(* Title: Pure/Isar/rule_insts.ML
Author: Makarius
Rule instantiations -- operations within a rule/subgoal context.
*)
signature BASIC_RULE_INSTS =
sig
val read_instantiate: Proof.context -> (indexname * string) list -> thm -> thm
val instantiate_tac: Proof.context -> (indexname * string) list -> tactic
val res_inst_tac: Proof.context -> (indexname * string) list -> thm -> int -> tactic
val eres_inst_tac: Proof.context -> (indexname * string) list -> thm -> int -> tactic
val cut_inst_tac: Proof.context -> (indexname * string) list -> thm -> int -> tactic
val forw_inst_tac: Proof.context -> (indexname * string) list -> thm -> int -> tactic
val dres_inst_tac: Proof.context -> (indexname * string) list -> thm -> int -> tactic
val thin_tac: Proof.context -> string -> int -> tactic
val subgoal_tac: Proof.context -> string -> int -> tactic
val method: (Proof.context -> (indexname * string) list -> thm -> int -> tactic) ->
(Proof.context -> thm list -> int -> tactic) -> (Proof.context -> Proof.method) context_parser
end;
signature RULE_INSTS =
sig
include BASIC_RULE_INSTS
val make_elim_preserve: thm -> thm
end;
structure Rule_Insts: RULE_INSTS =
struct
(** reading instantiations **)
local
fun error_var msg xi = error (msg ^ quote (Term.string_of_vname xi));
fun the_sort tvars (xi: indexname) =
(case AList.lookup (op =) tvars xi of
SOME S => S
| NONE => error_var "No such type variable in theorem: " xi);
fun the_type vars (xi: indexname) =
(case AList.lookup (op =) vars xi of
SOME T => T
| NONE => error_var "No such variable in theorem: " xi);
fun instantiate inst =
Term_Subst.instantiate ([], map (fn (xi, t) => ((xi, Term.fastype_of t), t)) inst) #>
Envir.beta_norm;
fun make_instT f v =
let
val T = TVar v;
val T' = f T;
in if T = T' then NONE else SOME (T, T') end;
fun make_inst f v =
let
val t = Var v;
val t' = f t;
in if t aconv t' then NONE else SOME (t, t') end;
val add_used =
(Thm.fold_terms o fold_types o fold_atyps)
(fn TFree (a, _) => insert (op =) a
| TVar ((a, _), _) => insert (op =) a
| _ => I);
in
fun read_termTs ctxt schematic ss Ts =
let
fun parse T = if T = propT then Syntax.parse_prop ctxt else Syntax.parse_term ctxt;
val ts = map2 parse Ts ss;
val ts' =
map2 (Type.constraint o Type_Infer.paramify_vars) Ts ts
|> Syntax.check_terms ((schematic ? Proof_Context.set_mode Proof_Context.mode_schematic) ctxt)
|> Variable.polymorphic ctxt;
val Ts' = map Term.fastype_of ts';
val tyenv = fold Type.raw_match (Ts ~~ Ts') Vartab.empty;
in (ts', map (apsnd snd) (Vartab.dest tyenv)) end;
fun read_insts ctxt mixed_insts (tvars, vars) =
let
val thy = Proof_Context.theory_of ctxt;
val cert = Thm.cterm_of thy;
val certT = Thm.ctyp_of thy;
val (type_insts, term_insts) = List.partition (String.isPrefix "'" o fst o fst) mixed_insts;
(* type instantiations *)
fun readT (xi, s) =
let
val S = the_sort tvars xi;
val T = Syntax.read_typ ctxt s;
in
if Sign.of_sort thy (T, S) then ((xi, S), T)
else error_var "Incompatible sort for typ instantiation of " xi
end;
val instT1 = Term_Subst.instantiateT (map readT type_insts);
val vars1 = map (apsnd instT1) vars;
(* term instantiations *)
val (xs, ss) = split_list term_insts;
val Ts = map (the_type vars1) xs;
val (ts, inferred) = read_termTs ctxt false ss Ts;
val instT2 = Term.typ_subst_TVars inferred;
val vars2 = map (apsnd instT2) vars1;
val inst2 = instantiate (xs ~~ ts);
(* result *)
val inst_tvars = map_filter (make_instT (instT2 o instT1)) tvars;
val inst_vars = map_filter (make_inst inst2) vars2;
in
(map (pairself certT) inst_tvars, map (pairself cert) inst_vars)
end;
fun read_instantiate_mixed ctxt mixed_insts thm =
let
val ctxt' = ctxt
|> Variable.declare_thm thm
|> fold (fn a => Variable.declare_names (Logic.mk_type (TFree (a, dummyS)))) (add_used thm []); (* FIXME !? *)
val tvars = Thm.fold_terms Term.add_tvars thm [];
