src/Pure/simplifier.ML
author wenzelm
Mon Jan 29 19:58:14 2007 +0100 (2007-01-29)
changeset 22204 33da3a55c00e
parent 22201 6fe46a7259ec
child 22236 1502e0138d5b
permissions -rw-r--r--
added get_simproc, @{simproc};
     1 (*  Title:      Pure/simplifier.ML
     2     ID:         $Id$
     3     Author:     Tobias Nipkow and Markus Wenzel, TU Muenchen
     4 
     5 Generic simplifier, suitable for most logics (see also
     6 meta_simplifier.ML for the actual meta-level rewriting engine).
     7 *)
     8 
     9 signature BASIC_SIMPLIFIER =
    10 sig
    11   include BASIC_META_SIMPLIFIER
    12   val print_simpset: theory -> unit
    13   val change_simpset_of: theory -> (simpset -> simpset) -> unit
    14   val change_simpset: (simpset -> simpset) -> unit
    15   val simpset_of: theory -> simpset
    16   val simpset: unit -> simpset
    17   val SIMPSET: (simpset -> tactic) -> tactic
    18   val SIMPSET': (simpset -> 'a -> tactic) -> 'a -> tactic
    19   val Addsimps: thm list -> unit
    20   val Delsimps: thm list -> unit
    21   val Addsimprocs: simproc list -> unit
    22   val Delsimprocs: simproc list -> unit
    23   val Addcongs: thm list -> unit
    24   val Delcongs: thm list -> unit
    25   val local_simpset_of: Proof.context -> simpset
    26   val generic_simp_tac: bool -> bool * bool * bool -> simpset -> int -> tactic
    27   val safe_asm_full_simp_tac: simpset -> int -> tactic
    28   val               simp_tac: simpset -> int -> tactic
    29   val           asm_simp_tac: simpset -> int -> tactic
    30   val          full_simp_tac: simpset -> int -> tactic
    31   val        asm_lr_simp_tac: simpset -> int -> tactic
    32   val      asm_full_simp_tac: simpset -> int -> tactic
    33   val               Simp_tac:            int -> tactic
    34   val           Asm_simp_tac:            int -> tactic
    35   val          Full_simp_tac:            int -> tactic
    36   val        Asm_lr_simp_tac:            int -> tactic
    37   val      Asm_full_simp_tac:            int -> tactic
    38   val          simplify: simpset -> thm -> thm
    39   val      asm_simplify: simpset -> thm -> thm
    40   val     full_simplify: simpset -> thm -> thm
    41   val   asm_lr_simplify: simpset -> thm -> thm
    42   val asm_full_simplify: simpset -> thm -> thm
    43 end;
    44 
    45 signature SIMPLIFIER =
    46 sig
    47   include BASIC_SIMPLIFIER
    48   val clear_ss: simpset -> simpset
    49   val debug_bounds: bool ref
    50   val inherit_context: simpset -> simpset -> simpset
    51   val the_context: simpset -> Proof.context
    52   val context: Proof.context -> simpset -> simpset
    53   val theory_context: theory  -> simpset -> simpset
    54   val simproc_i: theory -> string -> term list
    55     -> (theory -> simpset -> term -> thm option) -> simproc
    56   val simproc: theory -> string -> string list
    57     -> (theory -> simpset -> term -> thm option) -> simproc
    58   val          rewrite: simpset -> cterm -> thm
    59   val      asm_rewrite: simpset -> cterm -> thm
    60   val     full_rewrite: simpset -> cterm -> thm
    61   val   asm_lr_rewrite: simpset -> cterm -> thm
    62   val asm_full_rewrite: simpset -> cterm -> thm
    63   val get_simpset: theory -> simpset
    64   val print_local_simpset: Proof.context -> unit
    65   val get_local_simpset: Proof.context -> simpset
    66   val put_local_simpset: simpset -> Proof.context -> Proof.context
    67   val attrib: (simpset * thm list -> simpset) -> attribute
    68   val simp_add: attribute
    69   val simp_del: attribute
    70   val cong_add: attribute
    71   val cong_del: attribute
    72   val get_simproc: Proof.context -> xstring -> simproc
