First release of interpretation commands.
(* Title: Pure/thm.ML
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1994 University of Cambridge
The core of Isabelle's Meta Logic: certified types and terms, meta
theorems, meta rules (including lifting and resolution).
*)
signature BASIC_THM =
sig
(*certified types*)
type ctyp
val rep_ctyp : ctyp -> {sign: Sign.sg, T: typ}
val typ_of : ctyp -> typ
val ctyp_of : Sign.sg -> typ -> ctyp
val read_ctyp : Sign.sg -> string -> ctyp
(*certified terms*)
type cterm
exception CTERM of string
val rep_cterm : cterm -> {sign: Sign.sg, t: term, T: typ, maxidx: int}
val crep_cterm : cterm -> {sign: Sign.sg, t: term, T: ctyp, maxidx: int}
val sign_of_cterm : cterm -> Sign.sg
val term_of : cterm -> term
val cterm_of : Sign.sg -> term -> cterm
val ctyp_of_term : cterm -> ctyp
val read_cterm : Sign.sg -> string * typ -> cterm
val cterm_fun : (term -> term) -> (cterm -> cterm)
val adjust_maxidx : cterm -> cterm
val read_def_cterm :
Sign.sg * (indexname -> typ option) * (indexname -> sort option) ->
string list -> bool -> string * typ -> cterm * (indexname * typ) list
val read_def_cterms :
Sign.sg * (indexname -> typ option) * (indexname -> sort option) ->
string list -> bool -> (string * typ)list
-> cterm list * (indexname * typ)list
type tag (* = string * string list *)
(*meta theorems*)
type thm
val rep_thm : thm -> {sign: Sign.sg, der: bool * Proofterm.proof, maxidx: int,
shyps: sort list, hyps: term list,
tpairs: (term * term) list, prop: term}
val crep_thm : thm -> {sign: Sign.sg, der: bool * Proofterm.proof, maxidx: int,
shyps: sort list, hyps: cterm list,
tpairs: (cterm * cterm) list, prop: cterm}
exception THM of string * int * thm list
type 'a attribute (* = 'a * thm -> 'a * thm *)
val eq_thm : thm * thm -> bool
val sign_of_thm : thm -> Sign.sg
val prop_of : thm -> term
val proof_of : thm -> Proofterm.proof
val transfer_sg : Sign.sg -> thm -> thm
val transfer : theory -> thm -> thm
val tpairs_of : thm -> (term * term) list
val prems_of : thm -> term list
val nprems_of : thm -> int
val concl_of : thm -> term
val cprop_of : thm -> cterm
val extra_shyps : thm -> sort list
val strip_shyps : thm -> thm
val get_axiom_i : theory -> string -> thm
val get_axiom : theory -> xstring -> thm
val def_name : string -> string
val get_def : theory -> xstring -> thm
val axioms_of : theory -> (string * thm) list
(*meta rules*)
val assume : cterm -> thm
val compress : thm -> thm
val implies_intr : cterm -> thm -> thm
val implies_elim : thm -> thm -> thm
val forall_intr : cterm -> thm -> thm
val forall_elim : cterm -> thm -> thm
val reflexive : cterm -> thm
val symmetric : thm -> thm
val transitive : thm -> thm -> thm
val beta_conversion : bool -> cterm -> thm
val eta_conversion : cterm -> thm
val abstract_rule : string -> cterm -> thm -> thm
val combination : thm -> thm -> thm
val equal_intr : thm -> thm -> thm
val equal_elim : thm -> thm -> thm
val implies_intr_hyps : thm -> thm
val flexflex_rule : thm -> thm Seq.seq
val instantiate :
(indexname * ctyp) list * (cterm * cterm) list -> thm -> thm
val trivial : cterm -> thm
val class_triv : Sign.sg -> class -> thm
val varifyT : thm -> thm
val varifyT' : string list -> thm -> thm * (string * indexname) list
val freezeT : thm -> thm
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
val permute_prems : int -> int -> thm -> thm
val rename_params_rule: string list * int -> thm -> thm
val bicompose : bool -> bool * thm * int ->
int -> thm -> thm Seq.seq
val biresolution : bool -> (bool * thm) list ->
int -> thm -> thm Seq.seq
val invoke_oracle_i : theory -> string -> Sign.sg * Object.T -> thm
val invoke_oracle : theory -> xstring -> Sign.sg * Object.T -> thm
end;
signature THM =
sig
include BASIC_THM
val dest_ctyp : ctyp -> ctyp list
val dest_comb : cterm -> cterm * cterm
val dest_abs : string option -> cterm -> cterm * cterm
val capply : cterm -> cterm -> cterm
val cabs : cterm -> cterm -> cterm
val major_prem_of : thm -> term
val no_prems : thm -> bool
val no_attributes : 'a -> 'a * 'b attribute list
val apply_attributes : ('a * thm) * 'a attribute list -> ('a * thm)
val applys_attributes : ('a * thm list) * 'a attribute list -> ('a * thm list)
val get_name_tags : thm -> string * tag list
val put_name_tags : string * tag list -> thm -> thm
val name_of_thm : thm -> string
val tags_of_thm : thm -> tag list
val name_thm : string * thm -> thm
val rename_boundvars : term -> term -> thm -> thm
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 terms_of_tpairs : (term * term) list -> term list
end;
structure Thm: THM =
struct
(*** Certified terms and types ***)
(** certified types **)
(*certified typs under a signature*)
datatype ctyp = Ctyp of {sign_ref: Sign.sg_ref, T: typ};
fun rep_ctyp (Ctyp {sign_ref, T}) = {sign = Sign.deref sign_ref, T = T};
fun typ_of (Ctyp {T, ...}) = T;
fun ctyp_of sign T =
Ctyp {sign_ref = Sign.self_ref sign, T = Sign.certify_typ sign T};
fun read_ctyp sign s =
Ctyp {sign_ref = Sign.self_ref sign, T = Sign.read_typ (sign, K NONE) s};
fun dest_ctyp (Ctyp {sign_ref, T = Type (s, Ts)}) =
map (fn T => Ctyp {sign_ref = sign_ref, T = T}) Ts
| dest_ctyp ct = [ct];
(** certified terms **)
(*certified terms under a signature, with checked typ and maxidx of Vars*)
datatype cterm = Cterm of {sign_ref: Sign.sg_ref, t: term, T: typ, maxidx: int};
fun rep_cterm (Cterm {sign_ref, t, T, maxidx}) =
{sign = Sign.deref sign_ref, t = t, T = T, maxidx = maxidx};
fun crep_cterm (Cterm {sign_ref, t, T, maxidx}) =
{sign = Sign.deref sign_ref, t = t, T = Ctyp {sign_ref = sign_ref, T = T},
maxidx = maxidx};
fun sign_of_cterm (Cterm {sign_ref, ...}) = Sign.deref sign_ref;
