wenzelm@16014: (*  Title:      Pure/simplifier.ML
wenzelm@16014:     ID:         $Id$
wenzelm@16014:     Author:     Tobias Nipkow and Markus Wenzel, TU Muenchen
wenzelm@16014: 
wenzelm@16014: Generic simplifier, suitable for most logics (see also
wenzelm@16014: meta_simplifier.ML for the actual meta-level rewriting engine).
wenzelm@16014: *)
wenzelm@16014: 
wenzelm@16014: signature BASIC_SIMPLIFIER =
wenzelm@16014: sig
wenzelm@16014:   include BASIC_META_SIMPLIFIER
wenzelm@17883:   val change_simpset: (simpset -> simpset) -> unit
wenzelm@16014:   val simpset_of: theory -> simpset
wenzelm@17883:   val simpset: unit -> simpset
wenzelm@16014:   val SIMPSET: (simpset -> tactic) -> tactic
wenzelm@16014:   val SIMPSET': (simpset -> 'a -> tactic) -> 'a -> tactic
wenzelm@16014:   val Addsimps: thm list -> unit
wenzelm@16014:   val Delsimps: thm list -> unit
wenzelm@16014:   val Addsimprocs: simproc list -> unit
wenzelm@16014:   val Delsimprocs: simproc list -> unit
wenzelm@16014:   val Addcongs: thm list -> unit
wenzelm@16014:   val Delcongs: thm list -> unit
wenzelm@16014:   val local_simpset_of: Proof.context -> simpset
wenzelm@17967:   val generic_simp_tac: bool -> bool * bool * bool -> simpset -> int -> tactic
wenzelm@16014:   val safe_asm_full_simp_tac: simpset -> int -> tactic
wenzelm@16014:   val               simp_tac: simpset -> int -> tactic
wenzelm@16014:   val           asm_simp_tac: simpset -> int -> tactic
wenzelm@16014:   val          full_simp_tac: simpset -> int -> tactic
wenzelm@16014:   val        asm_lr_simp_tac: simpset -> int -> tactic
wenzelm@16014:   val      asm_full_simp_tac: simpset -> int -> tactic
wenzelm@16014:   val               Simp_tac:            int -> tactic
wenzelm@16014:   val           Asm_simp_tac:            int -> tactic
wenzelm@16014:   val          Full_simp_tac:            int -> tactic
wenzelm@16014:   val        Asm_lr_simp_tac:            int -> tactic
wenzelm@16014:   val      Asm_full_simp_tac:            int -> tactic
wenzelm@16014:   val          simplify: simpset -> thm -> thm
wenzelm@16014:   val      asm_simplify: simpset -> thm -> thm
wenzelm@16014:   val     full_simplify: simpset -> thm -> thm
wenzelm@16014:   val   asm_lr_simplify: simpset -> thm -> thm
wenzelm@16014:   val asm_full_simplify: simpset -> thm -> thm
wenzelm@16014: end;
wenzelm@16014: 
wenzelm@16014: signature SIMPLIFIER =
wenzelm@16014: sig
wenzelm@16014:   include BASIC_SIMPLIFIER
wenzelm@17004:   val clear_ss: simpset -> simpset
wenzelm@17723:   val debug_bounds: bool ref
wenzelm@17883:   val inherit_context: simpset -> simpset -> simpset
wenzelm@17898:   val the_context: simpset -> Proof.context
wenzelm@17898:   val context: Proof.context -> simpset -> simpset
wenzelm@17898:   val theory_context: theory  -> simpset -> simpset
wenzelm@16458:   val simproc_i: theory -> string -> term list
wenzelm@16458:     -> (theory -> simpset -> term -> thm option) -> simproc
wenzelm@16458:   val simproc: theory -> string -> string list
