isabelle: src/Pure/simplifier.ML@e03a43b8178c

     1 (*  Title:      Pure/simplifier.ML

     2     ID:         $Id$

     3     Author:     Tobias Nipkow and Markus Wenzel, TU Muenchen

     5 Generic simplifier, suitable for most logics (see also

     6 meta_simplifier.ML for the actual meta-level rewriting engine).

     7 *)

     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;

    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 -> conv

    59   val      asm_rewrite: simpset -> conv

    60   val     full_rewrite: simpset -> conv

    61   val   asm_lr_rewrite: simpset -> conv

    62   val asm_full_rewrite: simpset -> conv

    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 get_ss: Context.generic -> simpset

    68   val map_ss: (simpset -> simpset) -> Context.generic -> Context.generic

    69   val attrib: (simpset * thm list -> simpset) -> attribute

    70   val simp_add: attribute

    71   val simp_del: attribute

    72   val cong_add: attribute

    73   val cong_del: attribute

    74   val get_simproc: Proof.context -> xstring -> simproc

    75   val def_simproc: {name: string, lhss: string list,

    76     proc: morphism -> simpset -> cterm -> thm option, identifier: thm list} ->

    77     local_theory -> local_theory

    78   val def_simproc_i: {name: string, lhss: term list,

    79     proc: morphism -> simpset -> cterm -> thm option, identifier: thm list} ->

    80     local_theory -> local_theory

    81   val cong_modifiers: (Args.T list -> (Method.modifier * Args.T list)) list

    82   val simp_modifiers': (Args.T list -> (Method.modifier * Args.T list)) list

    83   val simp_modifiers: (Args.T list -> (Method.modifier * Args.T list)) list

    84   val method_setup: (Args.T list -> (Method.modifier * Args.T list)) list

    85     -> theory -> theory

    86   val easy_setup: thm -> thm list -> theory -> theory

    87 end;

    89 structure Simplifier: SIMPLIFIER =

    90 struct

    92 open MetaSimplifier;

    95 (** simpset data **)

    97 (* global simpsets *)

    99 structure GlobalSimpset = TheoryDataFun

   100 (

   101   type T = simpset ref;

   102   val empty = ref empty_ss;

   103   fun copy (ref ss) = ref ss: T;

   104   fun extend (ref ss) = ref (MetaSimplifier.inherit_context empty_ss ss);

   105   fun merge _ (ref ss1, ref ss2) = ref (merge_ss (ss1, ss2));

   106 );

   108 val _ = Context.add_setup GlobalSimpset.init;

   109 fun print_simpset thy = print_ss (! (GlobalSimpset.get thy));

   110 val get_simpset = ! o GlobalSimpset.get;

   112 val change_simpset_of = change o GlobalSimpset.get;

   113 fun change_simpset f = change_simpset_of (ML_Context.the_context ()) f;

   115 fun simpset_of thy = MetaSimplifier.context (ProofContext.init thy) (get_simpset thy);

   116 val simpset = simpset_of o ML_Context.the_context;

   119 fun SIMPSET tacf st = tacf (simpset_of (Thm.theory_of_thm st)) st;

   120 fun SIMPSET' tacf i st = tacf (simpset_of (Thm.theory_of_thm st)) i st;

   122 fun Addsimps args = change_simpset (fn ss => ss addsimps args);

   123 fun Delsimps args = change_simpset (fn ss => ss delsimps args);

   124 fun Addsimprocs args = change_simpset (fn ss => ss addsimprocs args);

   125 fun Delsimprocs args = change_simpset (fn ss => ss delsimprocs args);

   126 fun Addcongs args = change_simpset (fn ss => ss addcongs args);

   127 fun Delcongs args = change_simpset (fn ss => ss delcongs args);

   130 (* local simpsets *)

   132 structure LocalSimpset = ProofDataFun

   133 (

   134   type T = simpset;

   135   val init = get_simpset;

   136 );

   138 val print_local_simpset = print_ss o LocalSimpset.get;

   139 val get_local_simpset = LocalSimpset.get;

   140 val put_local_simpset = LocalSimpset.put;

   142 fun local_simpset_of ctxt = MetaSimplifier.context ctxt (get_local_simpset ctxt);

   144 val _ = ML_Context.value_antiq "simpset"

   145   (Scan.succeed ("simpset", "Simplifier.local_simpset_of (ML_Context.the_local_context ())"));

   148 (* generic simpsets *)

   150 fun get_ss (Context.Theory thy) = simpset_of thy

   151   | get_ss (Context.Proof ctxt) = local_simpset_of ctxt;

   153 fun map_ss f (Context.Theory thy) = (change_simpset_of thy f; Context.Theory thy)

   154   | map_ss f (Context.Proof ctxt) = Context.Proof (LocalSimpset.map f ctxt);

   157 (* attributes *)

   159 fun attrib f = Thm.declaration_attribute (fn th => map_ss (fn ss => f (ss, [th])));

   161 val simp_add = attrib (op addsimps);

   162 val simp_del = attrib (op delsimps);

   163 val cong_add = attrib (op addcongs);

   164 val cong_del = attrib (op delcongs);

   168 (** named simprocs **)

   170 fun err_dup_simprocs ds =

   171   error ("Duplicate simproc(s): " ^ commas_quote ds);

