Completing the bug fix from the previous update: the result of unifying type
variables must be normalized WRT itself; otherwise instantiation is wrong
(* Title: Pure/drule.ML
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1993 University of Cambridge
Derived rules and other operations on theorems.
*)
infix 0 RS RSN RL RLN MRS MRL OF COMP INCR_COMP COMP_INCR;
signature BASIC_DRULE =
sig
val mk_implies: cterm * cterm -> cterm
val list_implies: cterm list * cterm -> cterm
val dest_implies: cterm -> cterm * cterm
val dest_equals: cterm -> cterm * cterm
val dest_equals_lhs: cterm -> cterm
val dest_equals_rhs: cterm -> cterm
val strip_imp_prems: cterm -> cterm list
val strip_imp_concl: cterm -> cterm
val cprems_of: thm -> cterm list
val cterm_fun: (term -> term) -> (cterm -> cterm)
val ctyp_fun: (typ -> typ) -> (ctyp -> ctyp)
val read_insts: theory -> (indexname -> typ option) * (indexname -> sort option) ->
(indexname -> typ option) * (indexname -> sort option) -> string list ->
(indexname * string) list -> (ctyp * ctyp) list * (cterm * cterm) list
val types_sorts: thm -> (indexname-> typ option) * (indexname-> sort option)
val forall_intr_list: cterm list -> thm -> thm
val forall_intr_frees: thm -> thm
val forall_intr_vars: thm -> thm
val forall_elim_list: cterm list -> thm -> thm
val forall_elim_var: int -> thm -> thm
val forall_elim_vars: int -> thm -> thm
val gen_all: thm -> thm
val lift_all: cterm -> thm -> thm
val freeze_thaw: thm -> thm * (thm -> thm)
val freeze_thaw_robust: thm -> thm * (int -> thm -> thm)
val implies_elim_list: thm -> thm list -> thm
val implies_intr_list: cterm list -> thm -> thm
val instantiate: (ctyp * ctyp) list * (cterm * cterm) list -> thm -> thm
val zero_var_indexes_list: thm list -> thm list
val zero_var_indexes: thm -> thm
val implies_intr_hyps: thm -> thm
val standard: thm -> thm
val standard': thm -> thm
val rotate_prems: int -> thm -> thm
val rearrange_prems: int list -> thm -> thm
val RSN: thm * (int * thm) -> thm
val RS: thm * thm -> thm
val RLN: thm list * (int * thm list) -> thm list
val RL: thm list * thm list -> thm list
val MRS: thm list * thm -> thm
val MRL: thm list list * thm list -> thm list
val OF: thm * thm list -> thm
val compose: thm * int * thm -> thm list
val COMP: thm * thm -> thm
val INCR_COMP: thm * thm -> thm
val COMP_INCR: thm * thm -> thm
val read_instantiate_sg: theory -> (string*string)list -> thm -> thm
val read_instantiate: (string*string)list -> thm -> thm
val cterm_instantiate: (cterm*cterm)list -> thm -> thm
val eq_thm_thy: thm * thm -> bool
val eq_thm_prop: thm * thm -> bool
val equiv_thm: thm * thm -> bool
val size_of_thm: thm -> int
val reflexive_thm: thm
val symmetric_thm: thm
val transitive_thm: thm
val symmetric_fun: thm -> thm
val extensional: thm -> thm
val equals_cong: thm
val imp_cong: thm
val swap_prems_eq: thm
val asm_rl: thm
val cut_rl: thm
val revcut_rl: thm
val thin_rl: thm
val triv_forall_equality: thm
val distinct_prems_rl: thm
val swap_prems_rl: thm
val equal_intr_rule: thm
val equal_elim_rule1: thm
val equal_elim_rule2: thm
val instantiate': ctyp option list -> cterm option list -> thm -> thm
end;
signature DRULE =
sig
include BASIC_DRULE
val generalize: string list * string list -> thm -> thm
val list_comb: cterm * cterm list -> cterm
val strip_comb: cterm -> cterm * cterm list
val strip_type: ctyp -> ctyp list * ctyp
val lhs_of: thm -> cterm
val rhs_of: thm -> cterm
val beta_conv: cterm -> cterm -> cterm
val plain_prop_of: thm -> term
val fold_terms: (term -> 'a -> 'a) -> thm -> 'a -> 'a
val add_used: thm -> string list -> string list
val flexflex_unique: thm -> thm
val close_derivation: thm -> thm
val store_thm: bstring -> thm -> thm
val store_standard_thm: bstring -> thm -> thm
val store_thm_open: bstring -> thm -> thm
val store_standard_thm_open: bstring -> thm -> thm
val compose_single: thm * int * thm -> thm
val add_rule: thm -> thm list -> thm list
val del_rule: thm -> thm list -> thm list
val merge_rules: thm list * thm list -> thm list
val imp_cong_rule: thm -> thm -> thm
val beta_eta_conversion: cterm -> thm
val eta_long_conversion: cterm -> thm
val eta_contraction_rule: thm -> thm
val forall_conv: int -> (cterm -> thm) -> cterm -> thm
val concl_conv: int -> (cterm -> thm) -> cterm -> thm
val prems_conv: int -> (int -> cterm -> thm) -> cterm -> thm
val goals_conv: (int -> bool) -> (cterm -> thm) -> cterm -> thm
val fconv_rule: (cterm -> thm) -> thm -> thm
val norm_hhf_eq: thm
val is_norm_hhf: term -> bool
val norm_hhf: theory -> term -> term
val norm_hhf_cterm: cterm -> cterm
val unvarify: thm -> thm
val protect: cterm -> cterm
val protectI: thm
val protectD: thm
val protect_cong: thm
val implies_intr_protected: cterm list -> thm -> thm
val termI: thm
val mk_term: cterm -> thm
val dest_term: thm -> cterm
val cterm_rule: (thm -> thm) -> cterm -> cterm
val term_rule: theory -> (thm -> thm) -> term -> term
val sort_triv: theory -> typ * sort -> thm list
val unconstrainTs: thm -> thm
