--- a/src/Pure/thm.ML Fri Oct 27 15:53:47 2000 +0200
+++ b/src/Pure/thm.ML Fri Oct 27 16:25:21 2000 +0200
@@ -28,15 +28,10 @@
val read_cterm : Sign.sg -> string * typ -> cterm
val cterm_fun : (term -> term) -> (cterm -> cterm)
val dest_comb : cterm -> cterm * cterm
- val dest_abs : string option -> cterm -> cterm * cterm
+ val dest_abs : cterm -> cterm * cterm
val adjust_maxidx : cterm -> cterm
val capply : cterm -> cterm -> cterm
val cabs : cterm -> cterm -> cterm
- val cterm_match : cterm * cterm ->
- (indexname * ctyp) list * (cterm * cterm) list
- val cterm_first_order_match : cterm * cterm ->
- (indexname * ctyp) list * (cterm * cterm) list
- val cterm_incr_indexes : int -> cterm -> cterm
val read_def_cterm :
Sign.sg * (indexname -> typ option) * (indexname -> sort option) ->
string list -> bool -> string * typ -> cterm * (indexname * typ) list
@@ -64,7 +59,6 @@
| Symmetric
| Transitive
| Beta_conversion of cterm
- | Eta_conversion of cterm
| Extensional
| Abstract_rule of string * cterm
| Combination
@@ -123,8 +117,7 @@
val reflexive : cterm -> thm
val symmetric : thm -> thm
val transitive : thm -> thm -> thm
- val beta_conversion : bool -> cterm -> thm
- val eta_conversion : cterm -> thm
+ val beta_conversion : cterm -> thm
val extensional : thm -> thm
val abstract_rule : string -> cterm -> thm -> thm
val combination : thm -> thm -> thm
@@ -142,7 +135,6 @@
val dest_state : thm * int ->
(term * term) list * term list * term * term
val lift_rule : (thm * int) -> thm -> thm
-(* val incr_indexes : int -> thm -> thm*)
val assumption : int -> thm -> thm Seq.seq
val eq_assumption : int -> thm -> thm
val rotate_rule : int -> int -> thm -> thm
@@ -152,6 +144,37 @@
int -> thm -> thm Seq.seq
val biresolution : bool -> (bool * thm) list ->
int -> thm -> thm Seq.seq
+
+ (*meta simplification*)
+ exception SIMPLIFIER of string * thm
+ type meta_simpset
+ val dest_mss : meta_simpset ->
+ {simps: thm list, congs: thm list, procs: (string * cterm list) list}
+ val empty_mss : meta_simpset
+ val clear_mss : meta_simpset -> meta_simpset
+ val merge_mss : meta_simpset * meta_simpset -> meta_simpset
+ val add_simps : meta_simpset * thm list -> meta_simpset
+ val del_simps : meta_simpset * thm list -> meta_simpset
+ val mss_of : thm list -> meta_simpset
+ val add_congs : meta_simpset * thm list -> meta_simpset
+ val del_congs : meta_simpset * thm list -> meta_simpset
+ val add_simprocs : meta_simpset *
+ (string * cterm list * (Sign.sg -> thm list -> term -> thm option) * stamp) list
+ -> meta_simpset
+ val del_simprocs : meta_simpset *
+ (string * cterm list * (Sign.sg -> thm list -> term -> thm option) * stamp) list
+ -> meta_simpset
+ val add_prems : meta_simpset * thm list -> meta_simpset
+ val prems_of_mss : meta_simpset -> thm list
+ val set_mk_rews : meta_simpset * (thm -> thm list) -> meta_simpset
+ val set_mk_sym : meta_simpset * (thm -> thm option) -> meta_simpset
+ val set_mk_eq_True : meta_simpset * (thm -> thm option) -> meta_simpset
+ val set_termless : meta_simpset * (term * term -> bool) -> meta_simpset
+ val trace_simp : bool ref
+ val debug_simp : bool ref
+ val rewrite_cterm : bool * bool * bool -> meta_simpset ->
+ (meta_simpset -> thm -> thm option) -> cterm -> thm
+
val invoke_oracle : theory -> xstring -> Sign.sg * Object.T -> thm
end;
@@ -168,11 +191,6 @@
val name_of_thm : thm -> string
val tags_of_thm : thm -> tag list
val name_thm : string * thm -> thm
- val match_bvs : term * term * (string * string) list -> (string * string) list
- val add_typ_sorts : typ * sort list -> sort list
- val add_typs_sorts : typ list * sort list -> sort list
- val add_term_sorts : term * sort list -> sort list
- val add_terms_sorts : term list * sort list -> sort list
end;
structure Thm: THM =
@@ -240,12 +258,12 @@
| dest_comb _ = raise CTERM "dest_comb";
(*Destruct abstraction in cterms*)
-fun dest_abs a (Cterm {sign_ref, T as Type("fun",[_,S]), maxidx, t=Abs(x,ty,M)}) =
- let val (y,N) = variant_abs (if_none a x,ty,M)
+fun dest_abs (Cterm {sign_ref, T as Type("fun",[_,S]), maxidx, t=Abs(x,ty,M)}) =
+ let val (y,N) = variant_abs (x,ty,M)
in (Cterm {sign_ref = sign_ref, T = ty, maxidx = 0, t = Free(y,ty)},
Cterm {sign_ref = sign_ref, T = S, maxidx = maxidx, t = N})
end
- | dest_abs _ _ = raise CTERM "dest_abs";
+ | dest_abs _ = raise CTERM "dest_abs";
(*Makes maxidx precise: it is often too big*)
fun adjust_maxidx (ct as Cterm {sign_ref, T, t, maxidx, ...}) =
@@ -267,33 +285,6 @@
T = ty --> T2, maxidx=Int.max(maxidx1, maxidx2)}
| cabs _ _ = raise CTERM "cabs: first arg is not a free variable";
-(*Matching of cterms*)
-fun gen_cterm_match mtch
- (Cterm {sign_ref = sign_ref1, maxidx = maxidx1, t = t1, ...},
- Cterm {sign_ref = sign_ref2, maxidx = maxidx2, t = t2, ...}) =
- let
- val sign_ref = Sign.merge_refs (sign_ref1, sign_ref2);
- val tsig = Sign.tsig_of (Sign.deref sign_ref);
- val (Tinsts, tinsts) = mtch tsig (t1, t2);
- val maxidx = Int.max (maxidx1, maxidx2);
- val vars = map dest_Var (term_vars t1);
- fun mk_cTinsts (ixn, T) = (ixn, Ctyp {sign_ref = sign_ref, T = T});
- fun mk_ctinsts (ixn, t) =
- let val T = typ_subst_TVars Tinsts (the (assoc (vars, ixn)))
- in
- (Cterm {sign_ref = sign_ref, maxidx = maxidx, T = T, t = Var (ixn, T)},
