(* Title: Pure/Proof/extraction.ML
Author: Stefan Berghofer, TU Muenchen
Extraction of programs from proofs.
*)
signature EXTRACTION =
sig
val set_preprocessor : (theory -> Proofterm.proof -> Proofterm.proof) -> theory -> theory
val add_realizes_eqns_i : ((term * term) list * (term * term)) list -> theory -> theory
val add_realizes_eqns : string list -> theory -> theory
val add_typeof_eqns_i : ((term * term) list * (term * term)) list -> theory -> theory
val add_typeof_eqns : string list -> theory -> theory
val add_realizers_i : (string * (string list * term * Proofterm.proof)) list
-> theory -> theory
val add_realizers : (thm * (string list * string * string)) list
-> theory -> theory
val add_expand_thm : bool -> thm -> theory -> theory
val add_types : (xstring * ((term -> term option) list *
(term -> typ -> term -> typ -> term) option)) list -> theory -> theory
val extract : (thm * string list) list -> theory -> theory
val nullT : typ
val nullt : term
val mk_typ : typ -> term
val etype_of : theory -> string list -> typ list -> term -> typ
val realizes_of: theory -> string list -> term -> term -> term
val abs_corr_shyps: theory -> thm -> string list -> term list -> Proofterm.proof -> Proofterm.proof
end;
structure Extraction : EXTRACTION =
struct
(**** tools ****)
val typ = Simple_Syntax.read_typ;
val add_syntax =
Sign.root_path
#> Sign.add_types_global
[(Binding.make ("Type", @{here}), 0, NoSyn),
(Binding.make ("Null", @{here}), 0, NoSyn)]
#> Sign.add_consts
[(Binding.make ("typeof", @{here}), typ "'b => Type", NoSyn),
(Binding.make ("Type", @{here}), typ "'a itself => Type", NoSyn),
(Binding.make ("Null", @{here}), typ "Null", NoSyn),
(Binding.make ("realizes", @{here}), typ "'a => 'b => 'b", NoSyn)];
val nullT = Type ("Null", []);
val nullt = Const ("Null", nullT);
fun mk_typ T =
Const ("Type", Term.itselfT T --> Type ("Type", [])) $ Logic.mk_type T;
fun typeof_proc defaultS vs (Const ("typeof", _) $ u) =
SOME (mk_typ (case strip_comb u of
(Var ((a, i), _), _) =>
if member (op =) vs a then TFree ("'" ^ a ^ ":" ^ string_of_int i, defaultS)
else nullT
| (Free (a, _), _) =>
if member (op =) vs a then TFree ("'" ^ a, defaultS) else nullT
| _ => nullT))
| typeof_proc _ _ _ = NONE;
fun rlz_proc (Const ("realizes", Type (_, [Type ("Null", []), _])) $ _ $ t) = SOME t
| rlz_proc (Const ("realizes", Type (_, [T, _])) $ r $ t) =
(case strip_comb t of
(Var (ixn, U), ts) => SOME (list_comb (Var (ixn, T --> U), r :: ts))
| (Free (s, U), ts) => SOME (list_comb (Free (s, T --> U), r :: ts))
| _ => NONE)
| rlz_proc _ = NONE;
val unpack_ixn = apfst implode o apsnd (fst o read_int o tl) o
take_prefix (fn s => s <> ":") o raw_explode;
type rules =
{next: int, rs: ((term * term) list * (term * term)) list,
net: (int * ((term * term) list * (term * term))) Net.net};
val empty_rules : rules = {next = 0, rs = [], net = Net.empty};
fun add_rule (r as (_, (lhs, _))) ({next, rs, net} : rules) =
{next = next - 1, rs = r :: rs, net = Net.insert_term (K false)
(Envir.eta_contract lhs, (next, r)) net};
fun merge_rules ({next, rs = rs1, net} : rules) ({rs = rs2, ...} : rules) =
fold_rev add_rule (subtract (op =) rs1 rs2) {next = next, rs = rs1, net = net};
fun condrew thy rules procs =
let
fun rew tm =
Pattern.rewrite_term thy [] (condrew' :: procs) tm
and condrew' tm =
let
val cache = Unsynchronized.ref ([] : (term * term) list);
fun lookup f x = (case AList.lookup (op =) (!cache) x of
NONE =>
let val y = f x
in (cache := (x, y) :: !cache; y) end
| SOME y => y);
in
get_first (fn (_, (prems, (tm1, tm2))) =>