fun term_of (Cterm {t, ...}) = t;
fun ctyp_of_term (Cterm {sign_ref, T, ...}) = Ctyp {sign_ref = sign_ref, T = T};
(*create a cterm by checking a "raw" term with respect to a signature*)
fun cterm_of sign tm =
let val (t, T, maxidx) = Sign.certify_term (Sign.pp sign) sign tm
in Cterm {sign_ref = Sign.self_ref sign, t = t, T = T, maxidx = maxidx}
end;
fun cterm_fun f (Cterm {sign_ref, t, ...}) = cterm_of (Sign.deref sign_ref) (f t);
exception CTERM of string;
(*Destruct application in cterms*)
fun dest_comb (Cterm {sign_ref, T, maxidx, t = A $ B}) =
let val typeA = fastype_of A;
val typeB =
case typeA of Type("fun",[S,T]) => S
| _ => error "Function type expected in dest_comb";
in
(Cterm {sign_ref=sign_ref, maxidx=maxidx, t=A, T=typeA},
Cterm {sign_ref=sign_ref, maxidx=maxidx, t=B, T=typeB})
end
| dest_comb _ = raise CTERM "dest_comb";
(*Destruct abstraction in cterms*)
fun dest_abs a (Cterm {sign_ref, T as Type("fun",[_,S]), maxidx, t=Abs(x,ty,M)}) =
let val (y,N) = variant_abs (getOpt (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";
(*Makes maxidx precise: it is often too big*)
fun adjust_maxidx (ct as Cterm {sign_ref, T, t, maxidx, ...}) =
if maxidx = ~1 then ct
else Cterm {sign_ref = sign_ref, T = T, maxidx = maxidx_of_term t, t = t};
(*Form cterm out of a function and an argument*)
fun capply (Cterm {t=f, sign_ref=sign_ref1, T=Type("fun",[dty,rty]), maxidx=maxidx1})
(Cterm {t=x, sign_ref=sign_ref2, T, maxidx=maxidx2}) =
if T = dty then
Cterm{t = if maxidx1 >= 0 andalso maxidx2 >= 0 then Sign.nodup_vars (f $ x)
else f $ x, (*no new Vars: no expensive check!*)
sign_ref=Sign.merge_refs(sign_ref1,sign_ref2), T=rty,
maxidx=Int.max(maxidx1, maxidx2)}
else raise CTERM "capply: types don't agree"
| capply _ _ = raise CTERM "capply: first arg is not a function"
fun cabs (Cterm {t=t1, sign_ref=sign_ref1, T=T1, maxidx=maxidx1})
(Cterm {t=t2, sign_ref=sign_ref2, T=T2, maxidx=maxidx2}) =
Cterm {t=Sign.nodup_vars (lambda t1 t2), sign_ref=Sign.merge_refs(sign_ref1,sign_ref2),
T = T1 --> T2, maxidx=Int.max(maxidx1, maxidx2)}
handle TERM _ => raise CTERM "cabs: first arg is not a 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 (valOf (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 (ct as Cterm {sign_ref, maxidx, t, T}) =
if i < 0 then raise CTERM "negative increment" else
if i = 0 then ct else
Cterm {sign_ref = sign_ref, maxidx = maxidx + i,
t = Logic.incr_indexes ([], i) t, T = Term.incr_tvar i T};
(** read cterms **) (*exception ERROR*)
(*read terms, infer types, certify terms*)
fun read_def_cterms (sign, types, sorts) used freeze sTs =
let
val (ts', tye) = Sign.read_def_terms (sign, types, sorts) used freeze sTs;
val cts = map (cterm_of sign) ts'
handle TYPE (msg, _, _) => error msg
| TERM (msg, _) => error msg;
in (cts, tye) end;
(*read term, infer types, certify term*)
fun read_def_cterm args used freeze aT =
let val ([ct],tye) = read_def_cterms args used freeze [aT]
in (ct,tye) end;
fun read_cterm sign = #1 o read_def_cterm (sign, K NONE, K NONE) [] true;
(*tags provide additional comment, apart from the axiom/theorem name*)
type tag = string * string list;
(*** Meta theorems ***)
structure Pt = Proofterm;
datatype thm = Thm of
{sign_ref: Sign.sg_ref, (*mutable reference to signature*)
der: bool * Pt.proof, (*derivation*)
maxidx: int, (*maximum index of any Var or TVar*)
shyps: sort list, (*sort hypotheses*)
hyps: term list, (*hypotheses*)
tpairs: (term * term) list, (*flex-flex pairs*)
prop: term}; (*conclusion*)
fun terms_of_tpairs tpairs = List.concat (map (op @ o pairself single) tpairs);
fun attach_tpairs tpairs prop =
Logic.list_implies (map Logic.mk_equals tpairs, prop);
fun rep_thm (Thm {sign_ref, der, maxidx, shyps, hyps, tpairs, prop}) =
{sign = Sign.deref sign_ref, der = der, maxidx = maxidx,
shyps = shyps, hyps = hyps, tpairs = tpairs, prop = prop};
(*Version of rep_thm returning cterms instead of terms*)
fun crep_thm (Thm {sign_ref, der, maxidx, shyps, hyps, tpairs, prop}) =
let fun ctermf max t = Cterm{sign_ref=sign_ref, t=t, T=propT, maxidx=max};
in {sign = Sign.deref sign_ref, der = der, maxidx = maxidx, shyps = shyps,
hyps = map (ctermf ~1) hyps,
tpairs = map (pairself (ctermf maxidx)) tpairs,
prop = ctermf maxidx prop}
end;
(*errors involving theorems*)
exception THM of string * int * thm list;
(*attributes subsume any kind of rules or addXXXs modifiers*)
type 'a attribute = 'a * thm -> 'a * thm;
fun no_attributes x = (x, []);
fun apply_attributes (x_th, atts) = Library.apply atts x_th;
fun applys_attributes (x_ths, atts) = foldl_map (Library.apply atts) x_ths;
fun eq_thm (th1, th2) =
let
val {sign = sg1, shyps = shyps1, hyps = hyps1, tpairs = tpairs1, prop = prop1, ...} =
rep_thm th1;
val {sign = sg2, shyps = shyps2, hyps = hyps2, tpairs = tpairs2, prop = prop2, ...} =
rep_thm th2;
in
Sign.joinable (sg1, sg2) andalso
Sorts.eq_set_sort (shyps1, shyps2) andalso
aconvs (hyps1, hyps2) andalso
aconvs (terms_of_tpairs tpairs1, terms_of_tpairs tpairs2) andalso
prop1 aconv prop2
end;
fun sign_of_thm (Thm {sign_ref, ...}) = Sign.deref sign_ref;
fun prop_of (Thm {prop, ...}) = prop;
fun proof_of (Thm {der = (_, proof), ...}) = proof;
(*merge signatures of two theorems; raise exception if incompatible*)
fun merge_thm_sgs
(th1 as Thm {sign_ref = sgr1, ...}, th2 as Thm {sign_ref = sgr2, ...}) =
Sign.merge_refs (sgr1, sgr2) handle TERM (msg, _) => raise THM (msg, 0, [th1, th2]);
(*transfer thm to super theory (non-destructive)*)
fun transfer_sg sign' thm =
let
val Thm {sign_ref, der, maxidx, shyps, hyps, tpairs, prop} = thm;
val sign = Sign.deref sign_ref;
in
if Sign.eq_sg (sign, sign') then thm