- Cterm {sign_ref = sign_ref, maxidx = maxidx, T = T, t = t})
- end;
- in (map mk_cTinsts Tinsts, map mk_ctinsts tinsts) end;
-
-val cterm_match = gen_cterm_match Pattern.match;
-val cterm_first_order_match = gen_cterm_match Pattern.first_order_match;
-
-(*Incrementing indexes*)
-fun cterm_incr_indexes i (Cterm {sign_ref, maxidx, t, T}) =
- Cterm {sign_ref = sign_ref, maxidx = maxidx + i,
- t = Logic.incr_indexes ([], i) t, T = Term.incr_tvar i T};
-
(** read cterms **) (*exception ERROR*)
@@ -340,7 +331,6 @@
| Symmetric
| Transitive
| Beta_conversion of cterm
- | Eta_conversion of cterm
| Extensional
| Abstract_rule of string * cterm
| Combination
@@ -538,9 +528,6 @@
Vartab.foldl (add_term_sorts o swap o apsnd snd)
(Vartab.foldl (add_typ_sorts o swap o apsnd snd) (Ss, iTs), asol);
-fun add_insts_sorts ((iTs, is), Ss) =
- add_typs_sorts (map snd iTs, add_terms_sorts (map snd is, Ss));
-
fun add_thm_sorts (Thm {hyps, prop, ...}, Ss) =
add_terms_sorts (hyps, add_term_sorts (prop, Ss));
@@ -707,17 +694,17 @@
-------
A ==> B
*)
-fun implies_intr cA (thB as Thm{sign_ref,der,maxidx,hyps,shyps,prop}) : thm =
+fun implies_intr cA (thB as Thm{sign_ref,der,maxidx,hyps,prop,...}) : thm =
let val Cterm {sign_ref=sign_refA, t=A, T, maxidx=maxidxA} = cA
in if T<>propT then
raise THM("implies_intr: assumptions must have type prop", 0, [thB])
- else
- Thm{sign_ref = Sign.merge_refs (sign_ref,sign_refA),
+ else fix_shyps [thB] []
+ (Thm{sign_ref = Sign.merge_refs (sign_ref,sign_refA),
der = infer_derivs (Implies_intr cA, [der]),
maxidx = Int.max(maxidxA, maxidx),
- shyps = add_term_sorts (A, shyps),
+ shyps = [],
hyps = disch(hyps,A),
- prop = implies$A$prop}
+ prop = implies$A$prop})
handle TERM _ =>
raise THM("implies_intr: incompatible signatures", 0, [thB])
end;
@@ -729,19 +716,19 @@
B
*)
fun implies_elim thAB thA : thm =
- let val Thm{maxidx=maxA, der=derA, hyps=hypsA, shyps=shypsA, prop=propA, ...} = thA
- and Thm{der, maxidx, hyps, shyps, prop, ...} = thAB;
+ let val Thm{maxidx=maxA, der=derA, hyps=hypsA, prop=propA,...} = thA
+ and Thm{sign_ref, der, maxidx, hyps, prop,...} = thAB;
fun err(a) = raise THM("implies_elim: "^a, 0, [thAB,thA])
in case prop of
imp$A$B =>
if imp=implies andalso A aconv propA
- then
- Thm{sign_ref= merge_thm_sgs(thAB,thA),
- der = infer_derivs (Implies_elim, [der,derA]),
- maxidx = Int.max(maxA,maxidx),
- shyps = union_sort (shypsA, shyps),
- hyps = union_term(hypsA,hyps), (*dups suppressed*)
- prop = B}
+ then fix_shyps [thAB, thA] []
+ (Thm{sign_ref= merge_thm_sgs(thAB,thA),
+ der = infer_derivs (Implies_elim, [der,derA]),
+ maxidx = Int.max(maxA,maxidx),
+ shyps = [],
+ hyps = union_term(hypsA,hyps), (*dups suppressed*)
+ prop = B})
else err("major premise")
| _ => err("major premise")
end;
@@ -834,19 +821,20 @@
t1==t2
*)
fun transitive th1 th2 =
- let val Thm{der=der1, maxidx=max1, hyps=hyps1, shyps=shyps1, prop=prop1,...} = th1
- and Thm{der=der2, maxidx=max2, hyps=hyps2, shyps=shyps2, prop=prop2,...} = th2;
+ let val Thm{der=der1, maxidx=max1, hyps=hyps1, prop=prop1,...} = th1
+ and Thm{der=der2, maxidx=max2, hyps=hyps2, prop=prop2,...} = th2;
fun err(msg) = raise THM("transitive: "^msg, 0, [th1,th2])
in case (prop1,prop2) of
((eq as Const("==",_)) $ t1 $ u, Const("==",_) $ u' $ t2) =>
if not (u aconv u') then err"middle term"
else let val thm =
- Thm{sign_ref= merge_thm_sgs(th1,th2),
+ fix_shyps [th1, th2] []
+ (Thm{sign_ref= merge_thm_sgs(th1,th2),
der = infer_derivs (Transitive, [der1, der2]),
maxidx = Int.max(max1,max2),
- shyps = union_sort (shyps1, shyps2),
+ shyps = [],
hyps = union_term(hyps1,hyps2),
- prop = eq$t1$t2}
+ prop = eq$t1$t2})
in if max1 >= 0 andalso max2 >= 0
then nodup_vars thm "transitive"
else thm (*no new Vars: no expensive check!*)
@@ -854,32 +842,18 @@
| _ => err"premises"
end;
-(*Beta-conversion: maps (%x.t)(u) to the theorem (%x.t)(u) == t[u/x]
- Fully beta-reduces the term if full=true
-*)
-fun beta_conversion full ct =
+(*Beta-conversion: maps (%x.t)(u) to the theorem (%x.t)(u) == t[u/x] *)
+fun beta_conversion ct =
let val Cterm {sign_ref, t, T, maxidx} = ct
- in fix_shyps [] [] (Thm
- {sign_ref = sign_ref,
- der = infer_derivs (Beta_conversion ct, []),
- maxidx = maxidx,
- shyps = [],
- hyps = [],
- prop = Logic.mk_equals (t, if full then Envir.norm_term (Envir.empty 0) t
- else case t of
- Abs(_, _, bodt) $ u => subst_bound (u, bodt)
- | _ => raise THM ("beta_conversion: not a redex", 0, []))})
- end;
-
-fun eta_conversion ct =
- let val Cterm {sign_ref, t, T, maxidx} = ct
- in fix_shyps [] [] (Thm
- {sign_ref = sign_ref,
- der = infer_derivs (Eta_conversion ct, []),
- maxidx = maxidx,
- shyps = [],
- hyps = [],
- prop = Logic.mk_equals (t, Pattern.eta_contract t)})
+ in case t of
+ Abs(_,_,bodt) $ u => fix_shyps [] []
+ (Thm{sign_ref = sign_ref,
+ der = infer_derivs (Beta_conversion ct, []),
+ maxidx = maxidx,
+ shyps = [],
+ hyps = [],
+ prop = Logic.mk_equals(t, subst_bound (u,bodt))})
+ | _ => raise THM("beta_conversion: not a redex", 0, [])
end;
(*The extensionality rule (proviso: x not free in f, g, or hypotheses)
@@ -916,19 +890,19 @@
------------
%x.t == %x.u
*)
