# HG changeset patch # User wenzelm # Date 972653019 -7200 # Node ID 4dce06387aeafe2b64d189a5bddbe83069d2b514 # Parent 487acfd5f2d2b4f4ce3cad116a6be11718bc684c *** empty log message *** diff -r 487acfd5f2d2 -r 4dce06387aea src/Pure/thm.ML --- 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 =