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(* Title: Pure/more_pattern.ML
Author: Tobias Nipkow, TU Muenchen
Author: Stefan Berghofer, TU Muenchen
Add-ons to Higher-Order Patterns, outside the inference kernel.
*)
signature PATTERN =
sig
include PATTERN
val matches: theory -> term * term -> bool
val matchess: theory -> term list * term list -> bool
val equiv: theory -> term * term -> bool
val first_order: term -> bool
val match_rew: theory -> term -> term * term -> (term * term) option
val rewrite_term: theory -> (term * term) list -> (term -> term option) list -> term -> term
val rewrite_term_top: theory -> (term * term) list -> (term -> term option) list -> term -> term
end;
structure Pattern: PATTERN =
struct
fun matches thy po =
(Pattern.match thy po (Vartab.empty, Vartab.empty); true) handle Pattern.MATCH => false;
fun matchess thy (ps, os) =
length ps = length os andalso
((fold (Pattern.match thy) (ps ~~ os) (Vartab.empty, Vartab.empty); true)
handle Pattern.MATCH => false);
fun equiv thy (t, u) = matches thy (t, u) andalso matches thy (u, t);
fun first_order (Abs (_, _, t)) = first_order t
| first_order (Var _ $ _) = false
| first_order (t $ u) = first_order t andalso first_order u
| first_order _ = true;
(* rewriting -- simple but fast *)
fun match_rew thy tm (tm1, tm2) =
let val rtm = the_default tm2 (Term.rename_abs tm1 tm tm2) in
SOME (Envir.subst_term (Pattern.match thy (tm1, tm) (Vartab.empty, Vartab.empty)) rtm, rtm)
handle Pattern.MATCH => NONE
end;
fun gen_rewrite_term bot thy rules procs tm =
let
val skel0 = Bound 0;
fun variant_absfree bounds (x, T, t) =
let
val (x', t') = Term.dest_abs (Name.bound bounds, T, t);
fun abs u = Abs (x, T, abstract_over (Free (x', T), u));
in (abs, t') end;
fun rew (Abs (_, _, body) $ t) = SOME (subst_bound (t, body), skel0)
| rew tm =
(case get_first (match_rew thy tm) rules of
NONE => Option.map (rpair skel0) (get_first (fn p => p tm) procs)
| x => x);
fun rew_sub r bounds skel (tm1 $ tm2) = (case tm1 of
Abs (_, _, body) =>
let val tm' = subst_bound (tm2, body)
in SOME (the_default tm' (rew_sub r bounds skel0 tm')) end
| _ =>
let val (skel1, skel2) = (case skel of
skel1 $ skel2 => (skel1, skel2)
| _ => (skel0, skel0))
in case r bounds skel1 tm1 of
SOME tm1' => (case r bounds skel2 tm2 of
SOME tm2' => SOME (tm1' $ tm2')
| NONE => SOME (tm1' $ tm2))
| NONE => (case r bounds skel2 tm2 of
SOME tm2' => SOME (tm1 $ tm2')
| NONE => NONE)
end)
| rew_sub r bounds skel (Abs body) =
let
val (abs, tm') = variant_absfree bounds body;
val skel' = (case skel of Abs (_, _, skel') => skel' | _ => skel0)
in case r (bounds + 1) skel' tm' of
SOME tm'' => SOME (abs tm'')
| NONE => NONE
end
| rew_sub _ _ _ _ = NONE;
fun rew_bot bounds (Var _) _ = NONE
| rew_bot bounds skel tm = (case rew_sub rew_bot bounds skel tm of
SOME tm1 => (case rew tm1 of
SOME (tm2, skel') => SOME (the_default tm2 (rew_bot bounds skel' tm2))
| NONE => SOME tm1)
| NONE => (case rew tm of
SOME (tm1, skel') => SOME (the_default tm1 (rew_bot bounds skel' tm1))
| NONE => NONE));
fun rew_top bounds _ tm = (case rew tm of
SOME (tm1, _) => (case rew_sub rew_top bounds skel0 tm1 of
SOME tm2 => SOME (the_default tm2 (rew_top bounds skel0 tm2))
| NONE => SOME tm1)
| NONE => (case rew_sub rew_top bounds skel0 tm of
SOME tm1 => SOME (the_default tm1 (rew_top bounds skel0 tm1))
| NONE => NONE));
in the_default tm ((if bot then rew_bot else rew_top) 0 skel0 tm) end;
val rewrite_term = gen_rewrite_term true;
val rewrite_term_top = gen_rewrite_term false;
open Pattern;
end;
¤ Dauer der Verarbeitung: 0.3 Sekunden
(vorverarbeitet)
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