-fun abstract_rule a cx (th as Thm{sign_ref,der,maxidx,hyps,shyps,prop}) =
+fun abstract_rule a cx (th as Thm{sign_ref,der,maxidx,hyps,prop,...}) =
let val x = term_of cx;
val (t,u) = Logic.dest_equals prop
handle TERM _ =>
raise THM("abstract_rule: premise not an equality", 0, [th])
- fun result T =
- Thm{sign_ref = sign_ref,
+ fun result T = fix_shyps [th] []
+ (Thm{sign_ref = sign_ref,
der = infer_derivs (Abstract_rule (a,cx), [der]),
maxidx = maxidx,
- shyps = add_typ_sorts (T, shyps),
+ shyps = [],
hyps = hyps,
prop = Logic.mk_equals(Abs(a, T, abstract_over (x,t)),
- Abs(a, T, abstract_over (x,u)))}
+ Abs(a, T, abstract_over (x,u)))})
in case x of
Free(_,T) =>
if exists (apl(x, Logic.occs)) hyps
@@ -948,18 +922,17 @@
prop=prop1,...} = th1
and Thm{der=der2, maxidx=max2, shyps=shyps2, hyps=hyps2,
prop=prop2,...} = th2
- fun chktypes fT tT =
- (case fT of
+ fun chktypes (f,t) =
+ (case fastype_of f of
Type("fun",[T1,T2]) =>
- if T1 <> tT then
+ if T1 <> fastype_of t then
raise THM("combination: types", 0, [th1,th2])
else ()
| _ => raise THM("combination: not function type", 0,
[th1,th2]))
in case (prop1,prop2) of
- (Const ("==", Type ("fun", [fT, _])) $ f $ g,
- Const ("==", Type ("fun", [tT, _])) $ t $ u) =>
- let val _ = chktypes fT tT
+ (Const("==",_) $ f $ g, Const("==",_) $ t $ u) =>
+ let val _ = chktypes (f,t)
val thm = (*no fix_shyps*)
Thm{sign_ref = merge_thm_sgs(th1,th2),
der = infer_derivs (Combination, [der1, der2]),
@@ -1105,19 +1078,20 @@
Instantiates distinct Vars by terms of same type.
No longer normalizes the new theorem! *)
fun instantiate ([], []) th = th
- | instantiate (vcTs,ctpairs) (th as Thm{sign_ref,der,maxidx,hyps,shyps,prop}) =
+ | instantiate (vcTs,ctpairs) (th as Thm{sign_ref,der,maxidx,hyps,prop,...}) =
let val (newsign_ref,tpairs) = foldr add_ctpair (ctpairs, (sign_ref,[]));
val (newsign_ref,vTs) = foldr add_ctyp (vcTs, (newsign_ref,[]));
val newprop = subst_atomic tpairs
(Type.inst_term_tvars
(Sign.tsig_of (Sign.deref newsign_ref),vTs) prop)
val newth =
- (Thm{sign_ref = newsign_ref,
- der = infer_derivs (Instantiate(vcTs,ctpairs), [der]),
- maxidx = maxidx_of_term newprop,
- shyps = add_insts_sorts ((vTs, tpairs), shyps),
- hyps = hyps,
- prop = newprop})
+ fix_shyps [th] (map snd vTs)
+ (Thm{sign_ref = newsign_ref,
+ der = infer_derivs (Instantiate(vcTs,ctpairs), [der]),
+ maxidx = maxidx_of_term newprop,
+ shyps = [],
+ hyps = hyps,
+ prop = newprop})
in if not(instl_ok(map #1 tpairs))
then raise THM("instantiate: variables not distinct", 0, [th])
else if not(null(findrep(map #1 vTs)))
@@ -1223,16 +1197,6 @@
lift_all B)}
end;
-(*
-fun incr_indexes i (Thm {sign_ref, der, maxidx, shyps, hyps, prop}) =
- Thm {sign_ref = sign_ref,
- der = der,
- maxidx = maxidx + i,
- shyps = shyps,
- hyps = hyps,
- prop = Logic.incr_indexes ([], i) prop};
-*)
-
(*Solve subgoal Bi of proof state B1...Bn/C by assumption. *)
fun assumption i state =
let val Thm{sign_ref,der,maxidx,hyps,prop,...} = state;
@@ -1551,6 +1515,845 @@
in Seq.flat (res brules) end;
+
+(*** Meta Simplification ***)
+
+(** diagnostics **)
+
+exception SIMPLIFIER of string * thm;
+
+fun prnt warn a = if warn then warning a else writeln a;
+
+fun prtm warn a sign t =
+ (prnt warn a; prnt warn (Sign.string_of_term sign t));
+
+fun prthm warn a (thm as Thm{sign_ref, prop, ...}) =
+ (prtm warn a (Sign.deref sign_ref) prop);
+
+val trace_simp = ref false;
+val debug_simp = ref false;
+
+fun trace warn a = if !trace_simp then prnt warn a else ();
+fun debug warn a = if !debug_simp then prnt warn a else ();
+
+fun trace_term warn a sign t = if !trace_simp then prtm warn a sign t else ();
+fun debug_term warn a sign t = if !debug_simp then prtm warn a sign t else ();
+
+fun trace_thm warn a (thm as Thm{sign_ref, prop, ...}) =
+ (trace_term warn a (Sign.deref sign_ref) prop);
+
+
+
+(** meta simp sets **)
+
+(* basic components *)
+
+type rrule = {thm: thm, lhs: term, elhs: term, fo: bool, perm: bool};
+(* thm: the rewrite rule
+ lhs: the left-hand side
+ elhs: the etac-contracted lhs.
+ fo: use first-order matching
+ perm: the rewrite rule is permutative
+Reamrks:
+ - elhs is used for matching,
+ lhs only for preservation of bound variable names.
+ - fo is set iff
+ either elhs is first-order (no Var is applied),
+ in which case fo-matching is complete,
+ or elhs is not a pattern,
+ in which case there is nothing better to do.
+*)
+type cong = {thm: thm, lhs: term};
+type simproc =
+ {name: string, proc: Sign.sg -> thm list -> term -> thm option, lhs: cterm, id: stamp};
+
+fun eq_rrule ({thm = Thm {prop = p1, ...}, ...}: rrule,
+ {thm = Thm {prop = p2, ...}, ...}: rrule) = p1 aconv p2;
+
+fun eq_cong ({thm = Thm {prop = p1, ...}, ...}: cong,
+ {thm = Thm {prop = p2, ...}, ...}: cong) = p1 aconv p2;
+
+fun eq_prem (Thm {prop = p1, ...}, Thm {prop = p2, ...}) = p1 aconv p2;
+
+fun eq_simproc ({id = s1, ...}:simproc, {id = s2, ...}:simproc) = (s1 = s2);
+
+fun mk_simproc (name, proc, lhs, id) =
+ {name = name, proc = proc, lhs = lhs, id = id};
+
+
+(* datatype mss *)
+
+(*
+ A "mss" contains data needed during conversion:
+ rules: discrimination net of rewrite rules;
+ congs: association list of congruence rules and
+ a list of `weak' congruence constants.