val rename_bvars: (string * string) list -> thm -> thm
val rename_bvars': string option list -> thm -> thm
val incr_indexes: thm -> thm -> thm
val incr_indexes2: thm -> thm -> thm -> thm
val remdups_rl: thm
val multi_resolve: thm list -> thm -> thm Seq.seq
val multi_resolves: thm list -> thm list -> thm Seq.seq
val abs_def: thm -> thm
val read_instantiate_sg': theory -> (indexname * string) list -> thm -> thm
val read_instantiate': (indexname * string) list -> thm -> thm
end;
structure Drule: DRULE =
struct
(** some cterm->cterm operations: faster than calling cterm_of! **)
fun dest_implies ct =
(case Thm.term_of ct of
Const ("==>", _) $ _ $ _ => Thm.dest_binop ct
| _ => raise TERM ("dest_implies", [Thm.term_of ct]));
fun dest_equals ct =
(case Thm.term_of ct of
Const ("==", _) $ _ $ _ => Thm.dest_binop ct
| _ => raise TERM ("dest_equals", [Thm.term_of ct]));
fun dest_equals_lhs ct =
(case Thm.term_of ct of
Const ("==", _) $ _ $ _ => #1 (Thm.dest_binop ct)
| _ => raise TERM ("dest_equals_lhs", [Thm.term_of ct]));
fun dest_equals_rhs ct =
(case Thm.term_of ct of
Const ("==", _) $ _ $ _ => Thm.dest_arg ct
| _ => raise TERM ("dest_equals_rhs", [Thm.term_of ct]));
val lhs_of = dest_equals_lhs o Thm.cprop_of;
val rhs_of = dest_equals_rhs o Thm.cprop_of;
(* A1==>...An==>B goes to [A1,...,An], where B is not an implication *)
fun strip_imp_prems ct =
let val (cA, cB) = dest_implies ct
in cA :: strip_imp_prems cB end
handle TERM _ => [];
(* A1==>...An==>B goes to B, where B is not an implication *)
fun strip_imp_concl ct =
(case Thm.term_of ct of
Const ("==>", _) $ _ $ _ => strip_imp_concl (Thm.dest_arg ct)
| _ => ct);
(*The premises of a theorem, as a cterm list*)
val cprems_of = strip_imp_prems o cprop_of;
fun cterm_fun f ct =
let val {t, thy, ...} = Thm.rep_cterm ct
in Thm.cterm_of thy (f t) end;
fun ctyp_fun f cT =
let val {T, thy, ...} = Thm.rep_ctyp cT
in Thm.ctyp_of thy (f T) end;
val cert = cterm_of ProtoPure.thy;
val implies = cert Term.implies;
fun mk_implies (A, B) = Thm.capply (Thm.capply implies A) B;
(*cterm version of list_implies: [A1,...,An], B goes to [|A1;==>;An|]==>B *)
fun list_implies([], B) = B
| list_implies(A::AS, B) = mk_implies (A, list_implies(AS,B));
(*cterm version of list_comb: maps (f, [t1,...,tn]) to f(t1,...,tn) *)
fun list_comb (f, []) = f
| list_comb (f, t::ts) = list_comb (Thm.capply f t, ts);
(*cterm version of strip_comb: maps f(t1,...,tn) to (f, [t1,...,tn]) *)
fun strip_comb ct =
let
fun stripc (p as (ct, cts)) =
let val (ct1, ct2) = Thm.dest_comb ct
in stripc (ct1, ct2 :: cts) end handle CTERM _ => p
in stripc (ct, []) end;
(* cterm version of strip_type: maps [T1,...,Tn]--->T to ([T1,T2,...,Tn], T) *)
fun strip_type cT = (case Thm.typ_of cT of
Type ("fun", _) =>
let
val [cT1, cT2] = Thm.dest_ctyp cT;
val (cTs, cT') = strip_type cT2
in (cT1 :: cTs, cT') end
| _ => ([], cT));
(*Beta-conversion for cterms, where x is an abstraction. Simply returns the rhs
of the meta-equality returned by the beta_conversion rule.*)
fun beta_conv x y =
Thm.dest_arg (cprop_of (Thm.beta_conversion false (Thm.capply x y)));
fun plain_prop_of raw_thm =
let
val thm = Thm.strip_shyps raw_thm;
fun err msg = raise THM ("plain_prop_of: " ^ msg, 0, [thm]);
val {hyps, prop, tpairs, ...} = Thm.rep_thm thm;
in
if not (null hyps) then
err "theorem may not contain hypotheses"
else if not (null (Thm.extra_shyps thm)) then
err "theorem may not contain sort hypotheses"
else if not (null tpairs) then
err "theorem may not contain flex-flex pairs"
else prop
end;
fun fold_terms f th =
let val {tpairs, prop, hyps, ...} = Thm.rep_thm th
in fold (fn (t, u) => f t #> f u) tpairs #> f prop #> fold f hyps end;
(** reading of instantiations **)
fun absent ixn =
error("No such variable in term: " ^ Syntax.string_of_vname ixn);
fun inst_failure ixn =
error("Instantiation of " ^ Syntax.string_of_vname ixn ^ " fails");
fun read_insts thy (rtypes,rsorts) (types,sorts) used insts =
let
fun is_tv ((a, _), _) =
(case Symbol.explode a of "'" :: _ => true | _ => false);
val (tvs, vs) = List.partition is_tv insts;
fun sort_of ixn = case rsorts ixn of SOME S => S | NONE => absent ixn;
fun readT (ixn, st) =
let val S = sort_of ixn;
val T = Sign.read_typ (thy,sorts) st;
in if Sign.typ_instance thy (T, TVar(ixn,S)) then (ixn,T)
else inst_failure ixn
end
val tye = map readT tvs;
fun mkty(ixn,st) = (case rtypes ixn of
SOME T => (ixn,(st,typ_subst_TVars tye T))
| NONE => absent ixn);
val ixnsTs = map mkty vs;
val ixns = map fst ixnsTs
and sTs = map snd ixnsTs
val (cts,tye2) = read_def_cterms(thy,types,sorts) used false sTs;
fun mkcVar(ixn,T) =
let val U = typ_subst_TVars tye2 T
in cterm_of thy (Var(ixn,U)) end
val ixnTs = ListPair.zip(ixns, map snd sTs)
in (map (fn (ixn, T) => (ctyp_of thy (TVar (ixn, sort_of ixn)),
ctyp_of thy T)) (tye2 @ tye),
ListPair.zip(map mkcVar ixnTs,cts))
end;
(*** Find the type (sort) associated with a (T)Var or (T)Free in a term
Used for establishing default types (of variables) and sorts (of
type variables) when reading another term.