let
fun ren t = the_default t (Term.rename_abs tm1 tm t);
val inc = Logic.incr_indexes ([], maxidx_of_term tm + 1);
val env as (Tenv, tenv) = Pattern.match thy (inc tm1, tm) (Vartab.empty, Vartab.empty);
val prems' = map (apply2 (Envir.subst_term env o inc o ren)) prems;
val env' = Envir.Envir
{maxidx = fold (fn (t, u) => Term.maxidx_term t #> Term.maxidx_term u) prems' ~1,
tenv = tenv, tyenv = Tenv};
val env'' = fold (Pattern.unify (Context.Theory thy) o apply2 (lookup rew)) prems' env';
in SOME (Envir.norm_term env'' (inc (ren tm2)))
end handle Pattern.MATCH => NONE | Pattern.Unif => NONE)
(sort (int_ord o apply2 fst)
(Net.match_term rules (Envir.eta_contract tm)))
end;
in rew end;
val chtype = Proofterm.change_type o SOME;
fun extr_name s vs = Long_Name.append "extr" (space_implode "_" (s :: vs));
fun corr_name s vs = extr_name s vs ^ "_correctness";
fun msg d s = writeln (Pretty.spaces d ^ s);
fun vars_of t = map Var (rev (Term.add_vars t []));
fun frees_of t = map Free (rev (Term.add_frees t []));
fun vfs_of t = vars_of t @ frees_of t;
val mkabs = fold_rev (fn v => fn t => Abs ("x", fastype_of v, abstract_over (v, t)));
val mkabsp = fold_rev (fn t => fn prf => AbsP ("H", SOME t, prf));
fun strip_abs 0 t = t
| strip_abs n (Abs (_, _, t)) = strip_abs (n-1) t
| strip_abs _ _ = error "strip_abs: not an abstraction";
val prf_subst_TVars = Proofterm.map_proof_types o typ_subst_TVars;
fun relevant_vars types prop =
List.foldr
(fn (Var ((a, _), T), vs) =>
(case body_type T of
Type (s, _) => if member (op =) types s then a :: vs else vs
| _ => vs)
| (_, vs) => vs) [] (vars_of prop);
fun tname_of (Type (s, _)) = s
| tname_of _ = "";
fun get_var_type t =
let
val vs = Term.add_vars t [];
val fs = Term.add_frees t [];
in
fn Var (ixn, _) =>
(case AList.lookup (op =) vs ixn of
NONE => error "get_var_type: no such variable in term"
| SOME T => Var (ixn, T))
| Free (s, _) =>
(case AList.lookup (op =) fs s of
NONE => error "get_var_type: no such variable in term"
| SOME T => Free (s, T))
| _ => error "get_var_type: not a variable"
end;
fun read_term thy T s =
let
val ctxt = Proof_Context.init_global thy
|> Config.put Type_Infer_Context.const_sorts false
|> Proof_Context.set_defsort [];
val parse = if T = propT then Syntax.parse_prop else Syntax.parse_term;
in parse ctxt s |> Type.constraint T |> Syntax.check_term ctxt end;
(**** theory data ****)
(* theory data *)
structure ExtractionData = Theory_Data
(
type T =
{realizes_eqns : rules,
typeof_eqns : rules,
types : (string * ((term -> term option) list *
(term -> typ -> term -> typ -> term) option)) list,
realizers : (string list * (term * proof)) list Symtab.table,
defs : thm list,
expand : string list,
prep : (theory -> proof -> proof) option}
val empty =
{realizes_eqns = empty_rules,
typeof_eqns = empty_rules,
types = [],
realizers = Symtab.empty,
defs = [],
expand = [],
prep = NONE};
val extend = I;
fun merge
({realizes_eqns = realizes_eqns1, typeof_eqns = typeof_eqns1, types = types1,
realizers = realizers1, defs = defs1, expand = expand1, prep = prep1},
{realizes_eqns = realizes_eqns2, typeof_eqns = typeof_eqns2, types = types2,
realizers = realizers2, defs = defs2, expand = expand2, prep = prep2}) : T =
{realizes_eqns = merge_rules realizes_eqns1 realizes_eqns2,
typeof_eqns = merge_rules typeof_eqns1 typeof_eqns2,
types = AList.merge (op =) (K true) (types1, types2),
realizers = Symtab.merge_list (eq_set (op =) o apply2 #1) (realizers1, realizers2),
defs = Library.merge Thm.eq_thm (defs1, defs2),
