(* Title: Pure/Isar/overloading.ML
Author: Florian Haftmann, TU Muenchen
Overloaded definitions without any discipline.
*)
signature OVERLOADING =
sig
type improvable_syntax
val activate_improvable_syntax: Proof.context -> Proof.context
val map_improvable_syntax: (improvable_syntax -> improvable_syntax)
-> Proof.context -> Proof.context
val set_primary_constraints: Proof.context -> Proof.context
val overloading: (string * (string * typ) * bool) list -> theory -> local_theory
val overloading_cmd: (string * string * bool) list -> theory -> local_theory
end;
structure Overloading: OVERLOADING =
struct
(** generic check/uncheck combinators for improvable constants **)
type improvable_syntax = ((((string * typ) list * (string * typ) list) *
((((string * typ -> (typ * typ) option) * (string * typ -> (typ * term) option)) * bool) *
(term * term) list)) * bool);
structure ImprovableSyntax = Proof_Data
(
type T = {
primary_constraints: (string * typ) list,
secondary_constraints: (string * typ) list,
improve: string * typ -> (typ * typ) option,
subst: string * typ -> (typ * term) option,
consider_abbrevs: bool,
unchecks: (term * term) list,
passed: bool
};
fun init _ = {
primary_constraints = [],
secondary_constraints = [],
improve = K NONE,
subst = K NONE,
consider_abbrevs = false,
unchecks = [],
passed = true
};
);
fun map_improvable_syntax f = ImprovableSyntax.map (fn { primary_constraints,
secondary_constraints, improve, subst, consider_abbrevs, unchecks, passed } => let
val (((primary_constraints', secondary_constraints'),
(((improve', subst'), consider_abbrevs'), unchecks')), passed')
= f (((primary_constraints, secondary_constraints),
(((improve, subst), consider_abbrevs), unchecks)), passed)
in { primary_constraints = primary_constraints', secondary_constraints = secondary_constraints',
improve = improve', subst = subst', consider_abbrevs = consider_abbrevs',
unchecks = unchecks', passed = passed'
} end);
val mark_passed = (map_improvable_syntax o apsnd) (K true);
fun improve_term_check ts ctxt =
let
val { secondary_constraints, improve, subst, consider_abbrevs, passed, ... } =
ImprovableSyntax.get ctxt;
val tsig = (Sign.tsig_of o ProofContext.theory_of) ctxt;
val is_abbrev = consider_abbrevs andalso ProofContext.abbrev_mode ctxt;
val passed_or_abbrev = passed orelse is_abbrev;
fun accumulate_improvements (Const (c, ty)) = (case improve (c, ty)
of SOME ty_ty' => Type.typ_match tsig ty_ty'
| _ => I)
| accumulate_improvements _ = I;
val improvements = (fold o fold_aterms) accumulate_improvements ts Vartab.empty;
val ts' = (map o map_types) (Envir.subst_type improvements) ts;
fun apply_subst t = Envir.expand_term (fn Const (c, ty) => (case subst (c, ty)
of SOME (ty', t') =>
if Type.typ_instance tsig (ty, ty')
then SOME (ty', apply_subst t') else NONE
| NONE => NONE)
| _ => NONE) t;
val ts'' = if is_abbrev then ts' else map apply_subst ts';
in if eq_list (op aconv) (ts, ts'') andalso passed_or_abbrev then NONE else
if passed_or_abbrev then SOME (ts'', ctxt)
else SOME (ts'', ctxt
|> fold (ProofContext.add_const_constraint o apsnd SOME) secondary_constraints
|> mark_passed)
end;
fun rewrite_liberal thy unchecks t =
case try (Pattern.rewrite_term thy unchecks []) t
of NONE => NONE
| SOME t' => if t aconv t' then NONE else SOME t';
fun improve_term_uncheck ts ctxt =
let
val thy = ProofContext.theory_of ctxt;
val unchecks = (#unchecks o ImprovableSyntax.get) ctxt;
val ts' = map (rewrite_liberal thy unchecks) ts;
in if exists is_some ts' then SOME (map2 the_default ts ts', ctxt) else NONE end;
fun set_primary_constraints ctxt =
let