Index -1 indicates that a (T)Free rather than a (T)Var is wanted.
***)
fun types_sorts thm =
let
val vars = fold_terms Term.add_vars thm [];
val frees = fold_terms Term.add_frees thm [];
val tvars = fold_terms Term.add_tvars thm [];
val tfrees = fold_terms Term.add_tfrees thm [];
fun types (a, i) =
if i < 0 then AList.lookup (op =) frees a else AList.lookup (op =) vars (a, i);
fun sorts (a, i) =
if i < 0 then AList.lookup (op =) tfrees a else AList.lookup (op =) tvars (a, i);
in (types, sorts) end;
val add_used =
(fold_terms o fold_types o fold_atyps)
(fn TFree (a, _) => insert (op =) a
| TVar ((a, _), _) => insert (op =) a
| _ => I);
(** Standardization of rules **)
(* type classes and sorts *)
fun sort_triv thy (T, S) =
let
val certT = Thm.ctyp_of thy;
val cT = certT T;
fun class_triv c =
Thm.class_triv thy c
|> Thm.instantiate ([(certT (TVar (("'a", 0), [c])), cT)], []);
in map class_triv S end;
fun unconstrainTs th =
fold (Thm.unconstrainT o Thm.ctyp_of (Thm.theory_of_thm th) o TVar)
(fold_terms Term.add_tvars th []) th;
(*Generalization over a list of variables*)
val forall_intr_list = fold_rev forall_intr;
(*Generalization over all suitable Free variables*)
fun forall_intr_frees th =
let
val {prop, hyps, tpairs, thy,...} = rep_thm th;
val fixed = fold Term.add_frees (Thm.terms_of_tpairs tpairs @ hyps) [];
val frees = Term.fold_aterms (fn Free v =>
if member (op =) fixed v then I else insert (op =) v | _ => I) prop [];
in fold (forall_intr o cterm_of thy o Free) frees th end;
(*Generalization over Vars -- canonical order*)
fun forall_intr_vars th =
fold forall_intr
(map (Thm.cterm_of (Thm.theory_of_thm th) o Var) (fold_terms Term.add_vars th [])) th;
val forall_elim_var = PureThy.forall_elim_var;
val forall_elim_vars = PureThy.forall_elim_vars;
fun outer_params t =
let val vs = Term.strip_all_vars t
in Name.variant_list [] (map (Name.clean o #1) vs) ~~ map #2 vs end;
(*generalize outermost parameters*)
fun gen_all th =
let
val {thy, prop, maxidx, ...} = Thm.rep_thm th;
val cert = Thm.cterm_of thy;
fun elim (x, T) = Thm.forall_elim (cert (Var ((x, maxidx + 1), T)));
in fold elim (outer_params prop) th end;
(*lift vars wrt. outermost goal parameters
-- reverses the effect of gen_all modulo higher-order unification*)
fun lift_all goal th =
let
val thy = Theory.merge (Thm.theory_of_cterm goal, Thm.theory_of_thm th);
val cert = Thm.cterm_of thy;
val maxidx = Thm.maxidx_of th;
val ps = outer_params (Thm.term_of goal)
|> map (fn (x, T) => Var ((x, maxidx + 1), Logic.incr_tvar (maxidx + 1) T));
val Ts = map Term.fastype_of ps;
val inst = fold_terms Term.add_vars th [] |> map (fn (xi, T) =>
(cert (Var (xi, T)), cert (Term.list_comb (Var (xi, Ts ---> T), ps))));
in
th |> Thm.instantiate ([], inst)
|> fold_rev (Thm.forall_intr o cert) ps
end;
(*direct generalization*)
fun generalize names th = Thm.generalize names (Thm.maxidx_of th + 1) th;
(*specialization over a list of cterms*)
val forall_elim_list = fold forall_elim;
(*maps A1,...,An |- B to [| A1;...;An |] ==> B*)
val implies_intr_list = fold_rev implies_intr;
(*maps [| A1;...;An |] ==> B and [A1,...,An] to B*)
fun implies_elim_list impth ths = Library.foldl (uncurry implies_elim) (impth,ths);
(*Reset Var indexes to zero, renaming to preserve distinctness*)
fun zero_var_indexes_list [] = []
| zero_var_indexes_list ths =
let
val thy = Theory.merge_list (map Thm.theory_of_thm ths);
val certT = Thm.ctyp_of thy and cert = Thm.cterm_of thy;
val (instT, inst) = TermSubst.zero_var_indexes_inst (map Thm.full_prop_of ths);
val cinstT = map (fn (v, T) => (certT (TVar v), certT T)) instT;
val cinst = map (fn (v, t) => (cert (Var v), cert t)) inst;
in map (Thm.adjust_maxidx_thm ~1 o Thm.instantiate (cinstT, cinst)) ths end;
val zero_var_indexes = singleton zero_var_indexes_list;
(** Standard form of object-rule: no hypotheses, flexflex constraints,
Frees, or outer quantifiers; all generality expressed by Vars of index 0.**)
(*Discharge all hypotheses.*)
fun implies_intr_hyps th =
fold Thm.implies_intr (#hyps (Thm.crep_thm th)) th;
(*Squash a theorem's flexflex constraints provided it can be done uniquely.