wenzelm@16458:     -> (theory -> simpset -> term -> thm option) -> simproc
wenzelm@23598:   val          rewrite: simpset -> conv
wenzelm@23598:   val      asm_rewrite: simpset -> conv
wenzelm@23598:   val     full_rewrite: simpset -> conv
wenzelm@23598:   val   asm_lr_rewrite: simpset -> conv
wenzelm@23598:   val asm_full_rewrite: simpset -> conv
wenzelm@22379:   val get_ss: Context.generic -> simpset
wenzelm@22379:   val map_ss: (simpset -> simpset) -> Context.generic -> Context.generic
wenzelm@18728:   val attrib: (simpset * thm list -> simpset) -> attribute
wenzelm@18728:   val simp_add: attribute
wenzelm@18728:   val simp_del: attribute
wenzelm@18728:   val cong_add: attribute
wenzelm@18728:   val cong_del: attribute
wenzelm@26497:   val map_simpset: (simpset -> simpset) -> theory -> theory
wenzelm@24024:   val get_simproc: Context.generic -> xstring -> simproc
wenzelm@22236:   val def_simproc: {name: string, lhss: string list,
wenzelm@22236:     proc: morphism -> simpset -> cterm -> thm option, identifier: thm list} ->
wenzelm@22201:     local_theory -> local_theory
wenzelm@22236:   val def_simproc_i: {name: string, lhss: term list,
wenzelm@22236:     proc: morphism -> simpset -> cterm -> thm option, identifier: thm list} ->
wenzelm@22201:     local_theory -> local_theory
wenzelm@18033:   val cong_modifiers: (Args.T list -> (Method.modifier * Args.T list)) list
wenzelm@18033:   val simp_modifiers': (Args.T list -> (Method.modifier * Args.T list)) list
wenzelm@16014:   val simp_modifiers: (Args.T list -> (Method.modifier * Args.T list)) list
wenzelm@16014:   val method_setup: (Args.T list -> (Method.modifier * Args.T list)) list
wenzelm@18708:     -> theory -> theory
wenzelm@18708:   val easy_setup: thm -> thm list -> theory -> theory
wenzelm@16014: end;
wenzelm@16014: 
wenzelm@16014: structure Simplifier: SIMPLIFIER =
wenzelm@16014: struct
wenzelm@16014: 
wenzelm@21708: open MetaSimplifier;
wenzelm@21708: 
wenzelm@21708: 
wenzelm@17883: (** simpset data **)
wenzelm@16014: 
wenzelm@26497: structure SimpsetData = GenericDataFun
wenzelm@22846: (
wenzelm@26497:   type T = simpset;
wenzelm@26497:   val empty = empty_ss;
wenzelm@26497:   fun extend ss = MetaSimplifier.inherit_context empty_ss ss;
wenzelm@26497:   fun merge _ = merge_ss;
wenzelm@22846: );
wenzelm@16014: 
wenzelm@26497: val get_ss = SimpsetData.get;
wenzelm@26497: val map_ss = SimpsetData.map;
wenzelm@26497: 
wenzelm@26497: 
wenzelm@26497: (* attributes *)
wenzelm@26497: 
wenzelm@26497: fun attrib f = Thm.declaration_attribute (fn th => map_ss (fn ss => f (ss, [th])));
wenzelm@16014: 
wenzelm@26497: val simp_add = attrib (op addsimps);
wenzelm@26497: val simp_del = attrib (op delsimps);
wenzelm@26497: val cong_add = attrib (op addcongs);
wenzelm@26497: val cong_del = attrib (op delcongs);
wenzelm@26497: 
wenzelm@16014: 
wenzelm@26497: (* global simpset *)
wenzelm@26497: 
wenzelm@26497: fun map_simpset f = Context.theory_map (map_ss f);