expand = Library.merge (op =) (expand1, expand2),
prep = if is_some prep1 then prep1 else prep2};
);
fun read_condeq thy =
let val thy' = add_syntax thy
in fn s =>
let val t = Logic.varify_global (read_term thy' propT s)
in
(map Logic.dest_equals (Logic.strip_imp_prems t),
Logic.dest_equals (Logic.strip_imp_concl t))
handle TERM _ => error ("Not a (conditional) meta equality:\n" ^ s)
end
end;
(** preprocessor **)
fun set_preprocessor prep thy =
let val {realizes_eqns, typeof_eqns, types, realizers,
defs, expand, ...} = ExtractionData.get thy
in
ExtractionData.put
{realizes_eqns = realizes_eqns, typeof_eqns = typeof_eqns, types = types,
realizers = realizers, defs = defs, expand = expand, prep = SOME prep} thy
end;
(** equations characterizing realizability **)
fun gen_add_realizes_eqns prep_eq eqns thy =
let val {realizes_eqns, typeof_eqns, types, realizers,
defs, expand, prep} = ExtractionData.get thy;
in
ExtractionData.put
{realizes_eqns = fold_rev add_rule (map (prep_eq thy) eqns) realizes_eqns,
typeof_eqns = typeof_eqns, types = types, realizers = realizers,
defs = defs, expand = expand, prep = prep} thy
end
val add_realizes_eqns_i = gen_add_realizes_eqns (K I);
val add_realizes_eqns = gen_add_realizes_eqns read_condeq;
(** equations characterizing type of extracted program **)
fun gen_add_typeof_eqns prep_eq eqns thy =
let
val {realizes_eqns, typeof_eqns, types, realizers,
defs, expand, prep} = ExtractionData.get thy;
val eqns' = map (prep_eq thy) eqns
in
ExtractionData.put
{realizes_eqns = realizes_eqns, realizers = realizers,
typeof_eqns = fold_rev add_rule eqns' typeof_eqns,
types = types, defs = defs, expand = expand, prep = prep} thy
end
val add_typeof_eqns_i = gen_add_typeof_eqns (K I);
val add_typeof_eqns = gen_add_typeof_eqns read_condeq;
fun thaw (T as TFree (a, S)) =
if exists_string (fn s => s = ":") a then TVar (unpack_ixn a, S) else T
| thaw (Type (a, Ts)) = Type (a, map thaw Ts)
| thaw T = T;
fun freeze (TVar ((a, i), S)) = TFree (a ^ ":" ^ string_of_int i, S)
| freeze (Type (a, Ts)) = Type (a, map freeze Ts)
| freeze T = T;
fun freeze_thaw f x =
map_types thaw (f (map_types freeze x));
fun etype_of thy vs Ts t =
let
val {typeof_eqns, ...} = ExtractionData.get thy;
fun err () = error ("Unable to determine type of extracted program for\n" ^
Syntax.string_of_term_global thy t)
in
(case
strip_abs_body
(freeze_thaw (condrew thy (#net typeof_eqns) [typeof_proc [] vs])
(fold (Term.abs o pair "x") Ts
(Const ("typeof", fastype_of1 (Ts, t) --> Type ("Type", [])) $ t))) of
Const ("Type", _) $ u => (Logic.dest_type u handle TERM _ => err ())
| _ => err ())
end;
(** realizers for axioms / theorems, together with correctness proofs **)
fun gen_add_realizers prep_rlz rs thy =
let val {realizes_eqns, typeof_eqns, types, realizers,
defs, expand, prep} = ExtractionData.get thy
in
ExtractionData.put
{realizes_eqns = realizes_eqns, typeof_eqns = typeof_eqns, types = types,
realizers = fold (Symtab.cons_list o prep_rlz thy) rs realizers,
defs = defs, expand = expand, prep = prep} thy
end
fun prep_realizer thy =
let
val {realizes_eqns, typeof_eqns, defs, types, ...} =
ExtractionData.get thy;
val procs = maps (fst o snd) types;
val rtypes = map fst types;
val eqns = Net.merge (K false) (#net realizes_eqns, #net typeof_eqns);
val thy' = add_syntax thy;
val rd = Proof_Syntax.read_proof thy' true false;
in fn (thm, (vs, s1, s2)) =>
let
val name = Thm.derivation_name thm;
val _ = name <> "" orelse error "add_realizers: unnamed theorem";
val prop = Thm.unconstrainT thm |> Thm.prop_of |>