+ A congruence is `weak' if it avoids normalization of some argument.
+ procs: discrimination net of simplification procedures
+ (functions that prove rewrite rules on the fly);
+ bounds: names of bound variables already used
+ (for generating new names when rewriting under lambda abstractions);
+ prems: current premises;
+ mk_rews: mk: turns simplification thms into rewrite rules;
+ mk_sym: turns == around; (needs Drule!)
+ mk_eq_True: turns P into P == True - logic specific;
+ termless: relation for ordered rewriting;
+*)
+
+datatype meta_simpset =
+ Mss of {
+ rules: rrule Net.net,
+ congs: (string * cong) list * string list,
+ procs: simproc Net.net,
+ bounds: string list,
+ prems: thm list,
+ mk_rews: {mk: thm -> thm list,
+ mk_sym: thm -> thm option,
+ mk_eq_True: thm -> thm option},
+ termless: term * term -> bool};
+
+fun mk_mss (rules, congs, procs, bounds, prems, mk_rews, termless) =
+ Mss {rules = rules, congs = congs, procs = procs, bounds = bounds,
+ prems=prems, mk_rews=mk_rews, termless=termless};
+
+fun upd_rules(Mss{rules,congs,procs,bounds,prems,mk_rews,termless}, rules') =
+ mk_mss(rules',congs,procs,bounds,prems,mk_rews,termless);
+
+val empty_mss =
+ let val mk_rews = {mk = K [], mk_sym = K None, mk_eq_True = K None}
+ in mk_mss (Net.empty, ([], []), Net.empty, [], [], mk_rews, Term.termless) end;
+
+fun clear_mss (Mss {mk_rews, termless, ...}) =
+ mk_mss (Net.empty, ([], []), Net.empty, [], [], mk_rews, termless);
+
+
+
+(** simpset operations **)
+
+(* term variables *)
+
+val add_term_varnames = foldl_aterms (fn (xs, Var (x, _)) => ins_ix (x, xs) | (xs, _) => xs);
+fun term_varnames t = add_term_varnames ([], t);
+
+
+(* dest_mss *)
+
+fun dest_mss (Mss {rules, congs, procs, ...}) =
+ {simps = map (fn (_, {thm, ...}) => thm) (Net.dest rules),
+ congs = map (fn (_, {thm, ...}) => thm) (fst congs),
+ procs =
+ map (fn (_, {name, lhs, id, ...}) => ((name, lhs), id)) (Net.dest procs)
+ |> partition_eq eq_snd
+ |> map (fn ps => (#1 (#1 (hd ps)), map (#2 o #1) ps))
+ |> Library.sort_wrt #1};
+
+
+(* merge_mss *) (*NOTE: ignores mk_rews and termless of 2nd mss*)
+
+fun merge_mss
+ (Mss {rules = rules1, congs = (congs1,weak1), procs = procs1,
+ bounds = bounds1, prems = prems1, mk_rews, termless},
+ Mss {rules = rules2, congs = (congs2,weak2), procs = procs2,
+ bounds = bounds2, prems = prems2, ...}) =
+ mk_mss
+ (Net.merge (rules1, rules2, eq_rrule),
+ (generic_merge (eq_cong o pairself snd) I I congs1 congs2,
+ merge_lists weak1 weak2),
+ Net.merge (procs1, procs2, eq_simproc),
+ merge_lists bounds1 bounds2,
+ generic_merge eq_prem I I prems1 prems2,
+ mk_rews, termless);
+
+
+(* add_simps *)
+
+fun mk_rrule2{thm,lhs,elhs,perm} =
+ let val fo = Pattern.first_order elhs orelse not(Pattern.pattern elhs)
+ in {thm=thm,lhs=lhs,elhs=elhs,fo=fo,perm=perm} end
+
+fun insert_rrule(mss as Mss {rules,...},
+ rrule as {thm,lhs,elhs,perm}) =
+ (trace_thm false "Adding rewrite rule:" thm;
+ let val rrule2 as {elhs,...} = mk_rrule2 rrule
+ val rules' = Net.insert_term ((elhs, rrule2), rules, eq_rrule)
+ in upd_rules(mss,rules') end
+ handle Net.INSERT =>
+ (prthm true "Ignoring duplicate rewrite rule:" thm; mss));
+
+fun vperm (Var _, Var _) = true
+ | vperm (Abs (_, _, s), Abs (_, _, t)) = vperm (s, t)
+ | vperm (t1 $ t2, u1 $ u2) = vperm (t1, u1) andalso vperm (t2, u2)
+ | vperm (t, u) = (t = u);
+
+fun var_perm (t, u) =
+ vperm (t, u) andalso eq_set (term_varnames t, term_varnames u);
+
+(* FIXME: it seems that the conditions on extra variables are too liberal if
+prems are nonempty: does solving the prems really guarantee instantiation of
+all its Vars? Better: a dynamic check each time a rule is applied.
+*)
+fun rewrite_rule_extra_vars prems elhs erhs =
+ not (term_varnames erhs subset foldl add_term_varnames (term_varnames elhs, prems))
+ orelse
+ not ((term_tvars erhs) subset
+ (term_tvars elhs union List.concat(map term_tvars prems)));
+
+(*Simple test for looping rewrite rules and stupid orientations*)
+fun reorient sign prems lhs rhs =
+ rewrite_rule_extra_vars prems lhs rhs
+ orelse
+ is_Var (head_of lhs)
+ orelse
+ (exists (apl (lhs, Logic.occs)) (rhs :: prems))
+ orelse
+ (null prems andalso
+ Pattern.matches (#tsig (Sign.rep_sg sign)) (lhs, rhs))
+ (*the condition "null prems" is necessary because conditional rewrites
+ with extra variables in the conditions may terminate although
+ the rhs is an instance of the lhs. Example: ?m < ?n ==> f(?n) == f(?m)*)
+ orelse
+ (is_Const lhs andalso not(is_Const rhs))
+
+fun decomp_simp(thm as Thm {sign_ref, prop, ...}) =
+ let val sign = Sign.deref sign_ref;
+ val prems = Logic.strip_imp_prems prop;
+ val concl = Logic.strip_imp_concl prop;
+ val (lhs, rhs) = Logic.dest_equals concl handle TERM _ =>
+ raise SIMPLIFIER ("Rewrite rule not a meta-equality", thm)
+ val elhs = Pattern.eta_contract lhs;
+ val elhs = if elhs=lhs then lhs else elhs (* try to share *)
+ val erhs = Pattern.eta_contract rhs;
+ val perm = var_perm (elhs, erhs) andalso not (elhs aconv erhs)
