(* Title: HOL/Tools/Function/fundef.ML
Author: Alexander Krauss, TU Muenchen
A package for general recursive function definitions.
Isar commands.
*)
signature FUNCTION =
sig
include FUNCTION_DATA
val add_function : (binding * typ option * mixfix) list
-> (Attrib.binding * term) list
-> Function_Common.function_config
-> local_theory
-> Proof.state
val add_function_cmd : (binding * string option * mixfix) list
-> (Attrib.binding * string) list
-> Function_Common.function_config
-> local_theory
-> Proof.state
val termination_proof : term option -> local_theory -> Proof.state
val termination_proof_cmd : string option -> local_theory -> Proof.state
val setup : theory -> theory
val get_congs : Proof.context -> thm list
val get_info : Proof.context -> term -> info
end
structure Function : FUNCTION =
struct
open Function_Lib
open Function_Common
val simp_attribs = map (Attrib.internal o K)
[Simplifier.simp_add,
Code.add_default_eqn_attribute,
Nitpick_Simps.add]
val psimp_attribs = map (Attrib.internal o K)
[Simplifier.simp_add,
Nitpick_Psimps.add]
fun mk_defname fixes = fixes |> map (fst o fst) |> space_implode "_"
fun add_simps fnames post sort extra_qualify label mod_binding moreatts simps lthy =
let
val spec = post simps
|> map (apfst (apsnd (fn ats => moreatts @ ats)))
|> map (apfst (apfst extra_qualify))
val (saved_spec_simps, lthy) =
fold_map Local_Theory.note spec lthy
val saved_simps = maps snd saved_spec_simps
val simps_by_f = sort saved_simps
fun add_for_f fname simps =
Local_Theory.note
((mod_binding (Binding.qualify true fname (Binding.name label)), []), simps)
#> snd
in
(saved_simps,
fold2 add_for_f fnames simps_by_f lthy)
end
fun gen_add_function is_external prep default_constraint fixspec eqns config 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) eqns lthy
val fixes = map (apfst (apfst Binding.name_of)) fixes0;
val spec = map (fn (bnd, prop) => (bnd, [prop])) spec0;
val (eqs, post, sort_cont, cnames) = get_preproc lthy config ctxt' fixes spec
val defname = mk_defname fixes
val FunctionConfig {partials, ...} = config
val ((goalstate, cont), lthy) =
Function_Mutual.prepare_function_mutual config defname fixes eqs lthy
fun afterqed [[proof]] lthy =
let
val FunctionResult {fs, R, psimps, trsimps, simple_pinducts, termination,
domintros, cases, ...} =
cont (Thm.close_derivation proof)
val fnames = map (fst o fst) fixes
fun qualify n = Binding.name n
|> Binding.qualify true defname
val conceal_partial = if partials then I else Binding.conceal
val addsmps = add_simps fnames post sort_cont
val (((psimps', pinducts'), (_, [termination'])), lthy) =
lthy
|> addsmps (conceal_partial o Binding.qualify false "partial")
"psimps" conceal_partial psimp_attribs psimps
||> fold_option (snd oo addsmps I "simps" I simp_attribs) trsimps
||>> Local_Theory.note ((conceal_partial (qualify "pinduct"),
[Attrib.internal (K (Rule_Cases.case_names cnames)),
Attrib.internal (K (Rule_Cases.consumes 1)),
Attrib.internal (K (Induct.induct_pred ""))]), simple_pinducts)
||>> Local_Theory.note ((Binding.conceal (qualify "termination"), []), [termination])
||> (snd o Local_Theory.note ((qualify "cases",
[Attrib.internal (K (Rule_Cases.case_names cnames))]), [cases]))
||> fold_option (snd oo curry Local_Theory.note (qualify "domintros", [])) domintros
val info = { add_simps=addsmps, case_names=cnames, psimps=psimps',
pinducts=snd pinducts', termination=termination', fs=fs, R=R,
