(* Title: HOL/Tools/function_package/fundef_package.ML
ID: $Id$
Author: Alexander Krauss, TU Muenchen
A package for general recursive function definitions.
Isar commands.
*)
signature FUNDEF_PACKAGE =
sig
val add_fundef : (binding * string option * mixfix) list
-> (Attrib.binding * string) list
-> FundefCommon.fundef_config
-> bool list
-> local_theory
-> Proof.state
val add_fundef_i: (binding * typ option * mixfix) list
-> (Attrib.binding * term) list
-> FundefCommon.fundef_config
-> bool list
-> local_theory
-> Proof.state
val setup_termination_proof : string option -> local_theory -> Proof.state
val setup : theory -> theory
val get_congs : theory -> thm list
end
structure FundefPackage : FUNDEF_PACKAGE =
struct
open FundefLib
open FundefCommon
fun note_theorem ((name, atts), ths) = LocalTheory.note Thm.theoremK ((Binding.name name, atts), ths)
fun mk_defname fixes = fixes |> map (fst o fst) |> space_implode "_"
fun add_simps fnames post sort extra_qualify label moreatts simps lthy =
let
val atts = Attrib.internal (K Simplifier.simp_add) :: moreatts
val spec = post simps
|> map (apfst (apsnd (append atts)))
|> map (apfst (apfst extra_qualify))
val (saved_spec_simps, lthy) =
fold_map note_theorem spec lthy
val saved_simps = flat (map snd saved_spec_simps)
val simps_by_f = sort saved_simps
fun add_for_f fname simps =
note_theorem ((NameSpace.qualified fname label, []), simps) #> snd
in
(saved_simps,
fold2 add_for_f fnames simps_by_f lthy)
end
fun fundef_afterqed do_print fixes post defname cont sort_cont cnames [[proof]] lthy =
let
val FundefResult {fs, R, psimps, trsimps, simple_pinducts, termination, domintros, cases, ...} =
cont (Thm.close_derivation proof)
val fnames = map (fst o fst) fixes
val qualify = NameSpace.qualified defname
val addsmps = add_simps fnames post sort_cont
val (((psimps', pinducts'), (_, [termination'])), lthy) =
lthy
|> addsmps (NameSpace.qualified "partial") "psimps" [] psimps
||> fold_option (snd oo addsmps I "simps" []) trsimps
||>> note_theorem ((qualify "pinduct",
[Attrib.internal (K (RuleCases.case_names cnames)),
Attrib.internal (K (RuleCases.consumes 1)),
Attrib.internal (K (Induct.induct_pred ""))]), simple_pinducts)
||>> note_theorem ((qualify "termination", []), [termination])
||> (snd o note_theorem ((qualify "cases",
[Attrib.internal (K (RuleCases.case_names cnames))]), [cases]))
||> fold_option (snd oo curry note_theorem (qualify "domintros", [])) domintros
val cdata = FundefCtxData { add_simps=addsmps, case_names=cnames, psimps=psimps',
pinducts=snd pinducts', termination=termination', fs=fs, R=R, defname=defname }
val _ =
if not do_print then ()
else Specification.print_consts lthy (K false) (map fst fixes)
in
lthy
|> LocalTheory.declaration (add_fundef_data o morph_fundef_data cdata)
end
fun gen_add_fundef is_external prep default_constraint fixspec eqnss config flags lthy =
let
val constrn_fxs = map (fn (b, T, mx) => (b, SOME (the_default default_constraint T), mx))
val ((fixes0, spec0), ctxt') =
prep (constrn_fxs fixspec) (map (single o apsnd single) eqnss) lthy
val fixes = map (apfst (apfst Binding.base_name)) fixes0;
val spec = map (apfst (apfst Binding.base_name)) spec0;
val (eqs, post, sort_cont, cnames) = FundefCommon.get_preproc lthy config flags ctxt' fixes spec
val defname = mk_defname fixes
val ((goalstate, cont), lthy) =
FundefMutual.prepare_fundef_mutual config defname fixes eqs lthy
