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(* Title: HOL/Tools/code_evaluation.ML
Author: Florian Haftmann, TU Muenchen
Evaluation and reconstruction of terms in ML.
*)
signature CODE_EVALUATION =
sig
val dynamic_value: Proof.context -> term -> term option
val dynamic_value_strict: Proof.context -> term -> term
val dynamic_value_exn: Proof.context -> term -> term Exn.result
val put_term: (unit -> term) -> Proof.context -> Proof.context
val tracing: string -> 'a -> 'a
end;
structure Code_Evaluation : CODE_EVALUATION =
struct
(** term_of instances **)
(* formal definition *)
fun add_term_of_inst tyco thy =
let
val ((raw_vs, _), _) = Code.get_type thy tyco;
val vs = map (fn (v, _) => (v, \<^sort>\<open>typerep\<close>)) raw_vs;
val ty = Type (tyco, map TFree vs);
val lhs = Const (\<^const_name>\<open>term_of\<close>, ty --> \<^typ>\<open>term\<close>) $ Free ("x", ty);
val rhs = \<^term>\<open>undefined :: term\<close>;
val eq = HOLogic.mk_Trueprop (HOLogic.mk_eq (lhs, rhs));
fun triv_name_of t = (fst o dest_Free o fst o strip_comb o fst
o HOLogic.dest_eq o HOLogic.dest_Trueprop) t ^ "_triv";
in
thy
|> Class.instantiation ([tyco], vs, \<^sort>\<open>term_of\<close>)
|> `(fn lthy => Syntax.check_term lthy eq)
|-> (fn eq => Specification.definition NONE [] [] ((Binding.name (triv_name_of eq), []), eq))
|> snd
|> Class.prove_instantiation_exit (fn ctxt => Class.intro_classes_tac ctxt [])
end;
fun ensure_term_of_inst tyco thy =
let
val need_inst = not (Sorts.has_instance (Sign.classes_of thy) tyco \<^sort>\<open>term_of\<close>)
andalso Sorts.has_instance (Sign.classes_of thy) tyco \<^sort>\<open>typerep\<close>;
in if need_inst then add_term_of_inst tyco thy else thy end;
fun for_term_of_instance tyco vs f thy =
let
val algebra = Sign.classes_of thy;
in
case try (Sorts.mg_domain algebra tyco) \<^sort>\<open>term_of\<close> of
NONE => thy
| SOME sorts => f tyco (map2 (fn (v, sort) => fn sort' =>
(v, Sorts.inter_sort algebra (sort, sort'))) vs sorts) thy
end;
(* code equations for datatypes *)
fun mk_term_of_eq thy ty (c, (_, tys)) =
let
val t = list_comb (Const (c, tys ---> ty),
map Free (Name.invent_names Name.context "a" tys));
val (arg, rhs) =
apply2 (Thm.global_cterm_of thy o Logic.unvarify_types_global o Logic.varify_global)
(t,
map_aterms (fn t as Free (_, ty) => HOLogic.mk_term_of ty t | t => t)
(HOLogic.reflect_term t));
val cty = Thm.global_ctyp_of thy ty;
in
@{thm term_of_anything}
|> Thm.instantiate' [SOME cty] [SOME arg, SOME rhs]
|> Thm.varifyT_global
end;
fun add_term_of_code_datatype tyco vs raw_cs thy =
let
val ty = Type (tyco, map TFree vs);
val cs = (map o apsnd o apsnd o map o map_atyps)
(fn TFree (v, _) => TFree (v, (the o AList.lookup (op =) vs) v)) raw_cs;
val eqs = map (mk_term_of_eq thy ty) cs;
in
thy
|> Code.declare_default_eqns_global (map (rpair true) eqs)
end;
fun ensure_term_of_code_datatype (tyco, (vs, cs)) =
for_term_of_instance tyco vs (fn tyco => fn vs => add_term_of_code_datatype tyco vs cs);
(* code equations for abstypes *)
fun mk_abs_term_of_eq thy ty abs ty_rep proj =
let
val arg = Var (("x", 0), ty);
val rhs = Abs ("y", \<^typ>\<open>term\<close>, HOLogic.reflect_term (Const (abs, ty_rep --> ty) $ Bound 0)) $
(HOLogic.mk_term_of ty_rep (Const (proj, ty --> ty_rep) $ arg))
|> Thm.global_cterm_of thy;
val cty = Thm.global_ctyp_of thy ty;
in
@{thm term_of_anything}
|> Thm.instantiate' [SOME cty] [SOME (Thm.global_cterm_of thy arg), SOME rhs]
|> Thm.varifyT_global
end;
fun add_term_of_code_abstype tyco vs abs raw_ty_rep projection thy =
let
val ty = Type (tyco, map TFree vs);
val ty_rep = map_atyps
(fn TFree (v, _) => TFree (v, (the o AList.lookup (op =) vs) v)) raw_ty_rep;
val eq = mk_abs_term_of_eq thy ty abs ty_rep projection;
in
thy
|> Code.declare_default_eqns_global [(eq, true)]
end;
fun ensure_term_of_code_abstype (tyco, (vs, {abstractor = (abs, (_, ty)),
projection, ...})) =
for_term_of_instance tyco vs
(fn tyco => fn vs => add_term_of_code_abstype tyco vs abs ty projection);
(* setup *)
val _ = Theory.setup
(Code.type_interpretation ensure_term_of_inst
#> Code.datatype_interpretation ensure_term_of_code_datatype
#> Code.abstype_interpretation ensure_term_of_code_abstype);
(** termifying syntax **)
fun map_default f xs =
let val ys = map f xs
in if exists is_some ys
then SOME (map2 the_default xs ys)
else NONE
end;
fun subst_termify_app (Const (\<^const_name>\<open>termify\<close>, _), [t]) =
if not (Term.exists_subterm (fn Abs _ => true | _ => false) t)
then if fold_aterms (fn Const _ => I | _ => K false) t true
then SOME (HOLogic.reflect_term t)
else error "Cannot termify expression containing variable"
else error "Cannot termify expression containing abstraction"
| subst_termify_app (t, ts) = case map_default subst_termify ts
of SOME ts' => SOME (list_comb (t, ts'))
| NONE => NONE
and subst_termify (Abs (v, T, t)) = (case subst_termify t
of SOME t' => SOME (Abs (v, T, t'))
| NONE => NONE)
| subst_termify t = subst_termify_app (strip_comb t)
fun check_termify ts = the_default ts (map_default subst_termify ts);
val _ = Context.>> (Syntax_Phases.term_check 0 "termify" (K check_termify));
(** evaluation **)
structure Evaluation = Proof_Data
(
type T = unit -> term
val empty: T = fn () => raise Fail "Evaluation"
fun init _ = empty
);
val put_term = Evaluation.put;
val cookie = (Evaluation.get, put_term, "Code_Evaluation.put_term");
fun mk_term_of t = HOLogic.mk_term_of (fastype_of t) t;
fun gen_dynamic_value computation ctxt t =
computation cookie ctxt NONE I (mk_term_of t) [];
val dynamic_value = gen_dynamic_value Code_Runtime.dynamic_value;
val dynamic_value_strict = gen_dynamic_value Code_Runtime.dynamic_value_strict;
val dynamic_value_exn = gen_dynamic_value Code_Runtime.dynamic_value_exn;
(** diagnostic **)
fun tracing s x = (Output.tracing s; x);
end;
¤ Dauer der Verarbeitung: 0.16 Sekunden
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