This step can lose information.*)
fun flexflex_unique th =
if null (tpairs_of th) then th else
case Seq.chop 2 (flexflex_rule th) of
([th],_) => th
| ([],_) => raise THM("flexflex_unique: impossible constraints", 0, [th])
| _ => raise THM("flexflex_unique: multiple unifiers", 0, [th]);
fun close_derivation thm =
if Thm.get_name thm = "" then Thm.put_name "" thm
else thm;
(* legacy standard operations *)
val standard' =
implies_intr_hyps
#> forall_intr_frees
#> `Thm.maxidx_of
#-> (fn maxidx =>
forall_elim_vars (maxidx + 1)
#> Thm.strip_shyps
#> zero_var_indexes
#> Thm.varifyT
#> Thm.compress);
val standard =
flexflex_unique
#> standard'
#> close_derivation;
(*Convert all Vars in a theorem to Frees. Also return a function for
reversing that operation. DOES NOT WORK FOR TYPE VARIABLES.
Similar code in type/freeze_thaw*)
fun freeze_thaw_robust th =
let val fth = Thm.freezeT th
val {prop, tpairs, thy, ...} = rep_thm fth
in
case foldr add_term_vars [] (prop :: Thm.terms_of_tpairs tpairs) of
[] => (fth, fn i => fn x => x) (*No vars: nothing to do!*)
| vars =>
let fun newName (Var(ix,_)) = (ix, gensym (string_of_indexname ix))
val alist = map newName vars
fun mk_inst (Var(v,T)) =
(cterm_of thy (Var(v,T)),
cterm_of thy (Free(((the o AList.lookup (op =) alist) v), T)))
val insts = map mk_inst vars
fun thaw i th' = (*i is non-negative increment for Var indexes*)
th' |> forall_intr_list (map #2 insts)
|> forall_elim_list (map (Thm.cterm_incr_indexes i o #1) insts)
in (Thm.instantiate ([],insts) fth, thaw) end
end;
(*Basic version of the function above. No option to rename Vars apart in thaw.
The Frees created from Vars have nice names. FIXME: does not check for
clashes with variables in the assumptions, so delete and use freeze_thaw_robust instead?*)
fun freeze_thaw th =
let val fth = Thm.freezeT th
val {prop, tpairs, thy, ...} = rep_thm fth
in
case foldr add_term_vars [] (prop :: Thm.terms_of_tpairs tpairs) of
[] => (fth, fn x => x)
| vars =>
let fun newName (Var(ix,_), (pairs,used)) =
let val v = Name.variant used (string_of_indexname ix)
in ((ix,v)::pairs, v::used) end;
val (alist, _) = foldr newName ([], Library.foldr add_term_names
(prop :: Thm.terms_of_tpairs tpairs, [])) vars
fun mk_inst (Var(v,T)) =
(cterm_of thy (Var(v,T)),
cterm_of thy (Free(((the o AList.lookup (op =) alist) v), T)))
val insts = map mk_inst vars
fun thaw th' =
th' |> forall_intr_list (map #2 insts)
|> forall_elim_list (map #1 insts)
in (Thm.instantiate ([],insts) fth, thaw) end
end;
(*Rotates a rule's premises to the left by k*)
val rotate_prems = permute_prems 0;
(* permute prems, where the i-th position in the argument list (counting from 0)
gives the position within the original thm to be transferred to position i.