Pattern.rewrite_term thy' (map (Logic.dest_equals o Thm.prop_of) defs) [];
val vars = vars_of prop;
val vars' = filter_out (fn v =>
member (op =) rtypes (tname_of (body_type (fastype_of v)))) vars;
val shyps = maps (fn Var ((x, i), _) =>
if member (op =) vs x then Logic.mk_of_sort
(TVar (("'" ^ x, i), []), Sign.defaultS thy')
else []) vars;
val T = etype_of thy' vs [] prop;
val (T', thw) = Type.legacy_freeze_thaw_type
(if T = nullT then nullT else map fastype_of vars' ---> T);
val t = map_types thw (read_term thy' T' s1);
val r' = freeze_thaw (condrew thy' eqns
(procs @ [typeof_proc [] vs, rlz_proc]))
(Const ("realizes", T --> propT --> propT) $
(if T = nullT then t else list_comb (t, vars')) $ prop);
val r = Logic.list_implies (shyps,
fold_rev Logic.all (map (get_var_type r') vars) r');
val prf = Reconstruct.reconstruct_proof thy' r (rd s2);
in (name, (vs, (t, prf))) end
end;
val add_realizers_i = gen_add_realizers
(fn _ => fn (name, (vs, t, prf)) => (name, (vs, (t, prf))));
val add_realizers = gen_add_realizers prep_realizer;
fun realizes_of thy vs t prop =
let
val thy' = add_syntax thy;
val {realizes_eqns, typeof_eqns, defs, types, ...} =
ExtractionData.get thy';
val procs = maps (rev o fst o snd) types;
val eqns = Net.merge (K false) (#net realizes_eqns, #net typeof_eqns);
val prop' = Pattern.rewrite_term thy'
(map (Logic.dest_equals o Thm.prop_of) defs) [] prop;
in freeze_thaw (condrew thy' eqns
(procs @ [typeof_proc [] vs, rlz_proc]))
(Const ("realizes", fastype_of t --> propT --> propT) $ t $ prop')
end;
fun abs_corr_shyps thy thm vs xs prf =
let
val S = Sign.defaultS thy;
val ((atyp_map, constraints, _), prop') =
Logic.unconstrainT (#shyps (Thm.rep_thm thm)) (Thm.prop_of thm);
val atyps = fold_types (fold_atyps (insert (op =))) (Thm.prop_of thm) [];
val Ts = map_filter (fn ((v, i), _) => if member (op =) vs v then
SOME (TVar (("'" ^ v, i), [])) else NONE)
(rev (Term.add_vars prop' []));
val cs = maps (fn T => map (pair T) S) Ts;
val constraints' = map Logic.mk_of_class cs;
fun typ_map T = Type.strip_sorts
(map_atyps (fn U => if member (op =) atyps U then atyp_map U else U) T);
fun mk_hyp (T, c) = Hyp (Logic.mk_of_class (typ_map T, c));
val xs' = map (map_types typ_map) xs
in
prf |>
Same.commit (Proofterm.map_proof_same (map_types typ_map) typ_map mk_hyp) |>
fold_rev Proofterm.implies_intr_proof' (map snd constraints) |>
fold_rev Proofterm.forall_intr_proof' xs' |>
fold_rev Proofterm.implies_intr_proof' constraints'
end;
(** expanding theorems / definitions **)
fun add_expand_thm is_def thm thy =
let
val {realizes_eqns, typeof_eqns, types, realizers,
defs, expand, prep} = ExtractionData.get thy;
val name = Thm.derivation_name thm;
val _ = name <> "" orelse error "add_expand_thm: unnamed theorem";
in
thy |> ExtractionData.put
(if is_def then
{realizes_eqns = realizes_eqns,
typeof_eqns = add_rule ([], Logic.dest_equals (map_types
Type.strip_sorts (Thm.prop_of (Drule.abs_def thm)))) typeof_eqns,
types = types,
realizers = realizers, defs = insert Thm.eq_thm thm defs,
expand = expand, prep = prep}
else
{realizes_eqns = realizes_eqns, typeof_eqns = typeof_eqns, types = types,
realizers = realizers, defs = defs,
expand = insert (op =) name expand, prep = prep})
end;
fun extraction_expand is_def =
Thm.declaration_attribute (fn th => Context.mapping (add_expand_thm is_def th) I);
(** types with computational content **)
fun add_types tys thy =
ExtractionData.map
(fn {realizes_eqns, typeof_eqns, types, realizers, defs, expand, prep} =>