    73   val def_simproc: string -> string list -> (morphism -> simpset -> cterm -> thm option) ->
    74     local_theory -> local_theory
    75   val def_simproc_i: string -> term list -> (morphism -> simpset -> cterm -> thm option) ->
    76     local_theory -> local_theory
    77   val cong_modifiers: (Args.T list -> (Method.modifier * Args.T list)) list
    78   val simp_modifiers': (Args.T list -> (Method.modifier * Args.T list)) list
    79   val simp_modifiers: (Args.T list -> (Method.modifier * Args.T list)) list
    80   val method_setup: (Args.T list -> (Method.modifier * Args.T list)) list
    81     -> theory -> theory
    82   val easy_setup: thm -> thm list -> theory -> theory
    83 end;
    84 
    85 structure Simplifier: SIMPLIFIER =
    86 struct
    87 
    88 open MetaSimplifier;
    89 
    90 
    91 (** simpset data **)
    92 
    93 (* global simpsets *)
    94 
    95 structure GlobalSimpset = TheoryDataFun
    96 (struct
    97   val name = "Pure/simpset";
    98   type T = simpset ref;
    99 
   100   val empty = ref empty_ss;
   101   fun copy (ref ss) = ref ss: T;            (*create new reference!*)
   102   fun extend (ref ss) = ref (MetaSimplifier.inherit_context empty_ss ss);
   103   fun merge _ (ref ss1, ref ss2) = ref (merge_ss (ss1, ss2));
   104   fun print _ (ref ss) = print_ss ss;
   105 end);
   106 
   107 val _ = Context.add_setup GlobalSimpset.init;
   108 val print_simpset = GlobalSimpset.print;
   109 val get_simpset = ! o GlobalSimpset.get;
   110 
   111 val change_simpset_of = change o GlobalSimpset.get;
   112 fun change_simpset f = change_simpset_of (ML_Context.the_context ()) f;
   113 
   114 fun simpset_of thy = MetaSimplifier.context (ProofContext.init thy) (get_simpset thy);
   115 val simpset = simpset_of o ML_Context.the_context;
   116 
   117 
   118 fun SIMPSET tacf st = tacf (simpset_of (Thm.theory_of_thm st)) st;
   119 fun SIMPSET' tacf i st = tacf (simpset_of (Thm.theory_of_thm st)) i st;
   120 
   121 fun Addsimps args = change_simpset (fn ss => ss addsimps args);
   122 fun Delsimps args = change_simpset (fn ss => ss delsimps args);
   123 fun Addsimprocs args = change_simpset (fn ss => ss addsimprocs args);
   124 fun Delsimprocs args = change_simpset (fn ss => ss delsimprocs args);
   125 fun Addcongs args = change_simpset (fn ss => ss addcongs args);
   126 fun Delcongs args = change_simpset (fn ss => ss delcongs args);
   127 
   128 
   129 (* local simpsets *)
   130 
   131 structure LocalSimpset = ProofDataFun
   132 (struct
   133   val name = "Pure/simpset";
   134   type T = simpset;
   135   val init = get_simpset;
   136   fun print _ ss = print_ss ss;
   137 end);
   138 
   139 val _ = Context.add_setup LocalSimpset.init;
   140 val print_local_simpset = LocalSimpset.print;
   141 val get_local_simpset = LocalSimpset.get;
   142 val put_local_simpset = LocalSimpset.put;
   143 
   144 fun local_simpset_of ctxt = MetaSimplifier.context ctxt (get_local_simpset ctxt);
   145 
   146 val _ = ML_Context.value_antiq "simpset"
   147   (Scan.succeed ("simpset", "Simplifier.local_simpset_of (ML_Context.the_local_context ())"));
   148 
   149 
   150 (* generic simpsets *)
   151 
   152 fun get_ss (Context.Theory thy) = simpset_of thy
   153   | get_ss (Context.Proof ctxt) = local_simpset_of ctxt;
   154 
   155 fun map_ss f (Context.Theory thy) = (change_simpset_of thy f; Context.Theory thy)
   156   | map_ss f (Context.Proof ctxt) = Context.Proof (LocalSimpset.map f ctxt);
   157 
   158 
   159 (* attributes *)
   160 
   161 fun attrib f = Thm.declaration_attribute (fn th => map_ss (fn ss => f (ss, [th])));
   162 
   163 val simp_add = attrib (op addsimps);
   164 val simp_del = attrib (op delsimps);
