|
(* Title: Pure/term_sharing.ML
Author: Makarius
Local sharing of type/term sub-structure, with global interning of
formal entity names.
*)
signature TERM_SHARING =
sig
val init: theory -> (typ -> typ) * (term -> term)
val typs: theory -> typ list -> typ list
val terms: theory -> term list -> term list
end;
structure Term_Sharing: TERM_SHARING =
struct
structure Syntax_Termtab = Table(type key = term val ord = Term_Ord.syntax_term_ord);
fun init thy =
let
val {classes = (_, algebra), types, ...} = Type.rep_tsig (Sign.tsig_of thy);
val class = perhaps (try (#1 o Graph.get_entry (Sorts.classes_of algebra)));
val tycon = perhaps (Option.map #1 o Name_Space.lookup_key types);
val const = perhaps (try (#1 o Consts.the_const (Sign.consts_of thy)));
val typs = Unsynchronized.ref (Typtab.empty: unit Typtab.table);
val terms = Unsynchronized.ref (Syntax_Termtab.empty: unit Syntax_Termtab.table);
fun typ T =
(case Typtab.lookup_key (! typs) T of
SOME (T', ()) => T'
| NONE =>
let
val T' =
(case T of
Type (a, Ts) => Type (tycon a, map typ Ts)
| TFree (a, S) => TFree (a, map class S)
| TVar (a, S) => TVar (a, map class S));
val _ = Unsynchronized.change typs (Typtab.update (T', ()));
in T' end);
fun term tm =
(case Syntax_Termtab.lookup_key (! terms) tm of
SOME (tm', ()) => tm'
| NONE =>
let
val tm' =
(case tm of
Const (c, T) => Const (const c, typ T)
| Free (x, T) => Free (x, typ T)
| Var (xi, T) => Var (xi, typ T)
| Bound i => Bound i
| Abs (x, T, t) => Abs (x, typ T, term t)
| t $ u => term t $ term u);
val _ = Unsynchronized.change terms (Syntax_Termtab.update (tm', ()));
in tm' end);
fun check eq f x =
let val x' = f x in
if eq (x, x') then x'
else raise Fail "Something is utterly wrong"
end;
in (check (op =) typ, check (op =) term) end;
val typs = map o #1 o init;
val terms = map o #2 o init;
end;
¤ Dauer der Verarbeitung: 0.2 Sekunden
(vorverarbeitet)
¤
|
Haftungshinweis
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung ist noch experimentell.
|