Any remaining trailing positions are left unchanged. *)
val rearrange_prems = let
fun rearr new [] thm = thm
| rearr new (p::ps) thm = rearr (new+1)
(map (fn q => if new<=q andalso q<p then q+1 else q) ps)
(permute_prems (new+1) (new-p) (permute_prems new (p-new) thm))
in rearr 0 end;
(*Resolution: exactly one resolvent must be produced.*)
fun tha RSN (i,thb) =
case Seq.chop 2 (biresolution false [(false,tha)] i thb) of
([th],_) => th
| ([],_) => raise THM("RSN: no unifiers", i, [tha,thb])
| _ => raise THM("RSN: multiple unifiers", i, [tha,thb]);
(*resolution: P==>Q, Q==>R gives P==>R. *)
fun tha RS thb = tha RSN (1,thb);
(*For joining lists of rules*)
fun thas RLN (i,thbs) =
let val resolve = biresolution false (map (pair false) thas) i
fun resb thb = Seq.list_of (resolve thb) handle THM _ => []
in maps resb thbs end;
fun thas RL thbs = thas RLN (1,thbs);
(*Resolve a list of rules against bottom_rl from right to left;
makes proof trees*)
fun rls MRS bottom_rl =
let fun rs_aux i [] = bottom_rl
| rs_aux i (rl::rls) = rl RSN (i, rs_aux (i+1) rls)
in rs_aux 1 rls end;
(*As above, but for rule lists*)
fun rlss MRL bottom_rls =
let fun rs_aux i [] = bottom_rls
| rs_aux i (rls::rlss) = rls RLN (i, rs_aux (i+1) rlss)
in rs_aux 1 rlss end;
(*A version of MRS with more appropriate argument order*)
fun bottom_rl OF rls = rls MRS bottom_rl;
(*compose Q and [...,Qi,Q(i+1),...]==>R to [...,Q(i+1),...]==>R
with no lifting or renaming! Q may contain ==> or meta-quants
ALWAYS deletes premise i *)
fun compose(tha,i,thb) =
Seq.list_of (bicompose false (false,tha,0) i thb);
fun compose_single (tha,i,thb) =
(case compose (tha,i,thb) of
[th] => th
| _ => raise THM ("compose: unique result expected", i, [tha,thb]));
(*compose Q and [Q1,Q2,...,Qk]==>R to [Q2,...,Qk]==>R getting unique result*)
fun tha COMP thb =
case compose(tha,1,thb) of
[th] => th
| _ => raise THM("COMP", 1, [tha,thb]);
(** theorem equality **)
(*True if the two theorems have the same theory.*)
val eq_thm_thy = eq_thy o pairself Thm.theory_of_thm;
(*True if the two theorems have the same prop field, ignoring hyps, der, etc.*)
val eq_thm_prop = op aconv o pairself Thm.full_prop_of;
(*Useful "distance" function for BEST_FIRST*)
val size_of_thm = size_of_term o Thm.full_prop_of;
(*maintain lists of theorems --- preserving canonical order*)
val del_rule = remove eq_thm_prop;
fun add_rule th = cons th o del_rule th;
val merge_rules = Library.merge eq_thm_prop;
(*pattern equivalence*)
fun equiv_thm ths =
Pattern.equiv (Theory.merge (pairself Thm.theory_of_thm ths)) (pairself Thm.full_prop_of ths);
(*** Meta-Rewriting Rules ***)
fun read_prop s = read_cterm ProtoPure.thy (s, propT);
fun store_thm name thm = hd (PureThy.smart_store_thms (name, [thm]));
fun store_standard_thm name thm = store_thm name (standard thm);
fun store_thm_open name thm = hd (PureThy.smart_store_thms_open (name, [thm]));
fun store_standard_thm_open name thm = store_thm_open name (standard' thm);
val reflexive_thm =
let val cx = cert (Var(("x",0),TVar(("'a",0),[])))
in store_standard_thm_open "reflexive" (Thm.reflexive cx) end;
val symmetric_thm =
let val xy = read_prop "x == y"
in store_standard_thm_open "symmetric" (Thm.implies_intr xy (Thm.symmetric (Thm.assume xy))) end;
val transitive_thm =
let val xy = read_prop "x == y"
val yz = read_prop "y == z"
val xythm = Thm.assume xy and yzthm = Thm.assume yz
in store_standard_thm_open "transitive" (Thm.implies_intr yz (Thm.transitive xythm yzthm)) end;
fun symmetric_fun thm = thm RS symmetric_thm;
fun extensional eq =
let val eq' =
abstract_rule "x" (Thm.dest_arg (fst (dest_equals (cprop_of eq)))) eq
in equal_elim (eta_conversion (cprop_of eq')) eq' end;
val equals_cong =
store_standard_thm_open "equals_cong" (Thm.reflexive (read_prop "x == y"));
val imp_cong =
let
val ABC = read_prop "PROP A ==> PROP B == PROP C"
val AB = read_prop "PROP A ==> PROP B"
val AC = read_prop "PROP A ==> PROP C"
val A = read_prop "PROP A"
in
store_standard_thm_open "imp_cong" (implies_intr ABC (equal_intr
(implies_intr AB (implies_intr A
(equal_elim (implies_elim (assume ABC) (assume A))
(implies_elim (assume AB) (assume A)))))
(implies_intr AC (implies_intr A
(equal_elim (symmetric (implies_elim (assume ABC) (assume A)))
(implies_elim (assume AC) (assume A)))))))
end;
val swap_prems_eq =
let
val ABC = read_prop "PROP A ==> PROP B ==> PROP C"
val BAC = read_prop "PROP B ==> PROP A ==> PROP C"
val A = read_prop "PROP A"
val B = read_prop "PROP B"
in
store_standard_thm_open "swap_prems_eq" (equal_intr