   165 val cong_add = attrib (op addcongs);
   166 val cong_del = attrib (op delcongs);
   167 
   168 
   169 
   170 (** named simprocs **)
   171 
   172 fun err_dup_simprocs ds =
   173   error ("Duplicate simproc(s): " ^ commas_quote ds);
   174 
   175 (* data *)
   176 
   177 structure Simprocs = GenericDataFun
   178 (
   179   val name = "Pure/simprocs";
   180   type T = (simproc * stamp) NameSpace.table;
   181   val empty = NameSpace.empty_table;
   182   val extend = I;
   183   fun merge _ simprocs = NameSpace.merge_tables (eq_snd (op =)) simprocs
   184     handle Symtab.DUPS ds => err_dup_simprocs ds;
   185   fun print _ _ = ();
   186 );
   187 val _ = Context.add_setup Simprocs.init;
   188 
   189 
   190 (* get simprocs *)
   191 
   192 fun get_simproc ctxt xname =
   193   let
   194     val (space, tab) = Simprocs.get (Context.Proof ctxt);
   195     val name = NameSpace.intern space xname;
   196   in
   197     (case Symtab.lookup tab name of
   198       SOME (proc, _) => proc
   199     | NONE => error ("Undefined simplification procedure: " ^ quote name))
   200   end;
   201 
   202 val _ = ML_Context.value_antiq "simproc" (Scan.lift Args.name >> (fn name =>
   203   ("simproc",
   204     "Simplifier.get_simproc (ML_Context.the_local_context ()) " ^ ML_Syntax.print_string name)));
   205 
   206 
   207 (* define simprocs *)
   208 
   209 local
   210 
   211 (* FIXME *)
   212 fun read_terms ctxt ts =
   213   #1 (ProofContext.read_termTs ctxt (K false) (K NONE) (K NONE) []
   214     (map (rpair TypeInfer.logicT) ts));
   215 
   216 (* FIXME *)
   217 fun cert_terms ctxt ts = map (ProofContext.cert_term ctxt) ts;
   218 
   219 fun prep_pats prep ctxt raw_pats =
   220   let
   221     val pats = prep ctxt raw_pats;
   222     val ctxt' = ctxt
   223       |> fold Variable.declare_term pats
   224       |> fold Variable.auto_fixes pats;
   225   in Variable.export_terms ctxt' ctxt pats end;
   226 
   227 fun gen_simproc prep name raw_pats proc lthy =
   228   let
   229     val pats =
   230       prep_pats prep lthy raw_pats
   231       |> map (Morphism.term (LocalTheory.target_morphism lthy));
   232     val naming = LocalTheory.target_naming lthy;
   233   in
   234     lthy |> LocalTheory.declaration (fn phi => fn context =>
   235       let
   236         val cert = Thm.cterm_of (Context.theory_of context);
   237         val pats' = map (cert o Morphism.term phi) pats;
   238         val name' = Morphism.name phi name;
   239         val proc' = proc phi;
   240         val simproc = mk_simproc' (NameSpace.full naming name') pats' proc';
   241       in
   242         context
   243         |> Simprocs.map (fn simprocs =>
   244             NameSpace.extend_table naming (simprocs, [(name', (simproc, stamp ()))])
   245               handle Symtab.DUPS ds => err_dup_simprocs ds)
   246         |> map_ss (fn ss => ss addsimprocs [simproc])
   247       end)
   248   end;
   249 
   250 in
   251 
   252 val def_simproc = gen_simproc read_terms;
   253 val def_simproc_i = gen_simproc cert_terms;
   254 
   255 end;
   256 
   257 
   258 
   259 (** simplification tactics and rules **)
   260 
   261 fun solve_all_tac solvers ss =
   262   let
   263     val (_, {subgoal_tac, ...}) = MetaSimplifier.rep_ss ss;
   264     val solve_tac = subgoal_tac (MetaSimplifier.set_solvers solvers ss) THEN_ALL_NEW (K no_tac);
   265   in DEPTH_SOLVE (solve_tac 1) end;
   266 
   267 (*NOTE: may instantiate unknowns that appear also in other subgoals*)
   268 fun generic_simp_tac safe mode ss =
   269   let
   270     val (_, {loop_tacs, solvers = (unsafe_solvers, solvers), ...}) = MetaSimplifier.rep_ss ss;
   271     val loop_tac = FIRST' (map (fn (_, tac) => tac ss) (rev loop_tacs));