else if Sign.subsig (sign, sign') then
Thm {sign_ref = Sign.self_ref sign', der = der, maxidx = maxidx,
shyps = shyps, hyps = hyps, tpairs = tpairs, prop = prop}
else raise THM ("transfer: not a super theory", 0, [thm])
end;
val transfer = transfer_sg o Theory.sign_of;
(*maps object-rule to tpairs*)
fun tpairs_of (Thm {tpairs, ...}) = tpairs;
(*maps object-rule to premises*)
fun prems_of (Thm {prop, ...}) =
Logic.strip_imp_prems prop;
(*counts premises in a rule*)
fun nprems_of (Thm {prop, ...}) =
Logic.count_prems (prop, 0);
fun major_prem_of thm =
(case prems_of thm of
prem :: _ => Logic.strip_assums_concl prem
| [] => raise THM ("major_prem_of: rule with no premises", 0, [thm]));
fun no_prems thm = nprems_of thm = 0;
(*maps object-rule to conclusion*)
fun concl_of (Thm {prop, ...}) = Logic.strip_imp_concl prop;
(*the statement of any thm is a cterm*)
fun cprop_of (Thm {sign_ref, maxidx, prop, ...}) =
Cterm {sign_ref = sign_ref, maxidx = maxidx, T = propT, t = prop};
(** sort contexts of theorems **)
(* basic utils *)
(*accumulate sorts suppressing duplicates; these are coded low levelly
to improve efficiency a bit*)
fun add_typ_sorts (Type (_, Ts), Ss) = add_typs_sorts (Ts, Ss)
| add_typ_sorts (TFree (_, S), Ss) = Sorts.ins_sort(S,Ss)
| add_typ_sorts (TVar (_, S), Ss) = Sorts.ins_sort(S,Ss)
and add_typs_sorts ([], Ss) = Ss
| add_typs_sorts (T :: Ts, Ss) = add_typs_sorts (Ts, add_typ_sorts (T, Ss));
fun add_term_sorts (Const (_, T), Ss) = add_typ_sorts (T, Ss)
| add_term_sorts (Free (_, T), Ss) = add_typ_sorts (T, Ss)
| add_term_sorts (Var (_, T), Ss) = add_typ_sorts (T, Ss)
| add_term_sorts (Bound _, Ss) = Ss
| add_term_sorts (Abs (_,T,t), Ss) = add_term_sorts (t, add_typ_sorts (T,Ss))
| add_term_sorts (t $ u, Ss) = add_term_sorts (t, add_term_sorts (u, Ss));
fun add_terms_sorts ([], Ss) = Ss
| add_terms_sorts (t::ts, Ss) = add_terms_sorts (ts, add_term_sorts (t,Ss));
fun env_codT (Envir.Envir {iTs, ...}) = map snd (Vartab.dest iTs);
fun add_env_sorts (Envir.Envir {iTs, asol, ...}, Ss) =
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, tpairs, prop, ...}, Ss) =
add_terms_sorts (hyps @ terms_of_tpairs tpairs, add_term_sorts (prop, Ss));
fun add_thms_shyps ([], Ss) = Ss
| add_thms_shyps (Thm {shyps, ...} :: ths, Ss) =
add_thms_shyps (ths, Sorts.union_sort (shyps, Ss));
(*get 'dangling' sort constraints of a thm*)
fun extra_shyps (th as Thm {shyps, ...}) =
Sorts.rems_sort (shyps, add_thm_sorts (th, []));
(* fix_shyps *)
fun all_sorts_nonempty sign_ref = isSome (Sign.universal_witness (Sign.deref sign_ref));
(*preserve sort contexts of rule premises and substituted types*)
fun fix_shyps thms Ts (thm as Thm {sign_ref, der, maxidx, hyps, tpairs, prop, ...}) =
Thm
{sign_ref = sign_ref,
der = der, (*no new derivation, as other rules call this*)
maxidx = maxidx,
shyps =
if all_sorts_nonempty sign_ref then []
else add_thm_sorts (thm, add_typs_sorts (Ts, add_thms_shyps (thms, []))),
hyps = hyps, tpairs = tpairs, prop = prop}
(* strip_shyps *)
(*remove extra sorts that are non-empty by virtue of type signature information*)
fun strip_shyps (thm as Thm {shyps = [], ...}) = thm
| strip_shyps (thm as Thm {sign_ref, der, maxidx, shyps, hyps, tpairs, prop}) =
let
val sign = Sign.deref sign_ref;
val present_sorts = add_thm_sorts (thm, []);
val extra_shyps = Sorts.rems_sort (shyps, present_sorts);
val witnessed_shyps = Sign.witness_sorts sign present_sorts extra_shyps;
in
Thm {sign_ref = sign_ref, der = der, maxidx = maxidx,
shyps = Sorts.rems_sort (shyps, map #2 witnessed_shyps),
hyps = hyps, tpairs = tpairs, prop = prop}
end;
(** Axioms **)
(*look up the named axiom in the theory*)
fun get_axiom_i theory name =
let
fun get_ax [] = NONE
| get_ax (thy :: thys) =
let val {sign, axioms, ...} = Theory.rep_theory thy in
(case Symtab.lookup (axioms, name) of
SOME t =>
SOME (fix_shyps [] []
(Thm {sign_ref = Sign.self_ref sign,
der = Pt.infer_derivs' I
(false, Pt.axm_proof name t),
maxidx = maxidx_of_term t,
shyps = [],
hyps = [],
tpairs = [],
prop = t}))
| NONE => get_ax thys)
end;
in
(case get_ax (theory :: Theory.ancestors_of theory) of
SOME thm => thm
| NONE => raise THEORY ("No axiom " ^ quote name, [theory]))
end;
fun get_axiom thy = get_axiom_i thy o Sign.intern (Theory.sign_of thy) Theory.axiomK;
fun def_name name = name ^ "_def";
fun get_def thy = get_axiom thy o def_name;
(*return additional axioms of this theory node*)
fun axioms_of thy =
map (fn (s, _) => (s, get_axiom thy s))
(Symtab.dest (#axioms (Theory.rep_theory thy)));
(* name and tags -- make proof objects more readable *)
fun get_name_tags (Thm {hyps, prop, der = (_, prf), ...}) =
Pt.get_name_tags hyps prop prf;
fun put_name_tags x (Thm {sign_ref, der = (ora, prf), maxidx,
shyps, hyps, tpairs = [], prop}) = Thm {sign_ref = sign_ref,
der = (ora, Pt.thm_proof (Sign.deref sign_ref) x hyps prop prf),
maxidx = maxidx, shyps = shyps, hyps = hyps, tpairs = [], prop = prop}
| put_name_tags _ thm =
raise THM ("put_name_tags: unsolved flex-flex constraints", 0, [thm]);
val name_of_thm = #1 o get_name_tags;
val tags_of_thm = #2 o get_name_tags;
fun name_thm (name, thm) = put_name_tags (name, tags_of_thm thm) thm;
(*Compression of theorems -- a separate rule, not integrated with the others,
as it could be slow.*)
fun compress (Thm {sign_ref, der, maxidx, shyps, hyps, tpairs, prop}) =
Thm {sign_ref = sign_ref,
der = der, (*No derivation recorded!*)
maxidx = maxidx,
shyps = shyps,
hyps = map Term.compress_term hyps,
tpairs = map (pairself Term.compress_term) tpairs,
prop = Term.compress_term prop};
(*** Meta rules ***)
(*Check that term does not contain same var with different typing/sorting.