{realizes_eqns = realizes_eqns, typeof_eqns = typeof_eqns,
types = fold (AList.update (op =) o apfst (Sign.intern_type thy)) tys types,
realizers = realizers, defs = defs, expand = expand, prep = prep})
thy;
(** Pure setup **)
val _ = Theory.setup
(add_types [("prop", ([], NONE))] #>
add_typeof_eqns
["(typeof (PROP P)) == (Type (TYPE(Null))) ==> \
\ (typeof (PROP Q)) == (Type (TYPE('Q))) ==> \
\ (typeof (PROP P ==> PROP Q)) == (Type (TYPE('Q)))",
"(typeof (PROP Q)) == (Type (TYPE(Null))) ==> \
\ (typeof (PROP P ==> PROP Q)) == (Type (TYPE(Null)))",
"(typeof (PROP P)) == (Type (TYPE('P))) ==> \
\ (typeof (PROP Q)) == (Type (TYPE('Q))) ==> \
\ (typeof (PROP P ==> PROP Q)) == (Type (TYPE('P => 'Q)))",
"(%x. typeof (PROP P (x))) == (%x. Type (TYPE(Null))) ==> \
\ (typeof (!!x. PROP P (x))) == (Type (TYPE(Null)))",
"(%x. typeof (PROP P (x))) == (%x. Type (TYPE('P))) ==> \
\ (typeof (!!x::'a. PROP P (x))) == (Type (TYPE('a => 'P)))",
"(%x. typeof (f (x))) == (%x. Type (TYPE('f))) ==> \
\ (typeof (f)) == (Type (TYPE('f)))"] #>
add_realizes_eqns
["(typeof (PROP P)) == (Type (TYPE(Null))) ==> \
\ (realizes (r) (PROP P ==> PROP Q)) == \
\ (PROP realizes (Null) (PROP P) ==> PROP realizes (r) (PROP Q))",
"(typeof (PROP P)) == (Type (TYPE('P))) ==> \
\ (typeof (PROP Q)) == (Type (TYPE(Null))) ==> \
\ (realizes (r) (PROP P ==> PROP Q)) == \
\ (!!x::'P. PROP realizes (x) (PROP P) ==> PROP realizes (Null) (PROP Q))",
"(realizes (r) (PROP P ==> PROP Q)) == \
\ (!!x. PROP realizes (x) (PROP P) ==> PROP realizes (r (x)) (PROP Q))",
"(%x. typeof (PROP P (x))) == (%x. Type (TYPE(Null))) ==> \
\ (realizes (r) (!!x. PROP P (x))) == \
\ (!!x. PROP realizes (Null) (PROP P (x)))",
"(realizes (r) (!!x. PROP P (x))) == \
\ (!!x. PROP realizes (r (x)) (PROP P (x)))"] #>
Attrib.setup @{binding extraction_expand} (Scan.succeed (extraction_expand false))
"specify theorems to be expanded during extraction" #>
Attrib.setup @{binding extraction_expand_def} (Scan.succeed (extraction_expand true))
"specify definitions to be expanded during extraction");
(**** extract program ****)
val dummyt = Const ("dummy", dummyT);
fun extract thm_vss thy =
let
val thy' = add_syntax thy;
val {realizes_eqns, typeof_eqns, types, realizers, defs, expand, prep} =
ExtractionData.get thy;
val procs = maps (rev o fst o snd) types;
val rtypes = map fst types;
val typroc = typeof_proc [];
val prep = the_default (K I) prep thy' o ProofRewriteRules.elim_defs thy' false defs o
Reconstruct.expand_proof thy' (map (rpair NONE) ("" :: expand));
val rrews = Net.merge (K false) (#net realizes_eqns, #net typeof_eqns);
fun find_inst prop Ts ts vs =
let
val rvs = relevant_vars rtypes prop;
val vars = vars_of prop;
val n = Int.min (length vars, length ts);
fun add_args (Var ((a, i), _), t) (vs', tye) =
if member (op =) rvs a then
let val T = etype_of thy' vs Ts t
in if T = nullT then (vs', tye)
else (a :: vs', (("'" ^ a, i), T) :: tye)
end
else (vs', tye)
in fold_rev add_args (take n vars ~~ take n ts) ([], []) end;
fun mk_shyps tye = maps (fn (ixn, _) =>
Logic.mk_of_sort (TVar (ixn, []), Sign.defaultS thy)) tye;
fun mk_sprfs cs tye = maps (fn (_, T) =>
ProofRewriteRules.mk_of_sort_proof thy (map SOME cs)
(T, Sign.defaultS thy)) tye;
fun find (vs: string list) = Option.map snd o find_first (curry (eq_set (op =)) vs o fst);
fun find' (s: string) = map_filter (fn (s', x) => if s = s' then SOME x else NONE);
fun app_rlz_rews Ts vs t =
strip_abs (length Ts)
(freeze_thaw (condrew thy' rrews (procs @ [typroc vs, rlz_proc]))
(fold (Term.abs o pair "x") Ts t));