   272     val solve_tac = FIRST' (map (MetaSimplifier.solver ss)
   273       (if safe then solvers else unsafe_solvers));
   274 
   275     fun simp_loop_tac i =
   276       Goal.asm_rewrite_goal_tac mode (solve_all_tac unsafe_solvers) ss i THEN
   277       (solve_tac i ORELSE TRY ((loop_tac THEN_ALL_NEW simp_loop_tac) i));
   278   in simp_loop_tac end;
   279 
   280 local
   281 
   282 fun simp rew mode ss thm =
   283   let
   284     val (_, {solvers = (unsafe_solvers, _), ...}) = MetaSimplifier.rep_ss ss;
   285     val tacf = solve_all_tac unsafe_solvers;
   286     fun prover s th = Option.map #1 (Seq.pull (tacf s th));
   287   in rew mode prover ss thm end;
   288 
   289 in
   290 
   291 val simp_thm = simp MetaSimplifier.rewrite_thm;
   292 val simp_cterm = simp MetaSimplifier.rewrite_cterm;
   293 
   294 end;
   295 
   296 
   297 (* tactics *)
   298 
   299 val simp_tac = generic_simp_tac false (false, false, false);
   300 val asm_simp_tac = generic_simp_tac false (false, true, false);
   301 val full_simp_tac = generic_simp_tac false (true, false, false);
   302 val asm_lr_simp_tac = generic_simp_tac false (true, true, false);
   303 val asm_full_simp_tac = generic_simp_tac false (true, true, true);
   304 val safe_asm_full_simp_tac = generic_simp_tac true (true, true, true);
   305 
   306 (*the abstraction over the proof state delays the dereferencing*)
   307 fun          Simp_tac i st =          simp_tac (simpset ()) i st;
   308 fun      Asm_simp_tac i st =      asm_simp_tac (simpset ()) i st;
   309 fun     Full_simp_tac i st =     full_simp_tac (simpset ()) i st;
   310 fun   Asm_lr_simp_tac i st =   asm_lr_simp_tac (simpset ()) i st;
   311 fun Asm_full_simp_tac i st = asm_full_simp_tac (simpset ()) i st;
   312 
   313 
   314 (* conversions *)
   315 
   316 val          simplify = simp_thm (false, false, false);
   317 val      asm_simplify = simp_thm (false, true, false);
   318 val     full_simplify = simp_thm (true, false, false);
   319 val   asm_lr_simplify = simp_thm (true, true, false);
   320 val asm_full_simplify = simp_thm (true, true, true);
   321 
   322 val          rewrite = simp_cterm (false, false, false);
   323 val      asm_rewrite = simp_cterm (false, true, false);
   324 val     full_rewrite = simp_cterm (true, false, false);
   325 val   asm_lr_rewrite = simp_cterm (true, true, false);
   326 val asm_full_rewrite = simp_cterm (true, true, true);
   327 
   328 
   329 
   330 (** concrete syntax of attributes **)
   331 
   332 (* add / del *)
   333 
   334 val simpN = "simp";
   335 val congN = "cong";
   336 val addN = "add";
   337 val delN = "del";
   338 val onlyN = "only";
   339 val no_asmN = "no_asm";
   340 val no_asm_useN = "no_asm_use";
   341 val no_asm_simpN = "no_asm_simp";
   342 val asm_lrN = "asm_lr";
   343 
   344 
   345 (* conversions *)
   346 
   347 local
   348 
   349 fun conv_mode x =
   350   ((Args.parens (Args.$$$ no_asmN) >> K simplify ||
   351     Args.parens (Args.$$$ no_asm_simpN) >> K asm_simplify ||
   352     Args.parens (Args.$$$ no_asm_useN) >> K full_simplify ||
   353     Scan.succeed asm_full_simplify) |> Scan.lift) x;
   354 
   355 in
   356 
   357 val simplified =
   358   Attrib.syntax (conv_mode -- Attrib.thms >> (fn (f, ths) => Thm.rule_attribute (fn x =>
   359     f ((if null ths then I else MetaSimplifier.clear_ss) (get_ss x) addsimps ths))));
   360 
   361 end;
   362 
   363 
   364 (* setup attributes *)
   365 
   366 val _ = Context.add_setup
   367  (Attrib.add_attributes
   368    [(simpN, Attrib.add_del_args simp_add simp_del, "declaration of Simplifier rule"),
   369     (congN, Attrib.add_del_args cong_add cong_del, "declaration of Simplifier congruence rule"),
