$ ")"
krauss@20523: val statement_ow = P.and_list1 (P.opt_thm_name ":" -- Scan.repeat1 (P.prop -- Scan.optional (otherwise >> K true) false))
krauss@20523: val statements_ow = or_list1 statement_ow
krauss@20270: 
krauss@20270: 
krauss@19564: val functionP =
krauss@19564:   OuterSyntax.command "function" "define general recursive functions" K.thy_goal
krauss@21051:   ((config_parser default_config -- P.opt_locale_target -- P.fixes --| P.$$$ "where" -- statements_ow)
krauss@20654:      >> (fn (((config, target), fixes), statements) =>
krauss@21211:             Toplevel.local_theory_to_proof target (add_fundef fixes statements config #> snd)
krauss@21211:             #> Toplevel.print));
krauss@20523: 
krauss@19564: 
krauss@21051: 
krauss@19564: val terminationP =
krauss@19564:   OuterSyntax.command "termination" "prove termination of a recursive function" K.thy_goal
wenzelm@21000:   (P.opt_locale_target -- Scan.option P.name
wenzelm@21000:     >> (fn (target, name) =>
wenzelm@21000:            Toplevel.print o
krauss@21211:            Toplevel.local_theory_to_proof target (setup_termination_proof name)));
krauss@19564: 
krauss@20338: 
krauss@19564: val _ = OuterSyntax.add_parsers [functionP];
krauss@19564: val _ = OuterSyntax.add_parsers [terminationP];
krauss@20654: val _ = OuterSyntax.add_keywords ["sequential", "otherwise"];
krauss@19564: 
krauss@19564: end;
krauss@19564: 
krauss@19564: 
wenzelm@19585: end