wenzelm@26497: fun change_simpset f = Context.>> (Context.map_theory (map_simpset f));
wenzelm@26497: fun simpset_of thy = MetaSimplifier.context (ProofContext.init thy) (get_ss (Context.Theory thy));
wenzelm@26425: val simpset = simpset_of o ML_Context.the_global_context;
wenzelm@16014: 
wenzelm@17883: fun SIMPSET tacf st = tacf (simpset_of (Thm.theory_of_thm st)) st;
wenzelm@17883: fun SIMPSET' tacf i st = tacf (simpset_of (Thm.theory_of_thm st)) i st;
wenzelm@16014: 
wenzelm@17883: fun Addsimps args = change_simpset (fn ss => ss addsimps args);
wenzelm@17883: fun Delsimps args = change_simpset (fn ss => ss delsimps args);
wenzelm@17883: fun Addsimprocs args = change_simpset (fn ss => ss addsimprocs args);
wenzelm@17883: fun Delsimprocs args = change_simpset (fn ss => ss delsimprocs args);
wenzelm@17883: fun Addcongs args = change_simpset (fn ss => ss addcongs args);
wenzelm@17883: fun Delcongs args = change_simpset (fn ss => ss delcongs args);
wenzelm@16014: 
wenzelm@16014: 
wenzelm@26497: (* local simpset *)
wenzelm@16014: 
wenzelm@26497: fun local_simpset_of ctxt = MetaSimplifier.context ctxt (get_ss (Context.Proof ctxt));
wenzelm@16014: 
wenzelm@27338: val _ = ML_Antiquote.value "simpset"
wenzelm@27338:   (Scan.succeed "Simplifier.local_simpset_of (ML_Context.the_local_context ())");
wenzelm@22132: 
wenzelm@16014: 
wenzelm@17967: 
wenzelm@22201: (** named simprocs **)
wenzelm@22201: 
wenzelm@23655: fun err_dup_simproc name = error ("Duplicate simproc: " ^ quote name);
wenzelm@22201: 
wenzelm@22236: 
wenzelm@22204: (* data *)
wenzelm@22204: 
wenzelm@22201: structure Simprocs = GenericDataFun
wenzelm@22201: (
wenzelm@22236:   type T = simproc NameSpace.table;
wenzelm@22201:   val empty = NameSpace.empty_table;
wenzelm@22201:   val extend = I;
wenzelm@22236:   fun merge _ simprocs = NameSpace.merge_tables eq_simproc simprocs
wenzelm@23655:     handle Symtab.DUP dup => err_dup_simproc dup;
wenzelm@22201: );
wenzelm@22201: 
wenzelm@22204: 
wenzelm@22204: (* get simprocs *)
wenzelm@22204: 
wenzelm@24024: fun get_simproc context xname =
wenzelm@22204:   let
wenzelm@24024:     val (space, tab) = Simprocs.get context;
wenzelm@22204:     val name = NameSpace.intern space xname;
wenzelm@22204:   in
wenzelm@22204:     (case Symtab.lookup tab name of
wenzelm@22236:       SOME proc => proc
wenzelm@22204:     | NONE => error ("Undefined simplification procedure: " ^ quote name))
wenzelm@22204:   end;
wenzelm@22204: 
wenzelm@27338: val _ = ML_Antiquote.value "simproc" (Scan.lift Args.name >> (fn name =>
wenzelm@27338:   "Simplifier.get_simproc (ML_Context.the_generic_context ()) " ^ ML_Syntax.print_string name));
wenzelm@22204: 
wenzelm@22204: 
wenzelm@22204: (* define simprocs *)
wenzelm@22201: 
wenzelm@22201: local
wenzelm@22201: 
wenzelm@22236: fun gen_simproc prep {name, lhss, proc, identifier} lthy =
wenzelm@22201:   let
haftmann@28991:     val b = Binding.name name;
wenzelm@22236:     val naming = LocalTheory.full_naming lthy;