fun realizes_null vs prop = app_rlz_rews [] vs
(Const ("realizes", nullT --> propT --> propT) $ nullt $ prop);
fun corr d vs ts Ts hs cs _ (PBound i) _ defs = (PBound i, defs)
| corr d vs ts Ts hs cs t (Abst (s, SOME T, prf)) (Abst (_, _, prf')) defs =
let val (corr_prf, defs') = corr d vs [] (T :: Ts)
(dummyt :: hs) cs (case t of SOME (Abs (_, _, u)) => SOME u | _ => NONE)
prf (Proofterm.incr_pboundvars 1 0 prf') defs
in (Abst (s, SOME T, corr_prf), defs') end
| corr d vs ts Ts hs cs t (AbsP (s, SOME prop, prf)) (AbsP (_, _, prf')) defs =
let
val T = etype_of thy' vs Ts prop;
val u = if T = nullT then
(case t of SOME u => SOME (incr_boundvars 1 u) | NONE => NONE)
else (case t of SOME (Abs (_, _, u)) => SOME u | _ => NONE);
val (corr_prf, defs') =
corr d vs [] (T :: Ts) (prop :: hs)
(prop :: cs) u (Proofterm.incr_pboundvars 0 1 prf)
(Proofterm.incr_pboundvars 0 1 prf') defs;
val rlz = Const ("realizes", T --> propT --> propT)
in (
if T = nullT then AbsP ("R",
SOME (app_rlz_rews Ts vs (rlz $ nullt $ prop)),
Proofterm.prf_subst_bounds [nullt] corr_prf)
else Abst (s, SOME T, AbsP ("R",
SOME (app_rlz_rews (T :: Ts) vs
(rlz $ Bound 0 $ incr_boundvars 1 prop)), corr_prf)), defs')
end
| corr d vs ts Ts hs cs t' (prf % SOME t) (prf' % _) defs =
let
val (Us, T) = strip_type (fastype_of1 (Ts, t));
val (corr_prf, defs') = corr d vs (t :: ts) Ts hs cs
(if member (op =) rtypes (tname_of T) then t'
else (case t' of SOME (u $ _) => SOME u | _ => NONE))
prf prf' defs;
val u = if not (member (op =) rtypes (tname_of T)) then t else
let
val eT = etype_of thy' vs Ts t;
val (r, Us') = if eT = nullT then (nullt, Us) else
(Bound (length Us), eT :: Us);
val u = list_comb (incr_boundvars (length Us') t,
map Bound (length Us - 1 downto 0));
val u' = (case AList.lookup (op =) types (tname_of T) of
SOME ((_, SOME f)) => f r eT u T
| _ => Const ("realizes", eT --> T --> T) $ r $ u)
in app_rlz_rews Ts vs (fold_rev (Term.abs o pair "x") Us' u') end
in (corr_prf % SOME u, defs') end
| corr d vs ts Ts hs cs t (prf1 %% prf2) (prf1' %% prf2') defs =
let
val prop = Reconstruct.prop_of' hs prf2';
val T = etype_of thy' vs Ts prop;
val (f, u, defs1) = if T = nullT then (t, NONE, defs) else
(case t of
SOME (f $ u) => (SOME f, SOME u, defs)
| _ =>
let val (u, defs1) = extr d vs [] Ts hs prf2' defs
in (NONE, SOME u, defs1) end)
val ((corr_prf1, corr_prf2), defs2) =
defs1
|> corr d vs [] Ts hs cs f prf1 prf1'
||>> corr d vs [] Ts hs cs u prf2 prf2';
in
if T = nullT then (corr_prf1 %% corr_prf2, defs2) else
(corr_prf1 % u %% corr_prf2, defs2)
end
| corr d vs ts Ts hs cs _ (prf0 as PThm (_, ((name, prop, SOME Ts'), body))) _ defs =
let
val prf = Proofterm.join_proof body;
val (vs', tye) = find_inst prop Ts ts vs;
val shyps = mk_shyps tye;
val sprfs = mk_sprfs cs tye;
val tye' = (map fst (Term.add_tvars prop [] |> rev) ~~ Ts') @ tye;
val T = etype_of thy' vs' [] prop;
val defs' = if T = nullT then defs
else snd (extr d vs ts Ts hs prf0 defs)
in
if T = nullT andalso realizes_null vs' prop aconv prop then (prf0, defs)
else (case Symtab.lookup realizers name of
NONE => (case find vs' (find' name defs') of
NONE =>
let
val _ = T = nullT orelse error "corr: internal error";
val _ = msg d ("Building correctness proof for " ^ quote name ^
(if null vs' then ""
else " (relevant variables: " ^ commas_quote vs' ^ ")"));
val prf' = prep (Reconstruct.reconstruct_proof thy' prop prf);
val (corr_prf0, defs'') = corr (d + 1) vs' [] [] []
(rev shyps) NONE prf' prf' defs';
val corr_prf = mkabsp shyps corr_prf0;
val corr_prop = Reconstruct.prop_of corr_prf;