+ andalso not (is_Var elhs)
+ in (sign,prems,lhs,elhs,rhs,perm) end;
+
+fun mk_eq_True (Mss{mk_rews={mk_eq_True,...},...}) thm =
+ case mk_eq_True thm of
+ None => []
+ | Some eq_True => let val (_,_,lhs,elhs,_,_) = decomp_simp eq_True
+ in [{thm=eq_True, lhs=lhs, elhs=elhs, perm=false}] end;
+
+(* create the rewrite rule and possibly also the ==True variant,
+ in case there are extra vars on the rhs *)
+fun rrule_eq_True(thm,lhs,elhs,rhs,mss,thm2) =
+ let val rrule = {thm=thm, lhs=lhs, elhs=elhs, perm=false}
+ in if (term_varnames rhs) subset (term_varnames lhs) andalso
+ (term_tvars rhs) subset (term_tvars lhs)
+ then [rrule]
+ else mk_eq_True mss thm2 @ [rrule]
+ end;
+
+fun mk_rrule mss thm =
+ let val (_,prems,lhs,elhs,rhs,perm) = decomp_simp thm
+ in if perm then [{thm=thm, lhs=lhs, elhs=elhs, perm=true}] else
+ (* weak test for loops: *)
+ if rewrite_rule_extra_vars prems lhs rhs orelse
+ is_Var elhs
+ then mk_eq_True mss thm
+ else rrule_eq_True(thm,lhs,elhs,rhs,mss,thm)
+ end;
+
+fun orient_rrule mss thm =
+ let val (sign,prems,lhs,elhs,rhs,perm) = decomp_simp thm
+ in if perm then [{thm=thm,lhs=lhs,elhs=elhs,perm=true}]
+ else if reorient sign prems lhs rhs
+ then if reorient sign prems rhs lhs
+ then mk_eq_True mss thm
+ else let val Mss{mk_rews={mk_sym,...},...} = mss
+ in case mk_sym thm of
+ None => []
+ | Some thm' =>
+ let val (_,_,lhs',elhs',rhs',_) = decomp_simp thm'
+ in rrule_eq_True(thm',lhs',elhs',rhs',mss,thm) end
+ end
+ else rrule_eq_True(thm,lhs,elhs,rhs,mss,thm)
+ end;
+
+fun extract_rews(Mss{mk_rews = {mk,...},...},thms) = flat(map mk thms);
+
+fun orient_comb_simps comb mk_rrule (mss,thms) =
+ let val rews = extract_rews(mss,thms)
+ val rrules = flat (map mk_rrule rews)
+ in foldl comb (mss,rrules) end
+
+(* Add rewrite rules explicitly; do not reorient! *)
+fun add_simps(mss,thms) =
+ orient_comb_simps insert_rrule (mk_rrule mss) (mss,thms);
+
+fun mss_of thms =
+ foldl insert_rrule (empty_mss, flat(map (mk_rrule empty_mss) thms));
+
+fun extract_safe_rrules(mss,thm) =
+ flat (map (orient_rrule mss) (extract_rews(mss,[thm])));
+
+fun add_safe_simp(mss,thm) =
+ foldl insert_rrule (mss, extract_safe_rrules(mss,thm))
+
+(* del_simps *)
+
+fun del_rrule(mss as Mss {rules,...},
+ rrule as {thm, elhs, ...}) =
+ (upd_rules(mss, Net.delete_term ((elhs, rrule), rules, eq_rrule))
+ handle Net.DELETE =>
+ (prthm true "Rewrite rule not in simpset:" thm; mss));
+
+fun del_simps(mss,thms) =
+ orient_comb_simps del_rrule (map mk_rrule2 o mk_rrule mss) (mss,thms);
+
+
+(* add_congs *)
+
+fun is_full_cong_prems [] varpairs = null varpairs
+ | is_full_cong_prems (p::prems) varpairs =
+ (case Logic.strip_assums_concl p of
+ Const("==",_) $ lhs $ rhs =>
+ let val (x,xs) = strip_comb lhs and (y,ys) = strip_comb rhs
+ in is_Var x andalso forall is_Bound xs andalso
+ null(findrep(xs)) andalso xs=ys andalso
+ (x,y) mem varpairs andalso
+ is_full_cong_prems prems (varpairs\(x,y))
+ end
+ | _ => false);
+
+fun is_full_cong (Thm{prop,...}) =
+let val prems = Logic.strip_imp_prems prop
+ and concl = Logic.strip_imp_concl prop
+ val (lhs,rhs) = Logic.dest_equals concl
+ val (f,xs) = strip_comb lhs
+ and (g,ys) = strip_comb rhs
+in
+ f=g andalso null(findrep(xs@ys)) andalso length xs = length ys andalso
+ is_full_cong_prems prems (xs ~~ ys)
+end
+
+fun add_cong (Mss {rules,congs,procs,bounds,prems,mk_rews,termless}, thm) =
+ let
+ val (lhs, _) = Logic.dest_equals (concl_of thm) handle TERM _ =>
+ raise SIMPLIFIER ("Congruence not a meta-equality", thm);
+(* val lhs = Pattern.eta_contract lhs; *)
+ val (a, _) = dest_Const (head_of lhs) handle TERM _ =>
+ raise SIMPLIFIER ("Congruence must start with a constant", thm);
+ val (alist,weak) = congs
+ val alist2 = overwrite_warn (alist, (a,{lhs=lhs, thm=thm}))
+ ("Overwriting congruence rule for " ^ quote a);
+ val weak2 = if is_full_cong thm then weak else a::weak
+ in
+ mk_mss (rules, (alist2,weak2), procs, bounds, prems, mk_rews, termless)
+ end;
+
+val (op add_congs) = foldl add_cong;
+
+
+(* del_congs *)
+
+fun del_cong (Mss {rules,congs,procs,bounds,prems,mk_rews,termless}, thm) =
+ let
+ val (lhs, _) = Logic.dest_equals (concl_of thm) handle TERM _ =>
+ raise SIMPLIFIER ("Congruence not a meta-equality", thm);
+(* val lhs = Pattern.eta_contract lhs; *)
+ val (a, _) = dest_Const (head_of lhs) handle TERM _ =>
+ raise SIMPLIFIER ("Congruence must start with a constant", thm);
+ val (alist,_) = congs
+ val alist2 = filter (fn (x,_)=> x<>a) alist
+ val weak2 = mapfilter (fn(a,{thm,...}) => if is_full_cong thm then None
+ else Some a)
+ alist2
+ in
+ mk_mss (rules, (alist2,weak2), procs, bounds, prems, mk_rews, termless)
+ end;
+
+val (op del_congs) = foldl del_cong;
+
+
+(* add_simprocs *)
+
+fun add_proc (mss as Mss {rules,congs,procs,bounds,prems,mk_rews,termless},
+ (name, lhs as Cterm {sign_ref, t, ...}, proc, id)) =
+ (trace_term false ("Adding simplification procedure " ^ quote name ^ " for")
+ (Sign.deref sign_ref) t;
+ mk_mss (rules, congs,
+ Net.insert_term ((t, mk_simproc (name, proc, lhs, id)), procs, eq_simproc)