(implies_intr ABC (implies_intr B (implies_intr A
(implies_elim (implies_elim (assume ABC) (assume A)) (assume B)))))
(implies_intr BAC (implies_intr A (implies_intr B
(implies_elim (implies_elim (assume BAC) (assume B)) (assume A))))))
end;
val imp_cong_rule = combination o combination (reflexive implies);
local
val dest_eq = dest_equals o cprop_of
val rhs_of = snd o dest_eq
in
fun beta_eta_conversion t =
let val thm = beta_conversion true t
in transitive thm (eta_conversion (rhs_of thm)) end
end;
fun eta_long_conversion ct = transitive (beta_eta_conversion ct)
(symmetric (beta_eta_conversion (cterm_fun (Pattern.eta_long []) ct)));
(*Contract all eta-redexes in the theorem, lest they give rise to needless abstractions*)
fun eta_contraction_rule th =
equal_elim (eta_conversion (cprop_of th)) th;
val abs_def =
let
fun contract_lhs th =
Thm.transitive (Thm.symmetric (beta_eta_conversion (fst (dest_equals (cprop_of th))))) th;
fun abstract cx th = Thm.abstract_rule
(case Thm.term_of cx of Var ((x, _), _) => x | Free (x, _) => x | _ => "x") cx th
handle THM _ => raise THM ("Malformed definitional equation", 0, [th]);
in
contract_lhs
#> `(snd o strip_comb o fst o dest_equals o cprop_of)
#-> fold_rev abstract
#> contract_lhs
end;
(*rewrite B in !!x1 ... xn. B*)
fun forall_conv 0 cv ct = cv ct
| forall_conv n cv ct =
(case try Thm.dest_comb ct of
NONE => cv ct
| SOME (A, B) =>
(case (term_of A, term_of B) of
(Const ("all", _), Abs (x, _, _)) =>
let val (v, B') = Thm.dest_abs (SOME (gensym "all_")) B in
Thm.combination (Thm.reflexive A)
(Thm.abstract_rule x v (forall_conv (n - 1) cv B'))
end
| _ => cv ct));
(*rewrite B in A1 ==> ... ==> An ==> B*)
fun concl_conv 0 cv ct = cv ct
| concl_conv n cv ct =
(case try dest_implies ct of
NONE => cv ct
| SOME (A, B) => imp_cong_rule (reflexive A) (concl_conv (n - 1) cv B));
(*rewrite the A's in A1 ==> ... ==> An ==> B*)
fun prems_conv 0 _ = reflexive
| prems_conv n cv =
let
fun conv i ct =
if i = n + 1 then reflexive ct
else
(case try dest_implies ct of
NONE => reflexive ct
| SOME (A, B) => imp_cong_rule (cv i A) (conv (i + 1) B));
in conv 1 end;
fun goals_conv pred cv = prems_conv ~1 (fn i => if pred i then cv else reflexive);
fun fconv_rule cv th = equal_elim (cv (cprop_of th)) th;
(*** Some useful meta-theorems ***)
(*The rule V/V, obtains assumption solving for eresolve_tac*)
val asm_rl = store_standard_thm_open "asm_rl" (Thm.trivial (read_prop "PROP ?psi"));
val _ = store_thm "_" asm_rl;
(*Meta-level cut rule: [| V==>W; V |] ==> W *)
val cut_rl =
store_standard_thm_open "cut_rl"
(Thm.trivial (read_prop "PROP ?psi ==> PROP ?theta"));
(*Generalized elim rule for one conclusion; cut_rl with reversed premises:
[| PROP V; PROP V ==> PROP W |] ==> PROP W *)
val revcut_rl =
let val V = read_prop "PROP V"
and VW = read_prop "PROP V ==> PROP W";
in
store_standard_thm_open "revcut_rl"
(implies_intr V (implies_intr VW (implies_elim (assume VW) (assume V))))
end;
(*for deleting an unwanted assumption*)
val thin_rl =
let val V = read_prop "PROP V"
and W = read_prop "PROP W";
in store_standard_thm_open "thin_rl" (implies_intr V (implies_intr W (assume W))) end;
(* (!!x. PROP ?V) == PROP ?V Allows removal of redundant parameters*)
val triv_forall_equality =
let val V = read_prop "PROP V"
and QV = read_prop "!!x::'a. PROP V"
and x = cert (Free ("x", Term.aT []));
in
store_standard_thm_open "triv_forall_equality"
(equal_intr (implies_intr QV (forall_elim x (assume QV)))
(implies_intr V (forall_intr x (assume V))))
end;
(* (PROP ?Phi ==> PROP ?Phi ==> PROP ?Psi) ==>
(PROP ?Phi ==> PROP ?Psi)
*)
val distinct_prems_rl =
let
val AAB = read_prop "PROP Phi ==> PROP Phi ==> PROP Psi"
val A = read_prop "PROP Phi";
in
store_standard_thm_open "distinct_prems_rl"
(implies_intr_list [AAB, A] (implies_elim_list (assume AAB) [assume A, assume A]))
end;
(* (PROP ?PhiA ==> PROP ?PhiB ==> PROP ?Psi) ==>
(PROP ?PhiB ==> PROP ?PhiA ==> PROP ?Psi)
`thm COMP swap_prems_rl' swaps the first two premises of `thm'
*)
val swap_prems_rl =
let val cmajor = read_prop "PROP PhiA ==> PROP PhiB ==> PROP Psi";
val major = assume cmajor;
val cminor1 = read_prop "PROP PhiA";
val minor1 = assume cminor1;
val cminor2 = read_prop "PROP PhiB";
val minor2 = assume cminor2;
in store_standard_thm_open "swap_prems_rl"
(implies_intr cmajor (implies_intr cminor2 (implies_intr cminor1
(implies_elim (implies_elim major minor1) minor2))))
end;
(* [| PROP ?phi ==> PROP ?psi; PROP ?psi ==> PROP ?phi |]
==> PROP ?phi == PROP ?psi
Introduction rule for == as a meta-theorem.