If this check must be made, recalculate maxidx in hope of preventing its
recurrence.*)
fun nodup_vars (thm as Thm{sign_ref, der, maxidx, shyps, hyps, tpairs, prop}) s =
let
val prop' = attach_tpairs tpairs prop;
val _ = Sign.nodup_vars prop'
in Thm {sign_ref = sign_ref,
der = der,
maxidx = maxidx_of_term prop',
shyps = shyps,
hyps = hyps,
tpairs = tpairs,
prop = prop}
end handle TYPE(msg,Ts,ts) => raise TYPE(s^": "^msg,Ts,ts);
(** 'primitive' rules **)
(*discharge all assumptions t from ts*)
val disch = gen_rem (op aconv);
(*The assumption rule A|-A in a theory*)
fun assume raw_ct : thm =
let val ct as Cterm {sign_ref, t=prop, T, maxidx} = adjust_maxidx raw_ct
in if T<>propT then
raise THM("assume: assumptions must have type prop", 0, [])
else if maxidx <> ~1 then
raise THM("assume: assumptions may not contain scheme variables",
maxidx, [])
else Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' I (false, Pt.Hyp prop),
maxidx = ~1,
shyps = add_term_sorts(prop,[]),
hyps = [prop],
tpairs = [],
prop = prop}
end;
(*Implication introduction
[A]
:
B
-------
A ==> B
*)
fun implies_intr cA (thB as Thm{sign_ref,der,maxidx,hyps,shyps,tpairs,prop}) : thm =
let val Cterm {sign_ref=sign_refA, t=A, T, maxidx=maxidxA} = cA
in if T<>propT then
raise THM("implies_intr: assumptions must have type prop", 0, [thB])
else
Thm{sign_ref = Sign.merge_refs (sign_ref,sign_refA),
der = Pt.infer_derivs' (Pt.implies_intr_proof A) der,
maxidx = Int.max(maxidxA, maxidx),
shyps = add_term_sorts (A, shyps),
hyps = disch(hyps,A),
tpairs = tpairs,
prop = implies$A$prop}
handle TERM _ =>
raise THM("implies_intr: incompatible signatures", 0, [thB])
end;
(*Implication elimination
A ==> B A
------------
B
*)
fun implies_elim thAB thA : thm =
let val Thm{maxidx=maxA, der=derA, hyps=hypsA, shyps=shypsA, tpairs=tpairsA, prop=propA, ...} = thA
and Thm{der, maxidx, hyps, shyps, tpairs, prop, ...} = thAB;
fun err(a) = raise THM("implies_elim: "^a, 0, [thAB,thA])
in case prop of
imp$A$B =>
if imp=implies andalso A aconv propA
then
Thm{sign_ref= merge_thm_sgs(thAB,thA),
der = Pt.infer_derivs (curry Pt.%%) der derA,
maxidx = Int.max(maxA,maxidx),
shyps = Sorts.union_sort (shypsA, shyps),
hyps = union_term(hypsA,hyps), (*dups suppressed*)
tpairs = tpairsA @ tpairs,
prop = B}
else err("major premise")
| _ => err("major premise")
end;
(*Forall introduction. The Free or Var x must not be free in the hypotheses.
A
-----
!!x.A
*)
fun forall_intr cx (th as Thm{sign_ref,der,maxidx,hyps,tpairs,prop,...}) =
let val x = term_of cx;
fun result a T = fix_shyps [th] []
(Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.forall_intr_proof x a) der,
maxidx = maxidx,
shyps = [],
hyps = hyps,
tpairs = tpairs,
prop = all(T) $ Abs(a, T, abstract_over (x,prop))})
fun check_occs x ts =
if exists (apl(x, Logic.occs)) ts
then raise THM("forall_intr: variable free in assumptions", 0, [th])
else ()
in case x of
Free(a,T) => (check_occs x (hyps @ terms_of_tpairs tpairs); result a T)
| Var((a,_),T) => (check_occs x (terms_of_tpairs tpairs); result a T)
| _ => raise THM("forall_intr: not a variable", 0, [th])
end;
(*Forall elimination
!!x.A
------
A[t/x]
*)
fun forall_elim ct (th as Thm{sign_ref,der,maxidx,hyps,tpairs,prop,...}) : thm =
let val Cterm {sign_ref=sign_reft, t, T, maxidx=maxt} = ct
in case prop of
Const("all",Type("fun",[Type("fun",[qary,_]),_])) $ A =>
if T<>qary then
raise THM("forall_elim: type mismatch", 0, [th])
else let val thm = fix_shyps [th] []
(Thm{sign_ref= Sign.merge_refs(sign_ref,sign_reft),
der = Pt.infer_derivs' (Pt.% o rpair (SOME t)) der,
maxidx = Int.max(maxidx, maxt),
shyps = [],
hyps = hyps,
tpairs = tpairs,
prop = betapply(A,t)})
in if maxt >= 0 andalso maxidx >= 0
then nodup_vars thm "forall_elim"
else thm (*no new Vars: no expensive check!*)
end
| _ => raise THM("forall_elim: not quantified", 0, [th])
end
handle TERM _ =>
raise THM("forall_elim: incompatible signatures", 0, [th]);
(* Equality *)
(*The reflexivity rule: maps t to the theorem t==t *)
fun reflexive ct =
let val Cterm {sign_ref, t, T, maxidx} = ct
in Thm{sign_ref= sign_ref,
der = Pt.infer_derivs' I (false, Pt.reflexive),
shyps = add_term_sorts (t, []),
hyps = [],
maxidx = maxidx,
tpairs = [],
prop = Logic.mk_equals(t,t)}
end;
(*The symmetry rule
t==u
----
u==t
*)
fun symmetric (th as Thm{sign_ref,der,maxidx,shyps,hyps,tpairs,prop}) =
case prop of
(eq as Const("==", Type (_, [T, _]))) $ t $ u =>
(*no fix_shyps*)
Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' Pt.symmetric der,
maxidx = maxidx,
shyps = shyps,
hyps = hyps,
tpairs = tpairs,
prop = eq$u$t}
| _ => raise THM("symmetric", 0, [th]);
(*The transitive rule
t1==u u==t2
--------------
t1==t2
*)
fun transitive th1 th2 =
let val Thm{der=der1, maxidx=max1, hyps=hyps1, shyps=shyps1, tpairs=tpairs1, prop=prop1,...} = th1
and Thm{der=der2, maxidx=max2, hyps=hyps2, shyps=shyps2, tpairs=tpairs2, prop=prop2,...} = th2;
fun err(msg) = raise THM("transitive: "^msg, 0, [th1,th2])
in case (prop1,prop2) of
((eq as Const("==", Type (_, [T, _]))) $ t1 $ u, Const("==",_) $ u' $ t2) =>
if not (u aconv u') then err"middle term"
else let val thm =
Thm{sign_ref= merge_thm_sgs(th1,th2),
der = Pt.infer_derivs (Pt.transitive u T) der1 der2,
maxidx = Int.max(max1,max2),
shyps = Sorts.union_sort (shyps1, shyps2),
hyps = union_term(hyps1,hyps2),
tpairs = tpairs1 @ tpairs2,
prop = eq$t1$t2}
in if max1 >= 0 andalso max2 >= 0
then nodup_vars thm "transitive"
else thm (*no new Vars: no expensive check!*)
end
| _ => err"premises"
end;
(*Beta-conversion: maps (%x.t)(u) to the theorem (%x.t)(u) == t[u/x]
Fully beta-reduces the term if full=true
*)
fun beta_conversion full ct =
let val Cterm {sign_ref, t, T, maxidx} = ct
in Thm
{sign_ref = sign_ref,
der = Pt.infer_derivs' I (false, Pt.reflexive),
maxidx = maxidx,
shyps = add_term_sorts (t, []),
hyps = [],
tpairs = [],
prop = Logic.mk_equals (t, if full then Envir.beta_norm 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 Thm
{sign_ref = sign_ref,
der = Pt.infer_derivs' I (false, Pt.reflexive),
maxidx = maxidx,
shyps = add_term_sorts (t, []),
hyps = [],
tpairs = [],
prop = Logic.mk_equals (t, Pattern.eta_contract t)}
end;
(*The abstraction rule. The Free or Var x must not be free in the hypotheses.