+ handle Net.INSERT =>
+ (warning ("Ignoring duplicate simplification procedure \""
+ ^ name ^ "\"");
+ procs),
+ bounds, prems, mk_rews, termless));
+
+fun add_simproc (mss, (name, lhss, proc, id)) =
+ foldl add_proc (mss, map (fn lhs => (name, lhs, proc, id)) lhss);
+
+val add_simprocs = foldl add_simproc;
+
+
+(* del_simprocs *)
+
+fun del_proc (mss as Mss {rules,congs,procs,bounds,prems,mk_rews,termless},
+ (name, lhs as Cterm {t, ...}, proc, id)) =
+ mk_mss (rules, congs,
+ Net.delete_term ((t, mk_simproc (name, proc, lhs, id)), procs, eq_simproc)
+ handle Net.DELETE =>
+ (warning ("Simplification procedure \"" ^ name ^
+ "\" not in simpset"); procs),
+ bounds, prems, mk_rews, termless);
+
+fun del_simproc (mss, (name, lhss, proc, id)) =
+ foldl del_proc (mss, map (fn lhs => (name, lhs, proc, id)) lhss);
+
+val del_simprocs = foldl del_simproc;
+
+
+(* prems *)
+
+fun add_prems (Mss {rules,congs,procs,bounds,prems,mk_rews,termless}, thms) =
+ mk_mss (rules, congs, procs, bounds, thms @ prems, mk_rews, termless);
+
+fun prems_of_mss (Mss {prems, ...}) = prems;
+
+
+(* mk_rews *)
+
+fun set_mk_rews
+ (Mss {rules, congs, procs, bounds, prems, mk_rews, termless}, mk) =
+ mk_mss (rules, congs, procs, bounds, prems,
+ {mk=mk, mk_sym= #mk_sym mk_rews, mk_eq_True= #mk_eq_True mk_rews},
+ termless);
+
+fun set_mk_sym
+ (Mss {rules, congs, procs, bounds, prems, mk_rews, termless}, mk_sym) =
+ mk_mss (rules, congs, procs, bounds, prems,
+ {mk= #mk mk_rews, mk_sym= mk_sym, mk_eq_True= #mk_eq_True mk_rews},
+ termless);
+
+fun set_mk_eq_True
+ (Mss {rules, congs, procs, bounds, prems, mk_rews, termless}, mk_eq_True) =
+ mk_mss (rules, congs, procs, bounds, prems,
+ {mk= #mk mk_rews, mk_sym= #mk_sym mk_rews, mk_eq_True= mk_eq_True},
+ termless);
+
+(* termless *)
+
+fun set_termless
+ (Mss {rules, congs, procs, bounds, prems, mk_rews, termless = _}, termless) =
+ mk_mss (rules, congs, procs, bounds, prems, mk_rews, termless);
+
+
+
+(** rewriting **)
+
+(*
+ Uses conversions, omitting proofs for efficiency. See:
+ L C Paulson, A higher-order implementation of rewriting,
+ Science of Computer Programming 3 (1983), pages 119-149.
+*)
+
+type prover = meta_simpset -> thm -> thm option;
+type termrec = (Sign.sg_ref * term list) * term;
+type conv = meta_simpset -> termrec -> termrec;
+
+fun check_conv
+ (thm as Thm{shyps,hyps,prop,sign_ref,der,...}, prop0, ders) =
+ let fun err() = (trace_thm false "Proved wrong thm (Check subgoaler?)" thm;
+ trace_term false "Should have proved:" (Sign.deref sign_ref) prop0;
+ None)
+ val (lhs0,_) = Logic.dest_equals(Logic.strip_imp_concl prop0)
+ in case prop of
+ Const("==",_) $ lhs $ rhs =>
+ if (lhs = lhs0) orelse
+ (lhs aconv Envir.norm_term (Envir.empty 0) lhs0)
+ then (trace_thm false "SUCCEEDED" thm;
+ Some(rhs, (shyps, hyps, der::ders)))
+ else err()
+ | _ => err()
+ end;
+
+fun ren_inst(insts,prop,pat,obj) =
+ let val ren = match_bvs(pat,obj,[])
+ fun renAbs(Abs(x,T,b)) =
+ Abs(if_none(assoc_string(ren,x)) x, T, renAbs(b))
+ | renAbs(f$t) = renAbs(f) $ renAbs(t)
+ | renAbs(t) = t
+ in subst_vars insts (if null(ren) then prop else renAbs(prop)) end;
+
+fun incr_insts i (in1:(indexname*typ)list,in2:(indexname*term)list) =
+ let fun incr ((a,n),x) = ((a,n+i),x)
+ in (map incr in1, map incr in2) end;
+
+fun add_insts_sorts ((iTs, is), Ss) =
+ add_typs_sorts (map snd iTs, add_terms_sorts (map snd is, Ss));
+
+
+(* mk_procrule *)
+
+fun mk_procrule thm =
+ let val (_,prems,lhs,elhs,rhs,_) = decomp_simp thm
+ in if rewrite_rule_extra_vars prems lhs rhs
+ then (prthm true "Extra vars on rhs:" thm; [])
+ else [mk_rrule2{thm=thm, lhs=lhs, elhs=elhs, perm=false}]
+ end;
+
+
+(* conversion to apply the meta simpset to a term *)
+
+(* Since the rewriting strategy is bottom-up, we avoid re-normalizing already
+ normalized terms by carrying around the rhs of the rewrite rule just
+ applied. This is called the `skeleton'. It is decomposed in parallel
+ with the term. Once a Var is encountered, the corresponding term is
+ already in normal form.
+ skel0 is a dummy skeleton that is to enforce complete normalization.
+*)
+val skel0 = Bound 0;
+
+(* Use rhs as skeleton only if the lhs does not contain unnormalized bits.
+ The latter may happen iff there are weak congruence rules for constants
+ in the lhs.
+*)
+fun uncond_skel((_,weak),(lhs,rhs)) =
+ if null weak then rhs (* optimization *)
+ else if exists_Const (fn (c,_) => c mem weak) lhs then skel0
+ else rhs;
+
+(* Behaves like unconditional rule if rhs does not contain vars not in the lhs.
+ Otherwise those vars may become instantiated with unnormalized terms
+ while the premises are solved.
+*)
+fun cond_skel(args as (congs,(lhs,rhs))) =
+ if term_varnames rhs subset term_varnames lhs then uncond_skel(args)
+ else skel0;
+
+(*
+ we try in order:
+ (1) beta reduction
+ (2) unconditional rewrite rules
+ (3) conditional rewrite rules
+ (4) simplification procedures
+
+ IMPORTANT: rewrite rules must not introduce new Vars or TVars!