wenzelm@22236:     val simproc = make_simproc
haftmann@28991:       {name = LocalTheory.full_name lthy b,
wenzelm@22236:        lhss =
wenzelm@22236:         let
wenzelm@22236:           val lhss' = prep lthy lhss;
wenzelm@22236:           val ctxt' = lthy
wenzelm@22236:             |> fold Variable.declare_term lhss'
wenzelm@22236:             |> fold Variable.auto_fixes lhss';
wenzelm@22236:         in Variable.export_terms ctxt' lthy lhss' end
wenzelm@22236:         |> map (Thm.cterm_of (ProofContext.theory_of lthy)),
wenzelm@22236:        proc = proc,
wenzelm@22236:        identifier = identifier}
wenzelm@22236:       |> morph_simproc (LocalTheory.target_morphism lthy);
wenzelm@22201:   in
wenzelm@24024:     lthy |> LocalTheory.declaration (fn phi =>
wenzelm@22201:       let
haftmann@28991:         val b' = Morphism.binding phi b;
wenzelm@22236:         val simproc' = morph_simproc phi simproc;
wenzelm@22201:       in
wenzelm@24024:         Simprocs.map (fn simprocs =>
haftmann@28965:           NameSpace.bind naming (b', simproc') simprocs |> snd
haftmann@28863:             handle Symtab.DUP dup => err_dup_simproc dup)
wenzelm@24024:         #> map_ss (fn ss => ss addsimprocs [simproc'])
wenzelm@22201:       end)
wenzelm@22201:   end;
wenzelm@22201: 
wenzelm@22201: in
wenzelm@22201: 
wenzelm@24509: val def_simproc = gen_simproc Syntax.read_terms;
wenzelm@24509: val def_simproc_i = gen_simproc Syntax.check_terms;
wenzelm@22201: 
wenzelm@22201: end;
wenzelm@22201: 
wenzelm@22201: 
wenzelm@22201: 
wenzelm@17967: (** simplification tactics and rules **)
wenzelm@17967: 
wenzelm@17967: fun solve_all_tac solvers ss =
wenzelm@17967:   let
wenzelm@17967:     val (_, {subgoal_tac, ...}) = MetaSimplifier.rep_ss ss;
wenzelm@17967:     val solve_tac = subgoal_tac (MetaSimplifier.set_solvers solvers ss) THEN_ALL_NEW (K no_tac);
wenzelm@17967:   in DEPTH_SOLVE (solve_tac 1) end;
wenzelm@17967: 
wenzelm@17967: (*NOTE: may instantiate unknowns that appear also in other subgoals*)
wenzelm@17967: fun generic_simp_tac safe mode ss =
wenzelm@17967:   let
wenzelm@17967:     val (_, {loop_tacs, solvers = (unsafe_solvers, solvers), ...}) = MetaSimplifier.rep_ss ss;
haftmann@21286:     val loop_tac = FIRST' (map (fn (_, tac) => tac ss) (rev loop_tacs));
wenzelm@17967:     val solve_tac = FIRST' (map (MetaSimplifier.solver ss)
haftmann@22717:       (rev (if safe then solvers else unsafe_solvers)));
wenzelm@17967: 
wenzelm@17967:     fun simp_loop_tac i =
wenzelm@23536:       asm_rewrite_goal_tac mode (solve_all_tac unsafe_solvers) ss i THEN
wenzelm@17967:       (solve_tac i ORELSE TRY ((loop_tac THEN_ALL_NEW simp_loop_tac) i));
wenzelm@17967:   in simp_loop_tac end;
wenzelm@17967: 
wenzelm@17967: local
wenzelm@17967: 
wenzelm@17967: fun simp rew mode ss thm =
wenzelm@17967:   let
wenzelm@17967:     val (_, {solvers = (unsafe_solvers, _), ...}) = MetaSimplifier.rep_ss ss;
haftmann@22717:     val tacf = solve_all_tac (rev unsafe_solvers);