The bound variable will be named "a" (since x will be something like x320)
t == u
------------
%x.t == %x.u
*)
fun abstract_rule a cx (th as Thm{sign_ref,der,maxidx,hyps,shyps,tpairs,prop}) =
let val x = term_of cx;
val (t,u) = Logic.dest_equals prop
handle TERM _ =>
raise THM("abstract_rule: premise not an equality", 0, [th])
fun result T =
Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.abstract_rule x a) der,
maxidx = maxidx,
shyps = add_typ_sorts (T, shyps),
hyps = hyps,
tpairs = tpairs,
prop = Logic.mk_equals(Abs(a, T, abstract_over (x,t)),
Abs(a, T, abstract_over (x,u)))}
fun check_occs x ts =
if exists (apl(x, Logic.occs)) ts
then raise THM("abstract_rule: variable free in assumptions", 0, [th])
else ()
in case x of
Free(_,T) => (check_occs x (hyps @ terms_of_tpairs tpairs); result T)
| Var(_,T) => (check_occs x (terms_of_tpairs tpairs); result T)
| _ => raise THM("abstract_rule: not a variable", 0, [th])
end;
(*The combination rule
f == g t == u
--------------
f(t) == g(u)
*)
fun combination th1 th2 =
let val Thm{der=der1, maxidx=max1, shyps=shyps1, hyps=hyps1,
tpairs=tpairs1, prop=prop1,...} = th1
and Thm{der=der2, maxidx=max2, shyps=shyps2, hyps=hyps2,
tpairs=tpairs2, prop=prop2,...} = th2
fun chktypes fT tT =
(case fT of
Type("fun",[T1,T2]) =>
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 ("==", 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 = Pt.infer_derivs
(Pt.combination f g t u fT) der1 der2,
maxidx = Int.max(max1,max2),
shyps = Sorts.union_sort(shyps1,shyps2),
hyps = union_term(hyps1,hyps2),
tpairs = tpairs1 @ tpairs2,
prop = Logic.mk_equals(f$t, g$u)}
in if max1 >= 0 andalso max2 >= 0
then nodup_vars thm "combination"
else thm (*no new Vars: no expensive check!*)
end
| _ => raise THM("combination: premises", 0, [th1,th2])
end;
(* Equality introduction
A ==> B B ==> A
----------------
A == B
*)
fun equal_intr th1 th2 =
let val Thm{der=der1, maxidx=max1, shyps=shyps1, hyps=hyps1,
tpairs=tpairs1, prop=prop1,...} = th1
and Thm{der=der2, maxidx=max2, shyps=shyps2, hyps=hyps2,
tpairs=tpairs2, prop=prop2,...} = th2;
fun err(msg) = raise THM("equal_intr: "^msg, 0, [th1,th2])
in case (prop1,prop2) of
(Const("==>",_) $ A $ B, Const("==>",_) $ B' $ A') =>
if A aconv A' andalso B aconv B'
then
(*no fix_shyps*)
Thm{sign_ref = merge_thm_sgs(th1,th2),
der = Pt.infer_derivs (Pt.equal_intr A B) der1 der2,
maxidx = Int.max(max1,max2),
shyps = Sorts.union_sort(shyps1,shyps2),
hyps = union_term(hyps1,hyps2),
tpairs = tpairs1 @ tpairs2,
prop = Logic.mk_equals(A,B)}
else err"not equal"
| _ => err"premises"
end;
(*The equal propositions rule
A == B A
---------
B
*)
fun equal_elim th1 th2 =
let val Thm{der=der1, maxidx=max1, hyps=hyps1, tpairs=tpairs1, prop=prop1,...} = th1
and Thm{der=der2, maxidx=max2, hyps=hyps2, tpairs=tpairs2, prop=prop2,...} = th2;
fun err(msg) = raise THM("equal_elim: "^msg, 0, [th1,th2])
in case prop1 of
Const("==",_) $ A $ B =>
if not (prop2 aconv A) then err"not equal" else
fix_shyps [th1, th2] []
(Thm{sign_ref= merge_thm_sgs(th1,th2),
der = Pt.infer_derivs (Pt.equal_elim A B) der1 der2,
maxidx = Int.max(max1,max2),
shyps = [],
hyps = union_term(hyps1,hyps2),
tpairs = tpairs1 @ tpairs2,
prop = B})
| _ => err"major premise"
end;
(**** Derived rules ****)
(*Discharge all hypotheses. Need not verify cterms or call fix_shyps.
Repeated hypotheses are discharged only once; fold cannot do this*)
fun implies_intr_hyps (Thm{sign_ref, der, maxidx, shyps, hyps=A::As, tpairs, prop}) =
implies_intr_hyps (*no fix_shyps*)
(Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.implies_intr_proof A) der,
maxidx = maxidx,
shyps = shyps,
hyps = disch(As,A),
tpairs = tpairs,
prop = implies$A$prop})
| implies_intr_hyps th = th;
(*Smash" unifies the list of term pairs leaving no flex-flex pairs.
Instantiates the theorem and deletes trivial tpairs.
Resulting sequence may contain multiple elements if the tpairs are
not all flex-flex. *)
fun flexflex_rule (th as Thm{sign_ref, der, maxidx, hyps, tpairs, prop, ...}) =
let fun newthm env =
if Envir.is_empty env then th
else
let val ntpairs = map (pairself (Envir.norm_term env)) tpairs;
val newprop = Envir.norm_term env prop;
(*Remove trivial tpairs, of the form t=t*)
val distpairs = List.filter (not o op aconv) ntpairs
in fix_shyps [th] (env_codT env)
(Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.norm_proof' env) der,
maxidx = maxidx_of_terms (newprop ::
terms_of_tpairs distpairs),
shyps = [],
hyps = hyps,
tpairs = distpairs,
prop = newprop})
end;
in Seq.map newthm
(Unify.smash_unifiers(Sign.deref sign_ref, Envir.empty maxidx, tpairs))
end;
(*Instantiation of Vars
A
-------------------
A[t1/v1,....,tn/vn]
*)
local
(*Check that all the terms are Vars and are distinct*)
fun instl_ok ts = forall is_Var ts andalso null(findrep ts);
fun prt_typing sg_ref t T =
let val sg = Sign.deref sg_ref in
Pretty.block [Sign.pretty_term sg t, Pretty.str " ::", Pretty.brk 1, Sign.pretty_typ sg T]
end;
(*For instantiate: process pair of cterms, merge theories*)
fun add_ctpair ((ct,cu), (sign_ref,tpairs)) =
let
val Cterm {sign_ref=sign_reft, t=t, T= T, ...} = ct
and Cterm {sign_ref=sign_refu, t=u, T= U, ...} = cu;
val sign_ref_merged = Sign.merge_refs (sign_ref, Sign.merge_refs (sign_reft, sign_refu));
in
if T=U then (sign_ref_merged, (t,u)::tpairs)
else raise TYPE (Pretty.string_of (Pretty.block [Pretty.str "instantiate: type conflict",
Pretty.fbrk, prt_typing sign_ref_merged t T,
Pretty.fbrk, prt_typing sign_ref_merged u U]), [T,U], [t,u])
end;
fun add_ctyp ((v,ctyp), (sign_ref',vTs)) =
let val Ctyp {T,sign_ref} = ctyp
in (Sign.merge_refs(sign_ref,sign_ref'), (v,T)::vTs) end;
in
(*Left-to-right replacements: ctpairs = [...,(vi,ti),...].