defname=defname, is_partial=true }
val _ =
if not is_external then ()
else Specification.print_consts lthy (K false) (map fst fixes)
in
lthy
|> Local_Theory.declaration false (add_function_data o morph_function_data info)
end
in
lthy
|> Proof.theorem_i NONE afterqed [[(Logic.unprotect (concl_of goalstate), [])]]
|> Proof.refine (Method.primitive_text (fn _ => goalstate)) |> Seq.hd
end
val add_function = gen_add_function false Specification.check_spec (TypeInfer.anyT HOLogic.typeS)
val add_function_cmd = gen_add_function true Specification.read_spec "_::type"
fun gen_termination_proof prep_term raw_term_opt lthy =
let
val term_opt = Option.map (prep_term lthy) raw_term_opt
val info = the (case term_opt of
SOME t => (import_function_data t lthy
handle Option.Option =>
error ("Not a function: " ^ quote (Syntax.string_of_term lthy t)))
| NONE => (import_last_function lthy handle Option.Option => error "Not a function"))
val { termination, fs, R, add_simps, case_names, psimps,
pinducts, defname, ...} = info
val domT = domain_type (fastype_of R)
val goal = HOLogic.mk_Trueprop
(HOLogic.mk_all ("x", domT, mk_acc domT R $ Free ("x", domT)))
fun afterqed [[totality]] lthy =
let
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 info' = { is_partial=false, defname=defname, add_simps=add_simps,
case_names=case_names, fs=fs, R=R, psimps=psimps, pinducts=pinducts,
termination=termination }
fun qualify n = Binding.name n
|> Binding.qualify true defname
in
lthy
|> add_simps I "simps" I simp_attribs tsimps |> snd
|> Local_Theory.note
((qualify "induct",
[Attrib.internal (K (Rule_Cases.case_names case_names))]),
tinduct) |> snd
|> Local_Theory.declaration false (add_function_data o morph_function_data info')
end
in
lthy
|> ProofContext.note_thmss ""
[((Binding.empty, [Context_Rules.rule_del]), [([allI], [])])] |> snd
|> ProofContext.note_thmss ""
[((Binding.empty, [Context_Rules.intro_bang (SOME 1)]), [([allI], [])])] |> snd
|> ProofContext.note_thmss ""
[((Binding.name "termination", [Context_Rules.intro_bang (SOME 0)]),
[([Goal.norm_result termination], [])])] |> snd
|> Proof.theorem_i NONE afterqed [[(goal, [])]]
end
val termination_proof = gen_termination_proof Syntax.check_term
val termination_proof_cmd = gen_termination_proof Syntax.read_term
(* Datatype hook to declare datatype congs as "function_congs" *)
fun add_case_cong n thy =
Context.theory_map (Function_Ctx_Tree.map_function_congs (Thm.add_thm
(Datatype.the_info thy n
|> #case_cong
|> safe_mk_meta_eq)))
thy
val setup_case_cong = Datatype.interpretation (K (fold add_case_cong))
(* setup *)
val setup =
Attrib.setup @{binding fundef_cong}
(Attrib.add_del Function_Ctx_Tree.cong_add Function_Ctx_Tree.cong_del)
"declaration of congruence rule for function definitions"
#> setup_case_cong
#> Function_Relation.setup
#> Function_Common.Termination_Simps.setup
val get_congs = Function_Ctx_Tree.get_function_congs
fun get_info ctxt t = Item_Net.retrieve (get_function ctxt) t
|> the_single |> snd
(* outer syntax *)
local structure P = OuterParse and K = OuterKeyword in
val _ =
OuterSyntax.local_theory_to_proof "function" "define general recursive functions" K.thy_goal
(function_parser default_config
>> (fn ((config, fixes), statements) => add_function_cmd fixes statements config))
val _ =
OuterSyntax.local_theory_to_proof "termination" "prove termination of a recursive function" K.thy_goal
(Scan.option P.term >> termination_proof_cmd)
end
end