val corr_prf' =
Proofterm.proof_combP (Proofterm.proof_combt
(PThm (serial (),
((corr_name name vs', corr_prop, SOME (map TVar (Term.add_tvars corr_prop [] |> rev))),
Future.value (Proofterm.approximate_proof_body corr_prf))),
vfs_of corr_prop),
map PBound (length shyps - 1 downto 0)) |>
fold_rev Proofterm.forall_intr_proof'
(map (get_var_type corr_prop) (vfs_of prop)) |>
mkabsp shyps
in
(Proofterm.proof_combP (prf_subst_TVars tye' corr_prf', sprfs),
(name, (vs', ((nullt, nullt), (corr_prf, corr_prf')))) :: defs'')
end
| SOME (_, (_, prf')) =>
(Proofterm.proof_combP (prf_subst_TVars tye' prf', sprfs), defs'))
| SOME rs => (case find vs' rs of
SOME (_, prf') => (Proofterm.proof_combP (prf_subst_TVars tye' prf', sprfs), defs')
| NONE => error ("corr: no realizer for instance of theorem " ^
quote name ^ ":\n" ^ Syntax.string_of_term_global thy' (Envir.beta_norm
(Reconstruct.prop_of (Proofterm.proof_combt (prf0, ts)))))))
end
| corr d vs ts Ts hs cs _ (prf0 as PAxm (s, prop, SOME Ts')) _ defs =
let
val (vs', tye) = find_inst prop Ts ts vs;
val tye' = (map fst (Term.add_tvars prop [] |> rev) ~~ Ts') @ tye
in
if etype_of thy' vs' [] prop = nullT andalso
realizes_null vs' prop aconv prop then (prf0, defs)
else case find vs' (Symtab.lookup_list realizers s) of
SOME (_, prf) => (Proofterm.proof_combP (prf_subst_TVars tye' prf, mk_sprfs cs tye),
defs)
| NONE => error ("corr: no realizer for instance of axiom " ^
quote s ^ ":\n" ^ Syntax.string_of_term_global thy' (Envir.beta_norm
(Reconstruct.prop_of (Proofterm.proof_combt (prf0, ts)))))
end
| corr d vs ts Ts hs _ _ _ _ defs = error "corr: bad proof"
and extr d vs ts Ts hs (PBound i) defs = (Bound i, defs)
| extr d vs ts Ts hs (Abst (s, SOME T, prf)) defs =
let val (t, defs') = extr d vs []
(T :: Ts) (dummyt :: hs) (Proofterm.incr_pboundvars 1 0 prf) defs
in (Abs (s, T, t), defs') end
| extr d vs ts Ts hs (AbsP (s, SOME t, prf)) defs =
let
val T = etype_of thy' vs Ts t;
val (t, defs') =
extr d vs [] (T :: Ts) (t :: hs) (Proofterm.incr_pboundvars 0 1 prf) defs
in
(if T = nullT then subst_bound (nullt, t) else Abs (s, T, t), defs')
end
| extr d vs ts Ts hs (prf % SOME t) defs =
let val (u, defs') = extr d vs (t :: ts) Ts hs prf defs
in (if member (op =) rtypes (tname_of (body_type (fastype_of1 (Ts, t)))) then u
else u $ t, defs')
end
| extr d vs ts Ts hs (prf1 %% prf2) defs =
let
val (f, defs') = extr d vs [] Ts hs prf1 defs;
val prop = Reconstruct.prop_of' hs prf2;
val T = etype_of thy' vs Ts prop
in
if T = nullT then (f, defs') else
let val (t, defs'') = extr d vs [] Ts hs prf2 defs'
in (f $ t, defs'') end
end
| extr d vs ts Ts hs (prf0 as PThm (_, ((s, prop, SOME Ts'), body))) defs =
let
val prf = Proofterm.join_proof body;
val (vs', tye) = find_inst prop Ts ts vs;
val shyps = mk_shyps tye;
val tye' = (map fst (Term.add_tvars prop [] |> rev) ~~ Ts') @ tye
in
case Symtab.lookup realizers s of
NONE => (case find vs' (find' s defs) of
NONE =>
let
val _ = msg d ("Extracting " ^ quote s ^
(if null vs' then ""
else " (relevant variables: " ^ commas_quote vs' ^ ")"));
val prf' = prep (Reconstruct.reconstruct_proof thy' prop prf);
val (t, defs') = extr (d + 1) vs' [] [] [] prf' defs;
val (corr_prf, defs'') = corr (d + 1) vs' [] [] []
(rev shyps) (SOME t) prf' prf' defs';
val nt = Envir.beta_norm t;
val args = filter_out (fn v => member (op =) rtypes
(tname_of (body_type (fastype_of v)))) (vfs_of prop);
val args' = filter (fn v => Logic.occs (v, nt)) args;
val t' = mkabs args' nt;
val T = fastype_of t';