Instantiates distinct Vars by terms of same type.
No longer normalizes the new theorem! *)
fun instantiate ([], []) th = th
| instantiate (vcTs,ctpairs) (th as Thm{sign_ref,der,maxidx,hyps,shyps,tpairs=dpairs,prop}) =
let val (newsign_ref,tpairs) = foldr add_ctpair (sign_ref,[]) ctpairs;
val (newsign_ref,vTs) = foldr add_ctyp (newsign_ref,[]) vcTs;
fun subst t =
subst_atomic tpairs (Sign.inst_term_tvars (Sign.deref newsign_ref) vTs t);
val newprop = subst prop;
val newdpairs = map (pairself subst) dpairs;
val newth =
(Thm{sign_ref = newsign_ref,
der = Pt.infer_derivs' (Pt.instantiate vTs tpairs) der,
maxidx = maxidx_of_terms (newprop ::
terms_of_tpairs newdpairs),
shyps = add_insts_sorts ((vTs, tpairs), shyps),
hyps = hyps,
tpairs = newdpairs,
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)))
then raise THM("instantiate: type variables not distinct", 0, [th])
else nodup_vars newth "instantiate"
end
handle TERM _ => raise THM("instantiate: incompatible signatures", 0, [th])
| TYPE (msg, _, _) => raise THM (msg, 0, [th]);
end;
(*The trivial implication A==>A, justified by assume and forall rules.
A can contain Vars, not so for assume! *)
fun trivial ct : thm =
let val Cterm {sign_ref, t=A, T, maxidx} = ct
in if T<>propT then
raise THM("trivial: the term must have type prop", 0, [])
else fix_shyps [] []
(Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' I (false, Pt.AbsP ("H", NONE, Pt.PBound 0)),
maxidx = maxidx,
shyps = [],
hyps = [],
tpairs = [],
prop = implies$A$A})
end;
(*Axiom-scheme reflecting signature contents: "OFCLASS(?'a::c, c_class)" *)
fun class_triv sign c =
let val Cterm {sign_ref, t, maxidx, ...} =
cterm_of sign (Logic.mk_inclass (TVar (("'a", 0), [c]), c))
handle TERM (msg, _) => raise THM ("class_triv: " ^ msg, 0, []);
in
fix_shyps [] []
(Thm {sign_ref = sign_ref,
der = Pt.infer_derivs' I
(false, Pt.PAxm ("ProtoPure.class_triv:" ^ c, t, SOME [])),
maxidx = maxidx,
shyps = [],
hyps = [],
tpairs = [],
prop = t})
end;
(* Replace all TFrees not fixed or in the hyps by new TVars *)
fun varifyT' fixed (Thm{sign_ref,der,maxidx,shyps,hyps,tpairs,prop}) =
let
val tfrees = foldr add_term_tfree_names fixed hyps;
val prop1 = attach_tpairs tpairs prop;
val (prop2, al) = Type.varify (prop1, tfrees);
val (ts, prop3) = Logic.strip_prems (length tpairs, [], prop2)
in let val thm = (*no fix_shyps*)
Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.varify_proof prop tfrees) der,
maxidx = Int.max(0,maxidx),
shyps = shyps,
hyps = hyps,
tpairs = rev (map Logic.dest_equals ts),
prop = prop3}
in (nodup_vars thm "varifyT", al) end
(* this nodup_vars check can be removed if thms are guaranteed not to contain
duplicate TVars with different sorts *)
end;
val varifyT = #1 o varifyT' [];
(* Replace all TVars by new TFrees *)
fun freezeT(Thm{sign_ref,der,maxidx,shyps,hyps,tpairs,prop}) =
let
val prop1 = attach_tpairs tpairs prop;
val (prop2, _) = Type.freeze_thaw prop1;
val (ts, prop3) = Logic.strip_prems (length tpairs, [], prop2)
in (*no fix_shyps*)
Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.freezeT prop1) der,
maxidx = maxidx_of_term prop2,
shyps = shyps,
hyps = hyps,
tpairs = rev (map Logic.dest_equals ts),
prop = prop3}
end;
(*** Inference rules for tactics ***)
(*Destruct proof state into constraints, other goals, goal(i), rest *)
fun dest_state (state as Thm{prop,tpairs,...}, i) =
(case Logic.strip_prems(i, [], prop) of
(B::rBs, C) => (tpairs, rev rBs, B, C)
| _ => raise THM("dest_state", i, [state]))
handle TERM _ => raise THM("dest_state", i, [state]);
(*Increment variables and parameters of orule as required for
resolution with goal i of state. *)
fun lift_rule (state, i) orule =
let val Thm{shyps=sshyps, prop=sprop, maxidx=smax, sign_ref=ssign_ref,...} = state
val (Bi::_, _) = Logic.strip_prems(i, [], sprop)
handle TERM _ => raise THM("lift_rule", i, [orule,state])
val ct_Bi = Cterm {sign_ref=ssign_ref, maxidx=smax, T=propT, t=Bi}
val (lift_abs,lift_all) = Logic.lift_fns(Bi,smax+1)
val (Thm{sign_ref, der, maxidx,shyps,hyps,tpairs,prop}) = orule
val (As, B) = Logic.strip_horn prop
in (*no fix_shyps*)
Thm{sign_ref = merge_thm_sgs(state,orule),
der = Pt.infer_derivs' (Pt.lift_proof Bi (smax+1) prop) der,
maxidx = maxidx+smax+1,
shyps = Sorts.union_sort(sshyps,shyps),
hyps = hyps,
tpairs = map (pairself lift_abs) tpairs,
prop = Logic.list_implies (map lift_all As, lift_all B)}
end;
fun incr_indexes i (thm as Thm {sign_ref, der, maxidx, shyps, hyps, tpairs, prop}) =
if i < 0 then raise THM ("negative increment", 0, [thm]) else
if i = 0 then thm else
Thm {sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.map_proof_terms
(Logic.incr_indexes ([], i)) (incr_tvar i)) der,
maxidx = maxidx + i,
shyps = shyps,
hyps = hyps,
tpairs = map (pairself (Logic.incr_indexes ([], i))) tpairs,
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;
val (tpairs, Bs, Bi, C) = dest_state(state,i)
fun newth n (env as Envir.Envir{maxidx, ...}, tpairs) =
fix_shyps [state] (env_codT env)
(Thm{sign_ref = sign_ref,
der = Pt.infer_derivs'
((if Envir.is_empty env then I else (Pt.norm_proof' env)) o
Pt.assumption_proof Bs Bi n) der,
maxidx = maxidx,
shyps = [],
hyps = hyps,
tpairs = if Envir.is_empty env then tpairs else
map (pairself (Envir.norm_term env)) tpairs,
prop =
if Envir.is_empty env then (*avoid wasted normalizations*)
Logic.list_implies (Bs, C)
else (*normalize the new rule fully*)
Envir.norm_term env (Logic.list_implies (Bs, C))});
fun addprfs [] _ = Seq.empty
| addprfs ((t,u)::apairs) n = Seq.make (fn()=> Seq.pull
(Seq.mapp (newth n)
(Unify.unifiers(Sign.deref sign_ref,Envir.empty maxidx, (t,u)::tpairs))
(addprfs apairs (n+1))))
in addprfs (Logic.assum_pairs (~1,Bi)) 1 end;
(*Solve subgoal Bi of proof state B1...Bn/C by assumption.