+
+*)
+
+fun rewritec (prover,sign_reft,maxt)
+ (mss as Mss{rules, procs, termless, prems, congs, ...})
+ (t:term,etc as (shypst,hypst,ders)) =
+ let
+ val eta_t = Pattern.eta_contract t;
+ val signt = Sign.deref sign_reft;
+ val tsigt = Sign.tsig_of signt;
+ fun rew{thm as Thm{sign_ref,der,shyps,hyps,prop,maxidx,...},
+ lhs, elhs, fo, perm} =
+ let
+ val _ = if Sign.subsig (Sign.deref sign_ref, signt) then ()
+ else (prthm true "Ignoring rewrite rule from different theory:" thm;
+ raise Pattern.MATCH);
+ val rprop = if maxt = ~1 then prop
+ else Logic.incr_indexes([],maxt+1) prop;
+ val insts = if fo then Pattern.first_order_match tsigt (elhs,eta_t)
+ else Pattern.match tsigt (elhs,eta_t);
+ val insts = if maxt = ~1 then insts else incr_insts (maxt+1) insts
+ val prop' = ren_inst(insts,rprop,lhs,eta_t);
+ val hyps' = union_term(hyps,hypst);
+ val shyps' = add_insts_sorts (insts, union_sort(shyps,shypst));
+ val unconditional = (Logic.count_prems(prop',0) = 0);
+ val maxidx' = if unconditional then maxt else maxidx+maxt+1
+ val ct' = Cterm{sign_ref = sign_reft, (*used for deriv only*)
+ t = prop', T = propT, maxidx = maxidx'}
+ val der' = infer_derivs (RewriteC ct', [der]);
+ val thm' = Thm{sign_ref = sign_reft, der = der', shyps = shyps',
+ hyps = hyps', prop = prop', maxidx = maxidx'}
+ val (lhs',rhs') = Logic.dest_equals(Logic.strip_imp_concl prop')
+ in
+ if perm andalso not(termless(rhs',lhs')) then None
+ else
+ (trace_thm false "Applying instance of rewrite rule:" thm;
+ if unconditional
+ then
+ (trace_thm false "Rewriting:" thm';
+ let val lr = Logic.dest_equals prop
+ val trec' = (rhs', (shyps', hyps', der'::ders))
+ in Some(trec',uncond_skel(congs,lr)) end)
+ else
+ (trace_thm false "Trying to rewrite:" thm';
+ case prover mss thm' of
+ None => (trace_thm false "FAILED" thm'; None)
+ | Some(thm2) =>
+ (case check_conv(thm2,prop',ders) of
+ None => None |
+ Some trec =>
+ let val concl = Logic.strip_imp_concl prop
+ val lr = Logic.dest_equals concl
+ in Some(trec,cond_skel(congs,lr)) end)))
+ end
+
+ fun rews [] = None
+ | rews (rrule :: rrules) =
+ let val opt = rew rrule handle Pattern.MATCH => None
+ in case opt of None => rews rrules | some => some end;
+
+ fun sort_rrules rrs = let
+ fun is_simple({thm as Thm{prop,...}, ...}:rrule) = case prop of
+ Const("==",_) $ _ $ _ => true
+ | _ => false
+ fun sort [] (re1,re2) = re1 @ re2
+ | sort (rr::rrs) (re1,re2) = if is_simple rr
+ then sort rrs (rr::re1,re2)
+ else sort rrs (re1,rr::re2)
+ in sort rrs ([],[]) end
+
+ fun proc_rews ([]:simproc list) = None
+ | proc_rews ({name, proc, lhs = Cterm {t = plhs, ...}, ...} :: ps) =
+ if Pattern.matches tsigt (plhs, t) then
+ (debug_term false ("Trying procedure " ^ quote name ^ " on:") signt eta_t;
+ case proc signt prems eta_t of
+ None => (debug false "FAILED"; proc_rews ps)
+ | Some raw_thm =>
+ (trace_thm false ("Procedure " ^ quote name ^ " produced rewrite rule:") raw_thm;
+ (case rews (mk_procrule raw_thm) of
+ None => (trace false "IGNORED"; proc_rews ps)
+ | some => some)))
+ else proc_rews ps;
+ in case eta_t of
+ Abs (_, _, body) $ u => Some ((subst_bound (u, body), etc),skel0)
+ | _ => (case rews (sort_rrules (Net.match_term rules eta_t)) of
+ None => proc_rews (Net.match_term procs eta_t)
+ | some => some)
+ end;
+
+
+(* conversion to apply a congruence rule to a term *)
+
+fun congc (prover,sign_reft,maxt) {thm=cong,lhs=lhs} (t,(shypst,hypst,ders)) =
+ let val signt = Sign.deref sign_reft;
+ val tsig = Sign.tsig_of signt;
+ val Thm{sign_ref,der,shyps,hyps,maxidx,prop,...} = cong
+ val _ = if Sign.subsig(Sign.deref sign_ref,signt) then ()
+ else error("Congruence rule from different theory")
+ val rprop = if maxt = ~1 then prop
+ else Logic.incr_indexes([],maxt+1) prop;
+ val rlhs = if maxt = ~1 then lhs
+ else fst(Logic.dest_equals(Logic.strip_imp_concl rprop))
+ val insts = Pattern.match tsig (rlhs,t)
+ (* Pattern.match can raise Pattern.MATCH;
+ is handled when congc is called *)
+ val prop' = ren_inst(insts,rprop,rlhs,t);
+ val shyps' = add_insts_sorts (insts, union_sort(shyps,shypst))
+ val maxidx' = maxidx_of_term prop'
+ val ct' = Cterm{sign_ref = sign_reft, (*used for deriv only*)
+ t = prop',
+ T = propT,
+ maxidx = maxidx'}
+ val thm' = Thm{sign_ref = sign_reft,
+ der = infer_derivs (CongC ct', [der]),
+ shyps = shyps',
+ hyps = union_term(hyps,hypst),
+ prop = prop',
+ maxidx = maxidx'};
+ val unit = trace_thm false "Applying congruence rule:" thm';
+ fun err(msg,thm) = (prthm false msg thm; error("Failed congruence proof!"))