   370     ("simplified", simplified, "simplified rule")]);
   371 
   372 
   373 
   374 (** proof methods **)
   375 
   376 (* simplification *)
   377 
   378 val simp_options =
   379  (Args.parens (Args.$$$ no_asmN) >> K simp_tac ||
   380   Args.parens (Args.$$$ no_asm_simpN) >> K asm_simp_tac ||
   381   Args.parens (Args.$$$ no_asm_useN) >> K full_simp_tac ||
   382   Args.parens (Args.$$$ asm_lrN) >> K asm_lr_simp_tac ||
   383   Scan.succeed asm_full_simp_tac);
   384 
   385 fun simp_flags x = (Scan.repeat
   386   (Args.parens (Args.$$$ "depth_limit" -- Args.colon |-- Args.nat)
   387     >> setmp MetaSimplifier.simp_depth_limit)
   388   >> (curry (Library.foldl op o) I o rev)) x;
   389 
   390 val cong_modifiers =
   391  [Args.$$$ congN -- Args.colon >> K ((I, cong_add): Method.modifier),
   392   Args.$$$ congN -- Args.add -- Args.colon >> K (I, cong_add),
   393   Args.$$$ congN -- Args.del -- Args.colon >> K (I, cong_del)];
   394 
   395 val simp_modifiers =
   396  [Args.$$$ simpN -- Args.colon >> K (I, simp_add),
   397   Args.$$$ simpN -- Args.add -- Args.colon >> K (I, simp_add),
   398   Args.$$$ simpN -- Args.del -- Args.colon >> K (I, simp_del),
   399   Args.$$$ simpN -- Args.$$$ onlyN -- Args.colon
   400     >> K (LocalSimpset.map MetaSimplifier.clear_ss, simp_add)]
   401    @ cong_modifiers;
   402 
   403 val simp_modifiers' =
   404  [Args.add -- Args.colon >> K (I, simp_add),
   405   Args.del -- Args.colon >> K (I, simp_del),
   406   Args.$$$ onlyN -- Args.colon
   407     >> K (LocalSimpset.map MetaSimplifier.clear_ss, simp_add)]
   408    @ cong_modifiers;
   409 
   410 fun simp_args more_mods =
   411   Method.sectioned_args (Args.bang_facts -- Scan.lift simp_options -- Scan.lift simp_flags)
   412     (more_mods @ simp_modifiers');
   413 
   414 fun simp_method ((prems, tac), FLAGS) ctxt = Method.METHOD (fn facts =>
   415   ALLGOALS (Method.insert_tac (prems @ facts)) THEN
   416     (FLAGS o CHANGED_PROP o ALLGOALS o tac) (local_simpset_of ctxt));
   417 
   418 fun simp_method' ((prems, tac), FLAGS) ctxt = Method.METHOD (fn facts =>
   419   HEADGOAL (Method.insert_tac (prems @ facts) THEN'
   420       ((FLAGS o CHANGED_PROP) oo tac) (local_simpset_of ctxt)));
   421 
   422 
   423 
   424 (** setup **)
   425 
   426 fun method_setup more_mods = Method.add_methods
   427  [(simpN, simp_args more_mods simp_method', "simplification"),
   428   ("simp_all", simp_args more_mods simp_method, "simplification (all goals)")];
   429 
   430 fun easy_setup reflect trivs = method_setup [] #> (fn thy =>
   431   let
   432     val trivialities = Drule.reflexive_thm :: trivs;
   433 
   434     fun unsafe_solver_tac prems = FIRST' [resolve_tac (trivialities @ prems), assume_tac];
   435     val unsafe_solver = mk_solver "easy unsafe" unsafe_solver_tac;
   436 
   437     (*no premature instantiation of variables during simplification*)
   438     fun safe_solver_tac prems = FIRST' [match_tac (trivialities @ prems), eq_assume_tac];
   439     val safe_solver = mk_solver "easy safe" safe_solver_tac;
   440 
   441     fun mk_eq thm =
   442       if can Logic.dest_equals (Thm.concl_of thm) then [thm]
   443       else [thm RS reflect] handle THM _ => [];
   444 
   445     fun mksimps thm = mk_eq (Drule.forall_elim_vars (#maxidx (Thm.rep_thm thm) + 1) thm);
   446   in
   447     GlobalSimpset.get thy :=
   448       empty_ss setsubgoaler asm_simp_tac
   449       setSSolver safe_solver
   450       setSolver unsafe_solver
   451       setmksimps mksimps;
   452     thy
   453   end);
   454 
   455 end;
   456 
   457 structure BasicSimplifier: BASIC_SIMPLIFIER = Simplifier;
   458 open BasicSimplifier;