*)
val equal_intr_rule =
let val PQ = read_prop "PROP phi ==> PROP psi"
and QP = read_prop "PROP psi ==> PROP phi"
in
store_standard_thm_open "equal_intr_rule"
(implies_intr PQ (implies_intr QP (equal_intr (assume PQ) (assume QP))))
end;
(* PROP ?phi == PROP ?psi ==> PROP ?phi ==> PROP ?psi *)
val equal_elim_rule1 =
let val eq = read_prop "PROP phi == PROP psi"
and P = read_prop "PROP phi"
in store_standard_thm_open "equal_elim_rule1"
(Thm.equal_elim (assume eq) (assume P) |> implies_intr_list [eq, P])
end;
(* PROP ?psi == PROP ?phi ==> PROP ?phi ==> PROP ?psi *)
val equal_elim_rule2 =
store_standard_thm_open "equal_elim_rule2" (symmetric_thm RS equal_elim_rule1);
(* "[| PROP ?phi; PROP ?phi; PROP ?psi |] ==> PROP ?psi" *)
val remdups_rl =
let val P = read_prop "PROP phi" and Q = read_prop "PROP psi";
in store_standard_thm_open "remdups_rl" (implies_intr_list [P, P, Q] (Thm.assume Q)) end;
(*(PROP ?phi ==> (!!x. PROP ?psi(x))) == (!!x. PROP ?phi ==> PROP ?psi(x))
Rewrite rule for HHF normalization.*)
val norm_hhf_eq =
let
val aT = TFree ("'a", []);
val all = Term.all aT;
val x = Free ("x", aT);
val phi = Free ("phi", propT);
val psi = Free ("psi", aT --> propT);
val cx = cert x;
val cphi = cert phi;
val lhs = cert (Logic.mk_implies (phi, all $ Abs ("x", aT, psi $ Bound 0)));
val rhs = cert (all $ Abs ("x", aT, Logic.mk_implies (phi, psi $ Bound 0)));
in
Thm.equal_intr
(Thm.implies_elim (Thm.assume lhs) (Thm.assume cphi)
|> Thm.forall_elim cx
|> Thm.implies_intr cphi
|> Thm.forall_intr cx
|> Thm.implies_intr lhs)
(Thm.implies_elim
(Thm.assume rhs |> Thm.forall_elim cx) (Thm.assume cphi)
|> Thm.forall_intr cx
|> Thm.implies_intr cphi
|> Thm.implies_intr rhs)
|> store_standard_thm_open "norm_hhf_eq"
end;
val norm_hhf_prop = Logic.dest_equals (Thm.prop_of norm_hhf_eq);
fun is_norm_hhf tm =
let
fun is_norm (Const ("==>", _) $ _ $ (Const ("all", _) $ _)) = false
| is_norm (t $ u) = is_norm t andalso is_norm u
| is_norm (Abs (_, _, t)) = is_norm t
| is_norm _ = true;
in is_norm (Envir.beta_eta_contract tm) end;
fun norm_hhf thy t =
if is_norm_hhf t then t
else Pattern.rewrite_term thy [norm_hhf_prop] [] t;
fun norm_hhf_cterm ct =
if is_norm_hhf (Thm.term_of ct) then ct
else cterm_fun (Pattern.rewrite_term (Thm.theory_of_cterm ct) [norm_hhf_prop] []) ct;
(* var indexes *)
fun incr_indexes th = Thm.incr_indexes (Thm.maxidx_of th + 1);
fun incr_indexes2 th1 th2 =
Thm.incr_indexes (Int.max (Thm.maxidx_of th1, Thm.maxidx_of th2) + 1);
fun th1 INCR_COMP th2 = incr_indexes th2 th1 COMP th2;
fun th1 COMP_INCR th2 = th1 COMP incr_indexes th1 th2;
(*** Instantiate theorem th, reading instantiations in theory thy ****)
(*Version that normalizes the result: Thm.instantiate no longer does that*)
fun instantiate instpair th =
Thm.adjust_maxidx_thm ~1 (Thm.instantiate instpair th COMP_INCR asm_rl);
fun read_instantiate_sg' thy sinsts th =
let val ts = types_sorts th;
val used = add_used th [];
in instantiate (read_insts thy ts ts used sinsts) th end;
fun read_instantiate_sg thy sinsts th =
read_instantiate_sg' thy (map (apfst Syntax.read_indexname) sinsts) th;
(*Instantiate theorem th, reading instantiations under theory of th*)
fun read_instantiate sinsts th =
read_instantiate_sg (Thm.theory_of_thm th) sinsts th;
fun read_instantiate' sinsts th =
read_instantiate_sg' (Thm.theory_of_thm th) sinsts th;
(*Left-to-right replacements: tpairs = [...,(vi,ti),...].