wenzelm@17967:     fun prover s th = Option.map #1 (Seq.pull (tacf s th));
wenzelm@17967:   in rew mode prover ss thm end;
wenzelm@17967: 
wenzelm@17967: in
wenzelm@17967: 
wenzelm@17967: val simp_thm = simp MetaSimplifier.rewrite_thm;
wenzelm@17967: val simp_cterm = simp MetaSimplifier.rewrite_cterm;
wenzelm@17967: 
wenzelm@17967: end;
wenzelm@17967: 
wenzelm@17967: 
wenzelm@16806: (* tactics *)
wenzelm@16806: 
wenzelm@16014: val simp_tac = generic_simp_tac false (false, false, false);
wenzelm@16014: val asm_simp_tac = generic_simp_tac false (false, true, false);
wenzelm@16014: val full_simp_tac = generic_simp_tac false (true, false, false);
wenzelm@16014: val asm_lr_simp_tac = generic_simp_tac false (true, true, false);
wenzelm@16014: val asm_full_simp_tac = generic_simp_tac false (true, true, true);
wenzelm@16014: val safe_asm_full_simp_tac = generic_simp_tac true (true, true, true);
wenzelm@16014: 
wenzelm@16014: (*the abstraction over the proof state delays the dereferencing*)
wenzelm@16014: fun          Simp_tac i st =          simp_tac (simpset ()) i st;
wenzelm@16014: fun      Asm_simp_tac i st =      asm_simp_tac (simpset ()) i st;
wenzelm@16014: fun     Full_simp_tac i st =     full_simp_tac (simpset ()) i st;
wenzelm@16014: fun   Asm_lr_simp_tac i st =   asm_lr_simp_tac (simpset ()) i st;
wenzelm@16014: fun Asm_full_simp_tac i st = asm_full_simp_tac (simpset ()) i st;
wenzelm@16014: 
wenzelm@16806: 
wenzelm@16806: (* conversions *)
wenzelm@16806: 
wenzelm@17967: val          simplify = simp_thm (false, false, false);
wenzelm@17967: val      asm_simplify = simp_thm (false, true, false);
wenzelm@17967: val     full_simplify = simp_thm (true, false, false);
wenzelm@17967: val   asm_lr_simplify = simp_thm (true, true, false);
wenzelm@17967: val asm_full_simplify = simp_thm (true, true, true);
wenzelm@16014: 
wenzelm@17967: val          rewrite = simp_cterm (false, false, false);
wenzelm@17967: val      asm_rewrite = simp_cterm (false, true, false);
wenzelm@17967: val     full_rewrite = simp_cterm (true, false, false);
wenzelm@17967: val   asm_lr_rewrite = simp_cterm (true, true, false);
wenzelm@17967: val asm_full_rewrite = simp_cterm (true, true, true);
wenzelm@16014: 
wenzelm@16014: 
wenzelm@16014: 
wenzelm@16014: (** concrete syntax of attributes **)
wenzelm@16014: 
wenzelm@16014: (* add / del *)
wenzelm@16014: 
wenzelm@16014: val simpN = "simp";
wenzelm@16014: val congN = "cong";
wenzelm@16014: val addN = "add";
wenzelm@16014: val delN = "del";
wenzelm@16014: val onlyN = "only";
wenzelm@16014: val no_asmN = "no_asm";
wenzelm@16014: val no_asm_useN = "no_asm_use";
wenzelm@16014: val no_asm_simpN = "no_asm_simp";
wenzelm@16014: val asm_lrN = "asm_lr";
wenzelm@16014: 
wenzelm@16014: 
wenzelm@24024: (* simprocs *)
wenzelm@24024: 
wenzelm@24024: local
wenzelm@24024: 
wenzelm@24024: val add_del =
wenzelm@24024:   (Args.del -- Args.colon >> K (op delsimprocs) ||
wenzelm@24024:     Scan.option (Args.add -- Args.colon) >> K (op addsimprocs))