val { primary_constraints, ... } = ImprovableSyntax.get ctxt;
in fold (ProofContext.add_const_constraint o apsnd SOME) primary_constraints ctxt end;
val activate_improvable_syntax =
Context.proof_map
(Syntax.add_term_check 0 "improvement" improve_term_check
#> Syntax.add_term_uncheck 0 "improvement" improve_term_uncheck)
#> set_primary_constraints;
(** overloading target **)
structure Data = Proof_Data
(
type T = ((string * typ) * (string * bool)) list;
fun init _ = [];
);
val get_overloading = Data.get o Local_Theory.target_of;
val map_overloading = Local_Theory.target o Data.map;
fun operation lthy b = get_overloading lthy
|> get_first (fn ((c, _), (v, checked)) =>
if Binding.name_of b = v then SOME (c, (v, checked)) else NONE);
fun synchronize_syntax ctxt =
let
val overloading = Data.get ctxt;
fun subst (c, ty) = case AList.lookup (op =) overloading (c, ty)
of SOME (v, _) => SOME (ty, Free (v, ty))
| NONE => NONE;
val unchecks =
map (fn (c_ty as (_, ty), (v, _)) => (Free (v, ty), Const c_ty)) overloading;
in
ctxt
|> map_improvable_syntax (K ((([], []), (((K NONE, subst), false), unchecks)), false))
end
fun define_overloaded (c, U) (v, checked) (b_def, rhs) =
Local_Theory.background_theory_result
(Thm.add_def (not checked) true (b_def, Logic.mk_equals (Const (c, Term.fastype_of rhs), rhs)))
##> map_overloading (filter_out (fn (_, (v', _)) => v' = v))
##> Local_Theory.target synchronize_syntax
#-> (fn (_, def) => pair (Const (c, U), def))
fun foundation (((b, U), mx), (b_def, rhs)) (type_params, term_params) lthy =
case operation lthy b
of SOME (c, (v, checked)) => if mx <> NoSyn
then error ("Illegal mixfix syntax for overloaded constant " ^ quote c)
else lthy |> define_overloaded (c, U) (v, checked) (b_def, rhs)
| NONE => lthy |>
Generic_Target.theory_foundation (((b, U), mx), (b_def, rhs)) (type_params, term_params);
fun pretty lthy =
let
val thy = ProofContext.theory_of lthy;
val overloading = get_overloading lthy;
fun pr_operation ((c, ty), (v, _)) =
(Pretty.block o Pretty.breaks) [Pretty.str v, Pretty.str "==",
Pretty.str (Sign.extern_const thy c), Pretty.str "::", Syntax.pretty_typ lthy ty];
in Pretty.str "overloading" :: map pr_operation overloading end;
fun conclude lthy =
let
val overloading = get_overloading lthy;
val _ = if null overloading then () else
error ("Missing definition(s) for parameter(s) " ^ commas (map (quote
o Syntax.string_of_term lthy o Const o fst) overloading));
in lthy end;
fun gen_overloading prep_const raw_overloading thy =
let
val ctxt = ProofContext.init_global thy;
val _ = if null raw_overloading then error "At least one parameter must be given" else ();
val overloading = raw_overloading |> map (fn (v, const, checked) =>
(Term.dest_Const (prep_const ctxt const), (v, checked)));
in
thy
|> Theory.checkpoint
|> ProofContext.init_global
|> Data.put overloading
|> fold (fn ((_, ty), (v, _)) => Variable.declare_names (Free (v, ty))) overloading
|> activate_improvable_syntax
|> synchronize_syntax
|> Local_Theory.init NONE ""
{define = Generic_Target.define foundation,
notes = Generic_Target.notes
(fn kind => fn global_facts => fn _ => Generic_Target.theory_notes kind global_facts),
abbrev = Generic_Target.abbrev
(fn prmode => fn (b, mx) => fn (t, _) => fn _ =>
Generic_Target.theory_abbrev prmode ((b, mx), t)),
declaration = K Generic_Target.theory_declaration,
syntax_declaration = K Generic_Target.theory_declaration,
pretty = pretty,
exit = Local_Theory.target_of o conclude}
end;
val overloading = gen_overloading (fn ctxt => Syntax.check_term ctxt o Const);
val overloading_cmd = gen_overloading Syntax.read_term;
end;