Checks if Bi's conclusion is alpha-convertible to one of its assumptions*)
fun eq_assumption i state =
let val Thm{sign_ref,der,maxidx,hyps,prop,...} = state;
val (tpairs, Bs, Bi, C) = dest_state(state,i)
in (case find_index (op aconv) (Logic.assum_pairs (~1,Bi)) of
(~1) => raise THM("eq_assumption", 0, [state])
| n => fix_shyps [state] []
(Thm{sign_ref = sign_ref,
der = Pt.infer_derivs'
(Pt.assumption_proof Bs Bi (n+1)) der,
maxidx = maxidx,
shyps = [],
hyps = hyps,
tpairs = tpairs,
prop = Logic.list_implies (Bs, C)}))
end;
(*For rotate_tac: fast rotation of assumptions of subgoal i*)
fun rotate_rule k i state =
let val Thm{sign_ref,der,maxidx,hyps,prop,shyps,...} = state;
val (tpairs, Bs, Bi, C) = dest_state(state,i)
val params = Term.strip_all_vars Bi
and rest = Term.strip_all_body Bi
val asms = Logic.strip_imp_prems rest
and concl = Logic.strip_imp_concl rest
val n = length asms
val m = if k<0 then n+k else k
val Bi' = if 0=m orelse m=n then Bi
else if 0<m andalso m<n
then let val (ps,qs) = splitAt(m,asms)
in list_all(params, Logic.list_implies(qs @ ps, concl))
end
else raise THM("rotate_rule", k, [state])
in (*no fix_shyps*)
Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.rotate_proof Bs Bi m) der,
maxidx = maxidx,
shyps = shyps,
hyps = hyps,
tpairs = tpairs,
prop = Logic.list_implies (Bs @ [Bi'], C)}
end;
(*Rotates a rule's premises to the left by k, leaving the first j premises
unchanged. Does nothing if k=0 or if k equals n-j, where n is the
number of premises. Useful with etac and underlies tactic/defer_tac*)
fun permute_prems j k rl =
let val Thm{sign_ref,der,maxidx,hyps,tpairs,prop,shyps} = rl
val prems = Logic.strip_imp_prems prop
and concl = Logic.strip_imp_concl prop
val moved_prems = List.drop(prems, j)
and fixed_prems = List.take(prems, j)
handle Subscript => raise THM("permute_prems:j", j, [rl])
val n_j = length moved_prems
val m = if k<0 then n_j + k else k
val prop' = if 0 = m orelse m = n_j then prop
else if 0<m andalso m<n_j
then let val (ps,qs) = splitAt(m,moved_prems)
in Logic.list_implies(fixed_prems @ qs @ ps, concl) end
else raise THM("permute_prems:k", k, [rl])
in (*no fix_shyps*)
Thm{sign_ref = sign_ref,
der = Pt.infer_derivs' (Pt.permute_prems_prf prems j m) der,
maxidx = maxidx,
shyps = shyps,
hyps = hyps,
tpairs = tpairs,
prop = prop'}
end;
(** User renaming of parameters in a subgoal **)
(*Calls error rather than raising an exception because it is intended
for top-level use -- exception handling would not make sense here.
The names in cs, if distinct, are used for the innermost parameters;
preceding parameters may be renamed to make all params distinct.*)
fun rename_params_rule (cs, i) state =
let val Thm{sign_ref,der,maxidx,hyps,shyps,...} = state
val (tpairs, Bs, Bi, C) = dest_state(state,i)
val iparams = map #1 (Logic.strip_params Bi)
val short = length iparams - length cs
val newnames =
if short<0 then error"More names than abstractions!"
else variantlist(Library.take (short,iparams), cs) @ cs
val freenames = map (#1 o dest_Free) (term_frees Bi)
val newBi = Logic.list_rename_params (newnames, Bi)
in
case findrep cs of
c::_ => (warning ("Can't rename. Bound variables not distinct: " ^ c);
state)
| [] => (case cs inter_string freenames of
a::_ => (warning ("Can't rename. Bound/Free variable clash: " ^ a);
state)
| [] => Thm{sign_ref = sign_ref,
der = der,
maxidx = maxidx,
shyps = shyps,
hyps = hyps,
tpairs = tpairs,
prop = Logic.list_implies (Bs @ [newBi], C)})
end;
(*** Preservation of bound variable names ***)
fun rename_boundvars pat obj (thm as Thm {sign_ref, der, maxidx, hyps, shyps, tpairs, prop}) =
(case Term.rename_abs pat obj prop of
NONE => thm
| SOME prop' => Thm
{sign_ref = sign_ref,
der = der,
maxidx = maxidx,
hyps = hyps,
shyps = shyps,
tpairs = tpairs,
prop = prop'});
(* strip_apply f A(,B) strips off all assumptions/parameters from A
introduced by lifting over B, and applies f to remaining part of A*)
fun strip_apply f =
let fun strip(Const("==>",_)$ A1 $ B1,
Const("==>",_)$ _ $ B2) = implies $ A1 $ strip(B1,B2)
| strip((c as Const("all",_)) $ Abs(a,T,t1),
Const("all",_) $ Abs(_,_,t2)) = c$Abs(a,T,strip(t1,t2))
| strip(A,_) = f A
in strip end;
(*Use the alist to rename all bound variables and some unknowns in a term
dpairs = current disagreement pairs; tpairs = permanent ones (flexflex);
Preserves unknowns in tpairs and on lhs of dpairs. *)
fun rename_bvs([],_,_,_) = I
| rename_bvs(al,dpairs,tpairs,B) =
let val vars = foldr add_term_vars []
(map fst dpairs @ map fst tpairs @ map snd tpairs)
(*unknowns appearing elsewhere be preserved!*)
val vids = map (#1 o #1 o dest_Var) vars;
fun rename(t as Var((x,i),T)) =
(case assoc(al,x) of
SOME(y) => if x mem_string vids orelse y mem_string vids then t
else Var((y,i),T)
| NONE=> t)
| rename(Abs(x,T,t)) =
Abs(getOpt(assoc_string(al,x),x), T, rename t)
| rename(f$t) = rename f $ rename t
| rename(t) = t;
fun strip_ren Ai = strip_apply rename (Ai,B)
in strip_ren end;
(*Function to rename bounds/unknowns in the argument, lifted over B*)
fun rename_bvars(dpairs, tpairs, B) =
rename_bvs(foldr Term.match_bvars [] dpairs, dpairs, tpairs, B);
(*** RESOLUTION ***)
(** Lifting optimizations **)
(*strip off pairs of assumptions/parameters in parallel -- they are
identical because of lifting*)
fun strip_assums2 (Const("==>", _) $ _ $ B1,
Const("==>", _) $ _ $ B2) = strip_assums2 (B1,B2)
| strip_assums2 (Const("all",_)$Abs(a,T,t1),
Const("all",_)$Abs(_,_,t2)) =
let val (B1,B2) = strip_assums2 (t1,t2)
in (Abs(a,T,B1), Abs(a,T,B2)) end
| strip_assums2 BB = BB;
(*Faster normalization: skip assumptions that were lifted over*)
fun norm_term_skip env 0 t = Envir.norm_term env t
| norm_term_skip env n (Const("all",_)$Abs(a,T,t)) =
let val Envir.Envir{iTs, ...} = env
val T' = typ_subst_TVars_Vartab iTs T
(*Must instantiate types of parameters because they are flattened;
this could be a NEW parameter*)
in all T' $ Abs(a, T', norm_term_skip env n t) end
| norm_term_skip env n (Const("==>", _) $ A $ B) =
implies $ A $ norm_term_skip env (n-1) B
| norm_term_skip env n t = error"norm_term_skip: too few assumptions??";
(*Composition of object rule r=(A1...Am/B) with proof state s=(B1...Bn/C)
Unifies B with Bi, replacing subgoal i (1 <= i <= n)
If match then forbid instantiations in proof state
If lifted then shorten the dpair using strip_assums2.