wenzelm@24024:   >> (fn f => fn simproc => fn phi => Thm.declaration_attribute
wenzelm@24024:       (K (map_ss (fn ss => f (ss, [morph_simproc phi simproc])))));
wenzelm@24024: 
wenzelm@24024: in
wenzelm@24024: 
wenzelm@24024: val simproc_att = Attrib.syntax
wenzelm@24024:   (Scan.peek (fn context =>
wenzelm@24024:     add_del :|-- (fn decl =>
wenzelm@24024:       Scan.repeat1 (Args.named_attribute (decl o get_simproc context))
wenzelm@24024:       >> (Library.apply o map Morphism.form))));
wenzelm@24024: 
wenzelm@24024: end;
wenzelm@24124: 
wenzelm@24024: 
wenzelm@16014: (* conversions *)
wenzelm@16014: 
wenzelm@16014: local
wenzelm@16014: 
wenzelm@16014: fun conv_mode x =
wenzelm@16014:   ((Args.parens (Args.$$$ no_asmN) >> K simplify ||
wenzelm@16014:     Args.parens (Args.$$$ no_asm_simpN) >> K asm_simplify ||
wenzelm@16014:     Args.parens (Args.$$$ no_asm_useN) >> K full_simplify ||
wenzelm@16014:     Scan.succeed asm_full_simplify) |> Scan.lift) x;
wenzelm@16014: 
wenzelm@16014: in
wenzelm@16014: 
wenzelm@18688: val simplified =
wenzelm@27021:   Attrib.syntax (conv_mode -- Attrib.thms >> (fn (f, ths) => Thm.rule_attribute (fn context =>
wenzelm@27021:     f ((if null ths then I else MetaSimplifier.clear_ss)
wenzelm@27021:         (local_simpset_of (Context.proof_of context)) addsimps ths))));
wenzelm@16014: 
wenzelm@16014: end;
wenzelm@16014: 
wenzelm@16014: 
wenzelm@16014: (* setup attributes *)
wenzelm@16014: 
wenzelm@26463: val _ = Context.>> (Context.map_theory
wenzelm@18708:  (Attrib.add_attributes
wenzelm@24024:    [(simpN, Attrib.add_del_args simp_add simp_del, "declaration of Simplifier rewrite rule"),
wenzelm@18728:     (congN, Attrib.add_del_args cong_add cong_del, "declaration of Simplifier congruence rule"),
wenzelm@24024:     ("simproc", simproc_att, "declaration of simplification procedures"),
wenzelm@26463:     ("simplified", simplified, "simplified rule")]));
wenzelm@16014: 
wenzelm@16014: 
wenzelm@16014: 
wenzelm@16014: (** proof methods **)
wenzelm@16014: 
wenzelm@16014: (* simplification *)
wenzelm@16014: 
wenzelm@16014: val simp_options =
wenzelm@16014:  (Args.parens (Args.$$$ no_asmN) >> K simp_tac ||
wenzelm@16014:   Args.parens (Args.$$$ no_asm_simpN) >> K asm_simp_tac ||
wenzelm@16014:   Args.parens (Args.$$$ no_asm_useN) >> K full_simp_tac ||
wenzelm@16014:   Args.parens (Args.$$$ asm_lrN) >> K asm_lr_simp_tac ||
wenzelm@16014:   Scan.succeed asm_full_simp_tac);
wenzelm@16014: 
wenzelm@16014: val cong_modifiers =
wenzelm@18728:  [Args.$$$ congN -- Args.colon >> K ((I, cong_add): Method.modifier),
wenzelm@18728:   Args.$$$ congN -- Args.add -- Args.colon >> K (I, cong_add),
wenzelm@18728:   Args.$$$ congN -- Args.del -- Args.colon >> K (I, cong_del)];
wenzelm@16014: 
wenzelm@16014: val simp_modifiers =
wenzelm@18728:  [Args.$$$ simpN -- Args.colon >> K (I, simp_add),
wenzelm@18728:   Args.$$$ simpN -- Args.add -- Args.colon >> K (I, simp_add),