val vars = Thm.fold_terms Term.add_vars thm [];
val insts = read_insts ctxt' mixed_insts (tvars, vars);
in
Drule.instantiate_normalize insts thm
|> Rule_Cases.save thm
end;
fun read_instantiate_mixed' ctxt (args, concl_args) thm =
let
fun zip_vars _ [] = []
| zip_vars (_ :: xs) (NONE :: rest) = zip_vars xs rest
| zip_vars ((x, _) :: xs) (SOME t :: rest) = (x, t) :: zip_vars xs rest
| zip_vars [] _ = error "More instantiations than variables in theorem";
val insts =
zip_vars (rev (Term.add_vars (Thm.full_prop_of thm) [])) args @
zip_vars (rev (Term.add_vars (Thm.concl_of thm) [])) concl_args;
in read_instantiate_mixed ctxt insts thm end;
end;
(* instantiation of rule or goal state *)
fun read_instantiate ctxt =
read_instantiate_mixed (ctxt |> Proof_Context.set_mode Proof_Context.mode_schematic); (* FIXME !? *)
fun instantiate_tac ctxt args = PRIMITIVE (read_instantiate ctxt args);
(** attributes **)
(* where: named instantiation *)
val _ = Context.>> (Context.map_theory
(Attrib.setup (Binding.name "where")
(Scan.lift (Parse.and_list (Args.var -- (Args.$$$ "=" |-- Args.name_source))) >>
(fn args =>
Thm.rule_attribute (fn context => read_instantiate_mixed (Context.proof_of context) args)))
"named instantiation of theorem"));
(* of: positional instantiation (terms only) *)
local
val inst = Args.maybe Args.name_source;
val concl = Args.$$$ "concl" -- Args.colon;
val insts =
Scan.repeat (Scan.unless concl inst) --
Scan.optional (concl |-- Scan.repeat inst) [];
in
val _ = Context.>> (Context.map_theory
(Attrib.setup (Binding.name "of")
(Scan.lift insts >> (fn args =>
Thm.rule_attribute (fn context => read_instantiate_mixed' (Context.proof_of context) args)))
"positional instantiation of theorem"));
end;
(** tactics **)
(* resolution after lifting and instantation; may refer to parameters of the subgoal *)
(* FIXME cleanup this mess!!! *)
fun bires_inst_tac bires_flag ctxt insts thm =
let
val thy = Proof_Context.theory_of ctxt;
(* Separate type and term insts *)
fun has_type_var ((x, _), _) =
(case Symbol.explode x of "'" :: _ => true | _ => false);
val Tinsts = filter has_type_var insts;
val tinsts = filter_out has_type_var insts;
(* Tactic *)
fun tac i st =
let
val (_, _, Bi, _) = Thm.dest_state (st, i);
val params = Logic.strip_params Bi; (*params of subgoal i as string typ pairs*)
val params = rev (Term.rename_wrt_term Bi params)
(*as they are printed: bound variables with*)
(*the same name are renamed during printing*)
val (param_names, ctxt') = ctxt
|> Variable.declare_thm thm
|> Thm.fold_terms Variable.declare_constraints st
|> Proof_Context.add_fixes (map (fn (x, T) => (Binding.name x, SOME T, NoSyn)) params);
(* Process type insts: Tinsts_env *)
fun absent xi = error
("No such variable in theorem: " ^ Term.string_of_vname xi);
val (rtypes, rsorts) = Drule.types_sorts thm;
fun readT (xi, s) =
let val S = case rsorts xi of SOME S => S | NONE => absent xi;
val T = Syntax.read_typ ctxt' s;
val U = TVar (xi, S);
in if Sign.typ_instance thy (T, U) then (U, T)
else error ("Instantiation of " ^ Term.string_of_vname xi ^ " fails")
end;
val Tinsts_env = map readT Tinsts;
(* Preprocess rule: extract vars and their types, apply Tinsts *)
fun get_typ xi =
(case rtypes xi of
SOME T => typ_subst_atomic Tinsts_env T
| NONE => absent xi);
val (xis, ss) = Library.split_list tinsts;
val Ts = map get_typ xis;
val (ts, envT) = read_termTs ctxt' true ss Ts;
val envT' = map (fn (ixn, T) =>
(TVar (ixn, the (rsorts ixn)), T)) envT @ Tinsts_env;
val cenv =
map
(fn (xi, t) =>
pairself (Thm.cterm_of thy) (Var (xi, fastype_of t), t))
(distinct
(fn ((x1, t1), (x2, t2)) => x1 = x2 andalso t1 aconv t2)
(xis ~~ ts));
(* Lift and instantiate rule *)
val maxidx = Thm.maxidx_of st;
val paramTs = map #2 params
and inc = maxidx+1
fun liftvar (Var ((a,j), T)) =
Var((a, j+inc), paramTs ---> Logic.incr_tvar inc T)