Instantiates distinct Vars by terms, inferring type instantiations. *)
local
fun add_types ((ct,cu), (thy,tye,maxidx)) =
let val {thy=thyt, t=t, T= T, maxidx=maxt,...} = rep_cterm ct
and {thy=thyu, t=u, T= U, maxidx=maxu,...} = rep_cterm cu;
val maxi = Int.max(maxidx, Int.max(maxt, maxu));
val thy' = Theory.merge(thy, Theory.merge(thyt, thyu))
val (tye',maxi') = Sign.typ_unify thy' (T, U) (tye, maxi)
handle Type.TUNIFY => raise TYPE("Ill-typed instantiation", [T,U], [t,u])
in (thy', tye', maxi') end;
in
fun cterm_instantiate ctpairs0 th =
let val (thy,tye,_) = foldr add_types (Thm.theory_of_thm th, Vartab.empty, 0) ctpairs0
fun instT(ct,cu) =
let val inst = cterm_of thy o Term.map_types (Envir.norm_type tye) o term_of
in (inst ct, inst cu) end
fun ctyp2 (ixn, (S, T)) = (ctyp_of thy (TVar (ixn, S)), ctyp_of thy (Envir.norm_type tye T))
in instantiate (map ctyp2 (Vartab.dest tye), map instT ctpairs0) th end
handle TERM _ =>
raise THM("cterm_instantiate: incompatible theories",0,[th])
| TYPE (msg, _, _) => raise THM(msg, 0, [th])
end;
(* global schematic variables *)
fun unvarify th =
let
val thy = Thm.theory_of_thm th;
val cert = Thm.cterm_of thy;
val certT = Thm.ctyp_of thy;
val prop = Thm.full_prop_of th;
val _ = map Logic.unvarify (prop :: Thm.hyps_of th)
handle TERM (msg, _) => raise THM (msg, 0, [th]);
val instT0 = rev (Term.add_tvars prop []) |> map (fn v as ((a, _), S) => (v, TFree (a, S)));
val instT = map (fn (v, T) => (certT (TVar v), certT T)) instT0;
val inst = rev (Term.add_vars prop []) |> map (fn ((a, i), T) =>
let val T' = TermSubst.instantiateT instT0 T
in (cert (Var ((a, i), T')), cert (Free ((a, T')))) end);
in Thm.instantiate (instT, inst) th end;
(** protected propositions and embedded terms **)
local
val A = cert (Free ("A", propT));
val prop_def = unvarify ProtoPure.prop_def;
val term_def = unvarify ProtoPure.term_def;
in
val protect = Thm.capply (cert Logic.protectC);
val protectI = store_thm "protectI" (PureThy.kind_rule Thm.internalK (standard
(Thm.equal_elim (Thm.symmetric prop_def) (Thm.assume A))));
val protectD = store_thm "protectD" (PureThy.kind_rule Thm.internalK (standard
(Thm.equal_elim prop_def (Thm.assume (protect A)))));
val protect_cong = store_standard_thm_open "protect_cong" (Thm.reflexive (protect A));
val termI = store_thm "termI" (PureThy.kind_rule Thm.internalK (standard
(Thm.equal_elim (Thm.symmetric term_def) (Thm.forall_intr A (Thm.trivial A)))));
end;
fun implies_intr_protected asms th =
let val asms' = map protect asms in
implies_elim_list
(implies_intr_list asms th)
(map (fn asm' => Thm.assume asm' RS protectD) asms')
|> implies_intr_list asms'
end;
fun mk_term ct =
let
val {thy, T, ...} = Thm.rep_cterm ct;
val cert = Thm.cterm_of thy;
val certT = Thm.ctyp_of thy;
val a = certT (TVar (("'a", 0), []));
val x = cert (Var (("x", 0), T));
in Thm.instantiate ([(a, certT T)], [(x, ct)]) termI end;
fun dest_term th =
let val cprop = strip_imp_concl (Thm.cprop_of th) in
if can Logic.dest_term (Thm.term_of cprop) then
Thm.dest_arg cprop
else raise THM ("dest_term", 0, [th])
end;
fun cterm_rule f = dest_term o f o mk_term;
fun term_rule thy f t = Thm.term_of (cterm_rule f (Thm.cterm_of thy t));
(** variations on instantiate **)
(* instantiate by left-to-right occurrence of variables *)
fun instantiate' cTs cts thm =
let
fun err msg =
raise TYPE ("instantiate': " ^ msg,
map_filter (Option.map Thm.typ_of) cTs,
map_filter (Option.map Thm.term_of) cts);
fun inst_of (v, ct) =
(Thm.cterm_of (Thm.theory_of_cterm ct) (Var v), ct)
handle TYPE (msg, _, _) => err msg;
fun tyinst_of (v, cT) =
(Thm.ctyp_of (Thm.theory_of_ctyp cT) (TVar v), cT)
handle TYPE (msg, _, _) => err msg;
fun zip_vars xs ys =
zip_options xs ys handle Library.UnequalLengths =>
err "more instantiations than variables in thm";
(*instantiate types first!*)
val thm' =
if forall is_none cTs then thm
else Thm.instantiate
(map tyinst_of (zip_vars (rev (fold_terms Term.add_tvars thm [])) cTs), []) thm;
val thm'' =
if forall is_none cts then thm'
else Thm.instantiate
([], map inst_of (zip_vars (rev (fold_terms Term.add_vars thm' [])) cts)) thm';
in thm'' end;
(** renaming of bound variables **)
(* replace bound variables x_i in thm by y_i *)
(* where vs = [(x_1, y_1), ..., (x_n, y_n)] *)
fun rename_bvars [] thm = thm
| rename_bvars vs thm =
let
val {thy, prop, ...} = rep_thm thm;
fun ren (Abs (x, T, t)) = Abs (AList.lookup (op =) vs x |> the_default x, T, ren t)
| ren (t $ u) = ren t $ ren u
| ren t = t;
in equal_elim (reflexive (cterm_of thy (ren prop))) thm end;
(* renaming in left-to-right order *)
fun rename_bvars' xs thm =
let
val {thy, prop, ...} = rep_thm thm;
fun rename [] t = ([], t)
| rename (x' :: xs) (Abs (x, T, t)) =
let val (xs', t') = rename xs t
in (xs', Abs (the_default x x', T, t')) end
| rename xs (t $ u) =
let
val (xs', t') = rename xs t;
val (xs'', u') = rename xs' u
in (xs'', t' $ u') end
| rename xs t = (xs, t);
in case rename xs prop of
([], prop') => equal_elim (reflexive (cterm_of thy prop')) thm
| _ => error "More names than abstractions in theorem"
end;
(** multi_resolve **)
local
fun res th i rule =
Thm.biresolution false [(false, th)] i rule handle THM _ => Seq.empty;
fun multi_res _ [] rule = Seq.single rule
| multi_res i (th :: ths) rule = Seq.maps (res th i) (multi_res (i + 1) ths rule);
in
val multi_resolve = multi_res 1;
fun multi_resolves facts rules = Seq.maps (multi_resolve facts) (Seq.of_list rules);
end;
end;
structure BasicDrule: BASIC_DRULE = Drule;
open BasicDrule;