wenzelm@18728:   Args.$$$ simpN -- Args.del -- Args.colon >> K (I, simp_del),
wenzelm@17883:   Args.$$$ simpN -- Args.$$$ onlyN -- Args.colon
wenzelm@26497:     >> K (Context.proof_map (map_ss MetaSimplifier.clear_ss), simp_add)]
wenzelm@16014:    @ cong_modifiers;
wenzelm@16014: 
wenzelm@16014: val simp_modifiers' =
wenzelm@18728:  [Args.add -- Args.colon >> K (I, simp_add),
wenzelm@18728:   Args.del -- Args.colon >> K (I, simp_del),
wenzelm@18688:   Args.$$$ onlyN -- Args.colon
wenzelm@26497:     >> K (Context.proof_map (map_ss MetaSimplifier.clear_ss), simp_add)]
wenzelm@16014:    @ cong_modifiers;
wenzelm@16014: 
wenzelm@16014: fun simp_args more_mods =
wenzelm@24124:   Method.sectioned_args (Args.bang_facts -- Scan.lift simp_options)
wenzelm@16684:     (more_mods @ simp_modifiers');
wenzelm@16014: 
wenzelm@24124: fun simp_method (prems, tac) ctxt = Method.METHOD (fn facts =>
wenzelm@16014:   ALLGOALS (Method.insert_tac (prems @ facts)) THEN
wenzelm@24124:     (CHANGED_PROP o ALLGOALS o tac) (local_simpset_of ctxt));
wenzelm@16014: 
wenzelm@24124: fun simp_method' (prems, tac) ctxt = Method.METHOD (fn facts =>
wenzelm@16014:   HEADGOAL (Method.insert_tac (prems @ facts) THEN'
wenzelm@24124:       ((CHANGED_PROP) oo tac) (local_simpset_of ctxt)));
wenzelm@16014: 
wenzelm@16014: 
wenzelm@16014: 
wenzelm@18708: (** setup **)
wenzelm@18708: 
wenzelm@18708: fun method_setup more_mods = Method.add_methods
wenzelm@16014:  [(simpN, simp_args more_mods simp_method', "simplification"),
wenzelm@16014:   ("simp_all", simp_args more_mods simp_method, "simplification (all goals)")];
wenzelm@16014: 
wenzelm@26497: fun easy_setup reflect trivs = method_setup [] #> Context.theory_map (map_ss (fn _ =>
wenzelm@16014:   let
wenzelm@16014:     val trivialities = Drule.reflexive_thm :: trivs;
wenzelm@16014: 
wenzelm@16014:     fun unsafe_solver_tac prems = FIRST' [resolve_tac (trivialities @ prems), assume_tac];
wenzelm@16014:     val unsafe_solver = mk_solver "easy unsafe" unsafe_solver_tac;
wenzelm@16014: 
wenzelm@16014:     (*no premature instantiation of variables during simplification*)
wenzelm@16014:     fun safe_solver_tac prems = FIRST' [match_tac (trivialities @ prems), eq_assume_tac];
wenzelm@16014:     val safe_solver = mk_solver "easy safe" safe_solver_tac;
wenzelm@16014: 
wenzelm@16014:     fun mk_eq thm =
wenzelm@20872:       if can Logic.dest_equals (Thm.concl_of thm) then [thm]
wenzelm@16014:       else [thm RS reflect] handle THM _ => [];
wenzelm@16014: 
wenzelm@26653:     fun mksimps thm = mk_eq (Thm.forall_elim_vars (#maxidx (Thm.rep_thm thm) + 1) thm);
wenzelm@26497:   in
wenzelm@26497:     empty_ss setsubgoaler asm_simp_tac
wenzelm@26497:     setSSolver safe_solver
wenzelm@26497:     setSolver unsafe_solver
wenzelm@26497:     setmksimps mksimps
wenzelm@26497:   end));
wenzelm@16014: 
wenzelm@16014: end;
wenzelm@16014: 
wenzelm@16014: structure BasicSimplifier: BASIC_SIMPLIFIER = Simplifier;
wenzelm@16014: open BasicSimplifier;