+
+ in case prover thm' of
+ None => err("Could not prove",thm')
+ | Some(thm2) => (case check_conv(thm2,prop',ders) of
+ None => err("Should not have proved",thm2) | Some trec => trec)
+ end;
+
+fun bottomc ((simprem,useprem,mutsimp),prover,sign_ref,maxidx) =
+ let
+ fun botc fail skel mss trec =
+ if is_Var skel then if fail then None else Some(trec)
+ else
+ (case subc skel mss trec of
+ some as Some(trec1) =>
+ (case rewritec (prover,sign_ref,maxidx) mss trec1 of
+ Some(trec2,skel2) => botc false skel2 mss trec2
+ | None => some)
+ | None =>
+ (case rewritec (prover,sign_ref,maxidx) mss trec of
+ Some(trec2,skel2) => botc false skel2 mss trec2
+ | None => if fail then None else Some(trec)))
+
+ and try_botc mss trec =
+ (case botc true skel0 mss trec of
+ Some(trec1) => trec1 | None => trec)
+
+ and subc skel
+ (mss as Mss{rules,congs,procs,bounds,prems,mk_rews,termless})
+ (trec as (t0:term,etc:sort list*term list * (bool * deriv) list)) =
+ (case t0 of
+ Abs(a,T,t) =>
+ let val b = variant bounds a
+ val v = Free("." ^ b,T)
+ val mss' = mk_mss (rules, congs, procs, b :: bounds, prems, mk_rews, termless)
+ val skel' = case skel of Abs(_,_,sk) => sk | _ => skel0
+ in case botc true skel' mss' (subst_bound(v,t),etc) of
+ Some(t',etc') => Some(Abs(a, T, abstract_over(v,t')), etc')
+ | None => None
+ end
+ | t$u => (case t of
+ Const("==>",_)$s => Some(impc(s,u,mss,etc))
+ | Abs(_,_,body) =>
+ let val trec = (subst_bound(u,body), etc)
+ in case subc skel0 mss trec of
+ None => Some(trec)
+ | trec => trec
+ end
+ | _ =>
+ let fun appc() =
+ let val (tskel,uskel) =
+ case skel of tskel$uskel => (tskel,uskel)
+ | _ => (skel0,skel0)
+ in
+ (case botc true tskel mss (t,etc) of
+ Some(t1,etc1) =>
+ (case botc true uskel mss (u,etc1) of
+ Some(u1,etc2) => Some(t1$u1, etc2)
+ | None => Some(t1$u, etc1))
+ | None =>
+ (case botc true uskel mss (u,etc) of
+ Some(u1,etc1) => Some(t$u1, etc1)
+ | None => None))
+ end
+ val (h,ts) = strip_comb t
+ in case h of
+ Const(a,_) =>
+ (case assoc_string(fst congs,a) of
+ None => appc()
+ | Some(cong) =>
+(* post processing: some partial applications h t1 ... tj, j <= length ts,
+ may be a redex. Example: map (%x.x) = (%xs.xs) wrt map_cong *)
+ (let val ctrec as (t,etc) =
+ congc (prover mss,sign_ref,maxidx) cong trec
+ in case t of
+ l$r =>
+ let val dVar = Var(("",0),dummyT)
+ val skel =
+ list_comb(h,replicate (length ts) dVar)
+ in case botc true skel mss (l,etc) of
+ None => Some ctrec
+ | Some(l',etc') => Some(l'$r,etc')
+ end
+ | _ => error "congc result"
+ end
+ handle Pattern.MATCH => appc() ) )
+ | _ => appc()
+ end)
+ | _ => None)
+
+ and impc args =
+ if mutsimp
+ then let val (prem, conc, mss, etc) = args
+ in snd(mut_impc([], prem, conc, mss, etc)) end
+ else nonmut_impc args
+
+ and mut_impc (prems, prem, conc, mss, etc) =
+ let val (prem1,etc1) = try_botc mss (prem,etc)
+ in mut_impc1(prems, prem1, conc, mss, etc1) end
+
+ and mut_impc1(prems, prem1, conc, mss, etc1 as (_,hyps1,_)) =
+ let
+ fun uncond({thm,lhs,elhs,perm}) =
+ if no_prems thm then Some lhs else None
+
+ val (lhss1,mss1) =
+ if maxidx_of_term prem1 <> ~1
+ then (trace_term true "Cannot add premise as rewrite rule because it contains (type) unknowns:"
+ (Sign.deref sign_ref) prem1;
+ ([],mss))
+ else let val thm = assume (Cterm{sign_ref=sign_ref, t=prem1,
+ T=propT, maxidx= ~1})
+ val rrules1 = extract_safe_rrules(mss,thm)
+ val lhss1 = mapfilter uncond rrules1
+ val mss1 = foldl insert_rrule (add_prems(mss,[thm]),rrules1)
+ in (lhss1, mss1) end
+
+ fun disch1(conc2,(shyps2,hyps2,ders2)) =
+ let val hyps2' = if gen_mem (op aconv) (prem1, hyps1)
+ then hyps2 else hyps2\prem1
+ in (Logic.mk_implies(prem1,conc2),(shyps2,hyps2',ders2)) end
+
+ fun rebuild trec2 =
+ let val trec = disch1 trec2
+ in case rewritec (prover,sign_ref,maxidx) mss trec of
+ None => (None,trec)
+ | Some((Const("==>",_)$prem$conc,etc),_) =>
+ mut_impc(prems,prem,conc,mss,etc)
+ | Some(trec',_) => (None,trec')
+ end
+
+ fun simpconc() =
+ case conc of
+ Const("==>",_)$s$t =>
+ (case mut_impc(prems@[prem1],s,t,mss1,etc1) of
+ (Some(i,prem),trec2) =>
+ let val trec2' = disch1 trec2
+ in if i=0 then mut_impc1(prems,prem,fst trec2',mss,snd trec2')
+ else (Some(i-1,prem),trec2')
+ end
+ | (None,trec) => rebuild(trec))
+ | _ => rebuild(try_botc mss1 (conc,etc1))
+
+ in let val sg = Sign.deref sign_ref
+ val tsig = #tsig(Sign.rep_sg sg)
+ fun reducible t =
+ exists (fn lhs => Pattern.matches_subterm tsig (lhs,t))
+ lhss1;
+ in case dropwhile (not o reducible) prems of
+ [] => simpconc()
+ | red::rest => (trace_term false "Can now reduce premise:" sg
+ red;
+ (Some(length rest,prem1),(conc,etc1)))
+ end
+ end
+
+ (* legacy code - only for backwards compatibility *)
+ and nonmut_impc(prem, conc, mss, etc as (_,hyps1,_)) =
+ let val (prem1,etc1) = if simprem then try_botc mss (prem,etc)
+ else (prem,etc)
+ val maxidx1 = maxidx_of_term prem1
+ val mss1 =
+ if not useprem then mss else
+ if maxidx1 <> ~1
+ then (trace_term true "Cannot add premise as rewrite rule because it contains (type) unknowns:"
+ (Sign.deref sign_ref) prem1;
+ mss)
+ else let val thm = assume (Cterm{sign_ref=sign_ref, t=prem1,
+ T=propT, maxidx= ~1})
+ in add_safe_simp(add_prems(mss,[thm]), thm) end
+ val (conc2,(shyps2,hyps2,ders2)) = try_botc mss1 (conc,etc1)
+ val hyps2' = if prem1 mem hyps1 then hyps2 else hyps2\prem1
+ in (Logic.mk_implies(prem1,conc2), (shyps2, hyps2', ders2)) end
+
+ in try_botc end;
+
+
+(*** Meta-rewriting: rewrites t to u and returns the theorem t==u ***)
+
+(*
+ Parameters:
+ mode = (simplify A,
+ use A in simplifying B,
+ use prems of B (if B is again a meta-impl.) to simplify A)
+ when simplifying A ==> B
+ mss: contains equality theorems of the form [|p1,...|] ==> t==u
+ prover: how to solve premises in conditional rewrites and congruences
+*)
+
+(* FIXME: check that #bounds(mss) does not "occur" in ct alread *)
+
+fun rewrite_cterm mode mss prover ct =
+ let val Cterm {sign_ref, t, T, maxidx} = ct;
+ val (u,(shyps,hyps,ders)) = bottomc (mode,prover, sign_ref, maxidx) mss
+ (t, (add_term_sorts(t,[]), [], []));
+ val prop = Logic.mk_equals(t,u)
+ in
+ Thm{sign_ref = sign_ref,
+ der = infer_derivs (Rewrite_cterm ct, ders),
+ maxidx = maxidx,
+ shyps = shyps,
+ hyps = hyps,
+ prop = prop}
+ end;
+
+
+
(*** Oracles ***)
fun invoke_oracle thy raw_name =