val cname = extr_name s vs';
val c = Const (cname, T);
val u = mkabs args (list_comb (c, args'));
val eqn = Logic.mk_equals (c, t');
val rlz =
Const ("realizes", fastype_of nt --> propT --> propT);
val lhs = app_rlz_rews [] vs' (rlz $ nt $ prop);
val rhs = app_rlz_rews [] vs' (rlz $ list_comb (c, args') $ prop);
val f = app_rlz_rews [] vs'
(Abs ("x", T, rlz $ list_comb (Bound 0, args') $ prop));
val corr_prf' = mkabsp shyps
(chtype [] Proofterm.equal_elim_axm %> lhs %> rhs %%
(chtype [propT] Proofterm.symmetric_axm %> rhs %> lhs %%
(chtype [T, propT] Proofterm.combination_axm %> f %> f %> c %> t' %%
(chtype [T --> propT] Proofterm.reflexive_axm %> f) %%
PAxm (Thm.def_name cname, eqn,
SOME (map TVar (Term.add_tvars eqn [] |> rev))))) %% corr_prf);
val corr_prop = Reconstruct.prop_of corr_prf';
val corr_prf'' =
Proofterm.proof_combP (Proofterm.proof_combt
(PThm (serial (),
((corr_name s vs', corr_prop, SOME (map TVar (Term.add_tvars corr_prop [] |> rev))),
Future.value (Proofterm.approximate_proof_body corr_prf'))),
vfs_of corr_prop),
map PBound (length shyps - 1 downto 0)) |>
fold_rev Proofterm.forall_intr_proof'
(map (get_var_type corr_prop) (vfs_of prop)) |>
mkabsp shyps
in
(subst_TVars tye' u,
(s, (vs', ((t', u), (corr_prf', corr_prf'')))) :: defs'')
end
| SOME ((_, u), _) => (subst_TVars tye' u, defs))
| SOME rs => (case find vs' rs of
SOME (t, _) => (subst_TVars tye' t, defs)
| NONE => error ("extr: no realizer for instance of theorem " ^
quote s ^ ":\n" ^ Syntax.string_of_term_global thy' (Envir.beta_norm
(Reconstruct.prop_of (Proofterm.proof_combt (prf0, ts))))))
end
| extr d vs ts Ts hs (prf0 as PAxm (s, prop, SOME Ts')) defs =
let
val (vs', tye) = find_inst prop Ts ts vs;
val tye' = (map fst (Term.add_tvars prop [] |> rev) ~~ Ts') @ tye
in
case find vs' (Symtab.lookup_list realizers s) of
SOME (t, _) => (subst_TVars tye' t, defs)
| NONE => error ("extr: no realizer for instance of axiom " ^
quote s ^ ":\n" ^ Syntax.string_of_term_global thy' (Envir.beta_norm
(Reconstruct.prop_of (Proofterm.proof_combt (prf0, ts)))))
end
| extr d vs ts Ts hs _ defs = error "extr: bad proof";
fun prep_thm vs thm =
let
val thy = Thm.theory_of_thm thm;
val prop = Thm.prop_of thm;
val prf = Thm.proof_of thm;
val name = Thm.derivation_name thm;
val _ = name <> "" orelse error "extraction: unnamed theorem";
val _ = etype_of thy' vs [] prop <> nullT orelse error ("theorem " ^
quote name ^ " has no computational content")
in Reconstruct.reconstruct_proof thy prop prf end;
val defs =
fold (fn (thm, vs) => snd o (extr 0 vs [] [] [] o prep_thm vs) thm)
thm_vss [];
fun add_def (s, (vs, ((t, u), (prf, _)))) thy =
(case Sign.const_type thy (extr_name s vs) of
NONE =>
let
val corr_prop = Reconstruct.prop_of prf;
val ft = Type.legacy_freeze t;
val fu = Type.legacy_freeze u;
val (def_thms, thy') = if t = nullt then ([], thy) else
thy
|> Sign.add_consts [(Binding.qualified_name (extr_name s vs), fastype_of ft, NoSyn)]
|> Global_Theory.add_defs false
[((Binding.qualified_name (Thm.def_name (extr_name s vs)),
Logic.mk_equals (head_of (strip_abs_body fu), ft)), [])]
in
thy'
|> Global_Theory.store_thm (Binding.qualified_name (corr_name s vs),
Thm.varifyT_global (funpow (length (vars_of corr_prop))
(Thm.forall_elim_var 0) (Thm.forall_intr_frees
(Proof_Checker.thm_of_proof thy'
(fst (Proofterm.freeze_thaw_prf prf))))))
|> snd
|> fold Code.add_default_eqn def_thms
end
| SOME _ => thy);
in
thy
|> Sign.root_path
|> fold_rev add_def defs
|> Sign.restore_naming thy
end;
val etype_of = etype_of o add_syntax;
end;