| liftvar t = raise TERM("Variable expected", [t]);
fun liftterm t =
fold_rev absfree (param_names ~~ paramTs) (Logic.incr_indexes (paramTs, inc) t);
fun liftpair (cv, ct) = (cterm_fun liftvar cv, cterm_fun liftterm ct);
val lifttvar = pairself (ctyp_of thy o Logic.incr_tvar inc);
val rule = Drule.instantiate_normalize
(map lifttvar envT', map liftpair cenv)
(Thm.lift_rule (Thm.cprem_of st i) thm)
in
if i > nprems_of st then no_tac st
else st |>
compose_tac (bires_flag, rule, nprems_of thm) i
end
handle TERM (msg,_) => (warning msg; no_tac st)
| THM (msg,_,_) => (warning msg; no_tac st);
in tac end;
val res_inst_tac = bires_inst_tac false;
val eres_inst_tac = bires_inst_tac true;
(* forward resolution *)
fun make_elim_preserve rl =
let
val cert = Thm.cterm_of (Thm.theory_of_thm rl);
val maxidx = Thm.maxidx_of rl;
fun cvar xi = cert (Var (xi, propT));
val revcut_rl' =
Drule.instantiate_normalize ([], [(cvar ("V", 0), cvar ("V", maxidx + 1)),
(cvar ("W", 0), cvar ("W", maxidx + 1))]) Drule.revcut_rl;
in
(case Seq.list_of (Thm.bicompose false (false, rl, Thm.nprems_of rl) 1 revcut_rl') of
[th] => th
| _ => raise THM ("make_elim_preserve", 1, [rl]))
end;
(*instantiate and cut -- for atomic fact*)
fun cut_inst_tac ctxt insts rule = res_inst_tac ctxt insts (make_elim_preserve rule);
(*forward tactic applies a rule to an assumption without deleting it*)
fun forw_inst_tac ctxt insts rule = cut_inst_tac ctxt insts rule THEN' assume_tac;
(*dresolve tactic applies a rule to replace an assumption*)
fun dres_inst_tac ctxt insts rule = eres_inst_tac ctxt insts (make_elim_preserve rule);
(* derived tactics *)
(*deletion of an assumption*)
fun thin_tac ctxt s = eres_inst_tac ctxt [(("V", 0), s)] Drule.thin_rl;
(*Introduce the given proposition as lemma and subgoal*)
fun subgoal_tac ctxt A = DETERM o res_inst_tac ctxt [(("psi", 0), A)] cut_rl;
(** methods **)
(* rule_tac etc. -- refer to dynamic goal state! *)
fun method inst_tac tac =
Args.goal_spec --
Scan.optional (Scan.lift
(Parse.and_list1 (Args.var -- (Args.$$$ "=" |-- Parse.!!! Args.name_source)) --|
Args.$$$ "in")) [] --
Attrib.thms >>
(fn ((quant, insts), thms) => fn ctxt => METHOD (fn facts =>
if null insts then quant (Method.insert_tac facts THEN' tac ctxt thms)
else
(case thms of
[thm] => quant (Method.insert_tac facts THEN' inst_tac ctxt insts thm)
| _ => error "Cannot have instantiations with multiple rules")));
val res_inst_meth = method res_inst_tac (K Tactic.resolve_tac);
val eres_inst_meth = method eres_inst_tac (K Tactic.eresolve_tac);
val cut_inst_meth = method cut_inst_tac (K Tactic.cut_rules_tac);
val dres_inst_meth = method dres_inst_tac (K Tactic.dresolve_tac);
val forw_inst_meth = method forw_inst_tac (K Tactic.forward_tac);
(* setup *)
val _ = Context.>> (Context.map_theory
(Method.setup (Binding.name "rule_tac") res_inst_meth "apply rule (dynamic instantiation)" #>
Method.setup (Binding.name "erule_tac") eres_inst_meth
"apply rule in elimination manner (dynamic instantiation)" #>
Method.setup (Binding.name "drule_tac") dres_inst_meth
"apply rule in destruct manner (dynamic instantiation)" #>
Method.setup (Binding.name "frule_tac") forw_inst_meth
"apply rule in forward manner (dynamic instantiation)" #>
Method.setup (Binding.name "cut_tac") cut_inst_meth "cut rule (dynamic instantiation)" #>
Method.setup (Binding.name "subgoal_tac")
(Args.goal_spec -- Scan.lift (Scan.repeat1 Args.name_source) >>
(fn (quant, props) => fn ctxt =>
SIMPLE_METHOD'' quant (EVERY' (map (subgoal_tac ctxt) props))))
"insert subgoal (dynamic instantiation)" #>
Method.setup (Binding.name "thin_tac")
(Args.goal_spec -- Scan.lift Args.name_source >>
(fn (quant, prop) => fn ctxt => SIMPLE_METHOD'' quant (thin_tac ctxt prop)))
"remove premise (dynamic instantiation)"));
end;
structure Basic_Rule_Insts: BASIC_RULE_INSTS = Rule_Insts;
open Basic_Rule_Insts;