--- a/src/Pure/thm.ML Fri Oct 27 15:11:49 2000 +0200
+++ b/src/Pure/thm.ML Fri Oct 27 15:23:39 2000 +0200
@@ -28,10 +28,15 @@
val read_cterm : Sign.sg -> string * typ -> cterm
val cterm_fun : (term -> term) -> (cterm -> cterm)
val dest_comb : cterm -> cterm * cterm
- val dest_abs : cterm -> cterm * cterm
+ val dest_abs : string option -> 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
@@ -59,6 +64,7 @@
| Symmetric
| Transitive
| Beta_conversion of cterm
+ | Eta_conversion of cterm
| Extensional
| Abstract_rule of string * cterm
| Combination
@@ -117,7 +123,8 @@
val reflexive : cterm -> thm
val symmetric : thm -> thm
val transitive : thm -> thm -> thm
- val beta_conversion : cterm -> thm
+ val beta_conversion : bool -> cterm -> thm
+ val eta_conversion : cterm -> thm
val extensional : thm -> thm
val abstract_rule : string -> cterm -> thm -> thm
val combination : thm -> thm -> thm
@@ -135,6 +142,7 @@
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
@@ -144,37 +152,6 @@
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;
@@ -191,6 +168,11 @@
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 =
@@ -258,12 +240,12 @@
| dest_comb _ = raise CTERM "dest_comb";
(*Destruct abstraction in cterms*)
-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)
+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)
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, ...}) =
@@ -285,6 +267,33 @@
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*)
@@ -331,6 +340,7 @@
| Symmetric
| Transitive
| Beta_conversion of cterm
+ | Eta_conversion of cterm
| Extensional
| Abstract_rule of string * cterm
| Combination
@@ -528,6 +538,9 @@
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));
@@ -694,17 +707,17 @@
-------
A ==> B
*)
-fun implies_intr cA (thB as Thm{sign_ref,der,maxidx,hyps,prop,...}) : thm =
+fun implies_intr cA (thB as Thm{sign_ref,der,maxidx,hyps,shyps,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 fix_shyps [thB] []
- (Thm{sign_ref = Sign.merge_refs (sign_ref,sign_refA),
+ else
+ Thm{sign_ref = Sign.merge_refs (sign_ref,sign_refA),
der = infer_derivs (Implies_intr cA, [der]),
maxidx = Int.max(maxidxA, maxidx),
- shyps = [],
+ shyps = add_term_sorts (A, shyps),
hyps = disch(hyps,A),
- prop = implies$A$prop})
+ prop = implies$A$prop}
handle TERM _ =>
raise THM("implies_intr: incompatible signatures", 0, [thB])
end;
@@ -716,19 +729,19 @@
B
*)
fun implies_elim thAB thA : thm =
- let val Thm{maxidx=maxA, der=derA, hyps=hypsA, prop=propA,...} = thA
- and Thm{sign_ref, der, maxidx, hyps, prop,...} = thAB;
+ let val Thm{maxidx=maxA, der=derA, hyps=hypsA, shyps=shypsA, prop=propA, ...} = thA
+ and Thm{der, maxidx, hyps, shyps, 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 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})
+ 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}
else err("major premise")
| _ => err("major premise")
end;
@@ -821,20 +834,19 @@
t1==t2
*)
fun transitive th1 th2 =
- let val Thm{der=der1, maxidx=max1, hyps=hyps1, prop=prop1,...} = th1
- and Thm{der=der2, maxidx=max2, hyps=hyps2, prop=prop2,...} = 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;
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 =
- fix_shyps [th1, th2] []
- (Thm{sign_ref= merge_thm_sgs(th1,th2),
+ Thm{sign_ref= merge_thm_sgs(th1,th2),
der = infer_derivs (Transitive, [der1, der2]),
maxidx = Int.max(max1,max2),
- shyps = [],
+ shyps = union_sort (shyps1, shyps2),
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!*)
@@ -842,18 +854,32 @@
| _ => err"premises"
end;
-(*Beta-conversion: maps (%x.t)(u) to the theorem (%x.t)(u) == t[u/x] *)
-fun beta_conversion ct =
+(*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 =
let val Cterm {sign_ref, t, T, maxidx} = ct
- 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, [])
+ 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)})
end;
(*The extensionality rule (proviso: x not free in f, g, or hypotheses)
@@ -890,19 +916,19 @@
------------
%x.t == %x.u
*)
-fun abstract_rule a cx (th as Thm{sign_ref,der,maxidx,hyps,prop,...}) =
+fun abstract_rule a cx (th as Thm{sign_ref,der,maxidx,hyps,shyps,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 = fix_shyps [th] []
- (Thm{sign_ref = sign_ref,
+ fun result T =
+ Thm{sign_ref = sign_ref,
der = infer_derivs (Abstract_rule (a,cx), [der]),
maxidx = maxidx,
- shyps = [],
+ shyps = add_typ_sorts (T, 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
@@ -922,17 +948,18 @@
prop=prop1,...} = th1
and Thm{der=der2, maxidx=max2, shyps=shyps2, hyps=hyps2,
prop=prop2,...} = th2
- fun chktypes (f,t) =
- (case fastype_of f of
+ fun chktypes fT tT =
+ (case fT of
Type("fun",[T1,T2]) =>
- if T1 <> fastype_of t then
+ if T1 <> tT then
raise THM("combination: types", 0, [th1,th2])
else ()
| _ => raise THM("combination: not function type", 0,
[th1,th2]))
in case (prop1,prop2) of
- (Const("==",_) $ f $ g, Const("==",_) $ t $ u) =>
- let val _ = chktypes (f,t)
+ (Const ("==", Type ("fun", [fT, _])) $ f $ g,
+ Const ("==", Type ("fun", [tT, _])) $ t $ u) =>
+ let val _ = chktypes fT tT
val thm = (*no fix_shyps*)
Thm{sign_ref = merge_thm_sgs(th1,th2),
der = infer_derivs (Combination, [der1, der2]),
@@ -1078,20 +1105,19 @@
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,prop,...}) =
+ | instantiate (vcTs,ctpairs) (th as Thm{sign_ref,der,maxidx,hyps,shyps,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 =
- 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})
+ (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})
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)))
@@ -1197,6 +1223,16 @@
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;
@@ -1515,845 +1551,6 @@
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 =