If eres_flg then simultaneously proves A1 by assumption.
nsubgoal is the number of new subgoals (written m above).
Curried so that resolution calls dest_state only once.
*)
local exception COMPOSE
in
fun bicompose_aux match (state, (stpairs, Bs, Bi, C), lifted)
(eres_flg, orule, nsubgoal) =
let val Thm{der=sder, maxidx=smax, shyps=sshyps, hyps=shyps, ...} = state
and Thm{der=rder, maxidx=rmax, shyps=rshyps, hyps=rhyps,
tpairs=rtpairs, prop=rprop,...} = orule
(*How many hyps to skip over during normalization*)
and nlift = Logic.count_prems(strip_all_body Bi,
if eres_flg then ~1 else 0)
val sign_ref = merge_thm_sgs(state,orule);
val sign = Sign.deref sign_ref;
(** Add new theorem with prop = '[| Bs; As |] ==> C' to thq **)
fun addth A (As, oldAs, rder', n) ((env as Envir.Envir {maxidx, ...}, tpairs), thq) =
let val normt = Envir.norm_term env;
(*perform minimal copying here by examining env*)
val (ntpairs, normp) =
if Envir.is_empty env then (tpairs, (Bs @ As, C))
else
let val ntps = map (pairself normt) tpairs
in if Envir.above (smax, env) then
(*no assignments in state; normalize the rule only*)
if lifted
then (ntps, (Bs @ map (norm_term_skip env nlift) As, C))
else (ntps, (Bs @ map normt As, C))
else if match then raise COMPOSE
else (*normalize the new rule fully*)
(ntps, (map normt (Bs @ As), normt C))
end
val th = (*tuned fix_shyps*)
Thm{sign_ref = sign_ref,
der = Pt.infer_derivs
((if Envir.is_empty env then I
else if Envir.above (smax, env) then
(fn f => fn der => f (Pt.norm_proof' env der))
else
curry op oo (Pt.norm_proof' env))
(Pt.bicompose_proof Bs oldAs As A n)) rder' sder,
maxidx = maxidx,
shyps = add_env_sorts (env, Sorts.union_sort(rshyps,sshyps)),
hyps = union_term(rhyps,shyps),
tpairs = ntpairs,
prop = Logic.list_implies normp}
in Seq.cons(th, thq) end handle COMPOSE => thq;
val (rAs,B) = Logic.strip_prems(nsubgoal, [], rprop)
handle TERM _ => raise THM("bicompose: rule", 0, [orule,state]);
(*Modify assumptions, deleting n-th if n>0 for e-resolution*)
fun newAs(As0, n, dpairs, tpairs) =
let val (As1, rder') =
if !Logic.auto_rename orelse not lifted then (As0, rder)
else (map (rename_bvars(dpairs,tpairs,B)) As0,
Pt.infer_derivs' (Pt.map_proof_terms
(rename_bvars (dpairs, tpairs, Bound 0)) I) rder);
in (map (Logic.flatten_params n) As1, As1, rder', n)
handle TERM _ =>
raise THM("bicompose: 1st premise", 0, [orule])
end;
val env = Envir.empty(Int.max(rmax,smax));
val BBi = if lifted then strip_assums2(B,Bi) else (B,Bi);
val dpairs = BBi :: (rtpairs@stpairs);
(*elim-resolution: try each assumption in turn. Initially n=1*)
fun tryasms (_, _, _, []) = Seq.empty
| tryasms (A, As, n, (t,u)::apairs) =
(case Seq.pull(Unify.unifiers(sign, env, (t,u)::dpairs)) of
NONE => tryasms (A, As, n+1, apairs)
| cell as SOME((_,tpairs),_) =>
Seq.it_right (addth A (newAs(As, n, [BBi,(u,t)], tpairs)))
(Seq.make(fn()=> cell),
Seq.make(fn()=> Seq.pull (tryasms(A, As, n+1, apairs)))))
fun eres [] = raise THM("bicompose: no premises", 0, [orule,state])
| eres (A1::As) = tryasms(SOME A1, As, 1, Logic.assum_pairs(nlift+1,A1))
(*ordinary resolution*)
fun res(NONE) = Seq.empty
| res(cell as SOME((_,tpairs),_)) =
Seq.it_right (addth NONE (newAs(rev rAs, 0, [BBi], tpairs)))
(Seq.make (fn()=> cell), Seq.empty)
in if eres_flg then eres(rev rAs)
else res(Seq.pull(Unify.unifiers(sign, env, dpairs)))
end;
end;
fun bicompose match arg i state =
bicompose_aux match (state, dest_state(state,i), false) arg;
(*Quick test whether rule is resolvable with the subgoal with hyps Hs
and conclusion B. If eres_flg then checks 1st premise of rule also*)
fun could_bires (Hs, B, eres_flg, rule) =
let fun could_reshyp (A1::_) = exists (apl(A1,could_unify)) Hs
| could_reshyp [] = false; (*no premise -- illegal*)
in could_unify(concl_of rule, B) andalso
(not eres_flg orelse could_reshyp (prems_of rule))
end;
(*Bi-resolution of a state with a list of (flag,rule) pairs.
Puts the rule above: rule/state. Renames vars in the rules. *)
fun biresolution match brules i state =
let val lift = lift_rule(state, i);
val (stpairs, Bs, Bi, C) = dest_state(state,i)
val B = Logic.strip_assums_concl Bi;
val Hs = Logic.strip_assums_hyp Bi;
val comp = bicompose_aux match (state, (stpairs, Bs, Bi, C), true);
fun res [] = Seq.empty
| res ((eres_flg, rule)::brules) =
if !Pattern.trace_unify_fail orelse
could_bires (Hs, B, eres_flg, rule)
then Seq.make (*delay processing remainder till needed*)
(fn()=> SOME(comp (eres_flg, lift rule, nprems_of rule),
res brules))
else res brules
in Seq.flat (res brules) end;
(*** Oracles ***)
fun invoke_oracle_i thy name =
let
val {sign = sg, oracles, ...} = Theory.rep_theory thy;
val oracle =
(case Symtab.lookup (oracles, name) of
NONE => raise THM ("Unknown oracle: " ^ name, 0, [])
| SOME (f, _) => f);
in
fn (sign, exn) =>
let
val sign_ref' = Sign.merge_refs (Sign.self_ref sg, Sign.self_ref sign);
val sign' = Sign.deref sign_ref';
val (prop, T, maxidx) =
Sign.certify_term (Sign.pp sign') sign' (oracle (sign', exn));
in
if T <> propT then
raise THM ("Oracle's result must have type prop: " ^ name, 0, [])
else fix_shyps [] []
(Thm {sign_ref = sign_ref',
der = (true, Pt.oracle_proof name prop),
maxidx = maxidx,
shyps = [],
hyps = [],
tpairs = [],
prop = prop})
end
end;
fun invoke_oracle thy =
invoke_oracle_i thy o Sign.intern (Theory.sign_of thy) Theory.oracleK;
end;
structure BasicThm: BASIC_THM = Thm;
open BasicThm;