val afterqed = fundef_afterqed is_external fixes post defname cont sort_cont cnames
in
lthy
|> is_external ? LocalTheory.set_group (serial_string ())
|> Proof.theorem_i NONE afterqed [[(Logic.unprotect (concl_of goalstate), [])]]
|> Proof.refine (Method.primitive_text (fn _ => goalstate)) |> Seq.hd
end
fun total_termination_afterqed data [[totality]] lthy =
let
val FundefCtxData { add_simps, case_names, psimps, pinducts, defname, ... } = data
val totality = Thm.close_derivation totality
val remove_domain_condition = full_simplify (HOL_basic_ss addsimps [totality, True_implies_equals])
val tsimps = map remove_domain_condition psimps
val tinduct = map remove_domain_condition pinducts
val has_guards = exists ((fn (Const ("Trueprop", _) $ _) => false | _ => true) o prop_of) tsimps
val allatts = if has_guards then [] else [Code.add_default_eqn_attrib]
val qualify = NameSpace.qualified defname;
in
lthy
|> add_simps I "simps" allatts tsimps |> snd
|> note_theorem ((qualify "induct", [Attrib.internal (K (RuleCases.case_names case_names))]), tinduct) |> snd
end
fun setup_termination_proof term_opt lthy =
let
val data = the (case term_opt of
SOME t => import_fundef_data (Syntax.read_term lthy t) (Context.Proof lthy)
| NONE => import_last_fundef (Context.Proof lthy))
handle Option.Option => error ("Not a function: " ^ quote (the_default "" term_opt))
val FundefCtxData {termination, R, ...} = data
val domT = domain_type (fastype_of R)
val goal = HOLogic.mk_Trueprop (HOLogic.mk_all ("x", domT, mk_acc domT R $ Free ("x", domT)))
in
lthy
|> ProofContext.note_thmss_i "" [((Binding.empty, [ContextRules.rule_del]), [([allI], [])])] |> snd
|> ProofContext.note_thmss_i "" [((Binding.empty, [ContextRules.intro_bang (SOME 1)]), [([allI], [])])] |> snd
|> ProofContext.note_thmss_i ""
[((Binding.name "termination", [ContextRules.intro_bang (SOME 0)]),
[([Goal.norm_result termination], [])])] |> snd
|> Proof.theorem_i NONE (total_termination_afterqed data) [[(goal, [])]]
end
fun termination_cmd term_opt lthy =
lthy
|> LocalTheory.set_group (serial_string ())
|> setup_termination_proof term_opt;
val add_fundef = gen_add_fundef true Specification.read_specification "_::type"
val add_fundef_i =
gen_add_fundef false Specification.check_specification (TypeInfer.anyT HOLogic.typeS)
(* Datatype hook to declare datatype congs as "fundef_congs" *)
fun add_case_cong n thy =
Context.theory_map (FundefCtxTree.map_fundef_congs (Thm.add_thm
(DatatypePackage.get_datatype thy n |> the
|> #case_cong
|> safe_mk_meta_eq)))
thy
val case_cong = fold add_case_cong
val setup_case_cong = DatatypePackage.interpretation case_cong
(* setup *)
val setup =
Attrib.add_attributes
[("fundef_cong", Attrib.add_del_args FundefCtxTree.cong_add FundefCtxTree.cong_del,
"declaration of congruence rule for function definitions")]
#> setup_case_cong
#> FundefRelation.setup
#> FundefCommon.TerminationSimps.setup
val get_congs = FundefCtxTree.get_fundef_congs o Context.Theory
(* outer syntax *)
local structure P = OuterParse and K = OuterKeyword in
val _ = OuterKeyword.keyword "otherwise";
val _ =
OuterSyntax.local_theory_to_proof "function" "define general recursive functions" K.thy_goal
(fundef_parser default_config
>> (fn ((config, fixes), (flags, statements)) => add_fundef fixes statements config flags));
val _ =
OuterSyntax.local_theory_to_proof "termination" "prove termination of a recursive function" K.thy_goal
(Scan.option P.term >> termination_cmd);
end;
end