   174 (* data *)

   176 structure Simprocs = GenericDataFun

   177 (

   178   type T = simproc NameSpace.table;

   179   val empty = NameSpace.empty_table;

   180   val extend = I;

   181   fun merge _ simprocs = NameSpace.merge_tables eq_simproc simprocs

   182     handle Symtab.DUPS ds => err_dup_simprocs ds;

   183 );

   186 (* get simprocs *)

   188 fun get_simproc ctxt xname =

   189   let

   190     val (space, tab) = Simprocs.get (Context.Proof ctxt);

   191     val name = NameSpace.intern space xname;

   192   in

   193     (case Symtab.lookup tab name of

   194       SOME proc => proc

   195     | NONE => error ("Undefined simplification procedure: " ^ quote name))

   196   end;

   198 val _ = ML_Context.value_antiq "simproc" (Scan.lift Args.name >> (fn name =>

   199   ("simproc",

   200     "Simplifier.get_simproc (ML_Context.the_local_context ()) " ^ ML_Syntax.print_string name)));

   203 (* define simprocs *)

   205 local

   207 fun gen_simproc prep {name, lhss, proc, identifier} lthy =

   208   let

   209     val naming = LocalTheory.full_naming lthy;

   210     val simproc = make_simproc

   211       {name = LocalTheory.full_name lthy name,

   212        lhss =

   213         let

   214           val lhss' = prep lthy lhss;

   215           val ctxt' = lthy

   216             |> fold Variable.declare_term lhss'

   217             |> fold Variable.auto_fixes lhss';

   218         in Variable.export_terms ctxt' lthy lhss' end

   219         |> map (Thm.cterm_of (ProofContext.theory_of lthy)),

   220        proc = proc,

   221        identifier = identifier}

   222       |> morph_simproc (LocalTheory.target_morphism lthy);

   223   in

   224     lthy |> LocalTheory.declaration (fn phi => fn context =>

   225       let

   226         val name' = Morphism.name phi name;

   227         val simproc' = morph_simproc phi simproc;

   228       in

   229         context

   230         |> Simprocs.map (fn simprocs =>

   231             NameSpace.extend_table naming [(name', simproc')] simprocs

   232               handle Symtab.DUPS ds => err_dup_simprocs ds)

   233         |> map_ss (fn ss => ss addsimprocs [simproc'])

   234       end)

   235   end;

   237 in

   239 val def_simproc = gen_simproc ProofContext.read_terms;

   240 val def_simproc_i = gen_simproc ProofContext.cert_terms;

   242 end;

   246 (** simplification tactics and rules **)

   248 fun solve_all_tac solvers ss =

   249   let

   250     val (_, {subgoal_tac, ...}) = MetaSimplifier.rep_ss ss;

   251     val solve_tac = subgoal_tac (MetaSimplifier.set_solvers solvers ss) THEN_ALL_NEW (K no_tac);

   252   in DEPTH_SOLVE (solve_tac 1) end;

   254 (*NOTE: may instantiate unknowns that appear also in other subgoals*)

   255 fun generic_simp_tac safe mode ss =

   256   let

   257     val (_, {loop_tacs, solvers = (unsafe_solvers, solvers), ...}) = MetaSimplifier.rep_ss ss;

   258     val loop_tac = FIRST' (map (fn (_, tac) => tac ss) (rev loop_tacs));

   259     val solve_tac = FIRST' (map (MetaSimplifier.solver ss)

   260       (rev (if safe then solvers else unsafe_solvers)));

   262     fun simp_loop_tac i =

   263       asm_rewrite_goal_tac mode (solve_all_tac unsafe_solvers) ss i THEN

   264       (solve_tac i ORELSE TRY ((loop_tac THEN_ALL_NEW simp_loop_tac) i));

   265   in simp_loop_tac end;

   267 local

   269 fun simp rew mode ss thm =

   270   let

   271     val (_, {solvers = (unsafe_solvers, _), ...}) = MetaSimplifier.rep_ss ss;

   272     val tacf = solve_all_tac (rev unsafe_solvers);

   273     fun prover s th = Option.map #1 (Seq.pull (tacf s th));

   274   in rew mode prover ss thm end;

   276 in

   278 val simp_thm = simp MetaSimplifier.rewrite_thm;

   279 val simp_cterm = simp MetaSimplifier.rewrite_cterm;

   281 end;

   284 (* tactics *)

   286 val simp_tac = generic_simp_tac false (false, false, false);

   287 val asm_simp_tac = generic_simp_tac false (false, true, false);

   288 val full_simp_tac = generic_simp_tac false (true, false, false);

   289 val asm_lr_simp_tac = generic_simp_tac false (true, true, false);

   290 val asm_full_simp_tac = generic_simp_tac false (true, true, true);

   291 val safe_asm_full_simp_tac = generic_simp_tac true (true, true, true);

   293 (*the abstraction over the proof state delays the dereferencing*)

   294 fun          Simp_tac i st =          simp_tac (simpset ()) i st;

   295 fun      Asm_simp_tac i st =      asm_simp_tac (simpset ()) i st;

   296 fun     Full_simp_tac i st =     full_simp_tac (simpset ()) i st;

   297 fun   Asm_lr_simp_tac i st =   asm_lr_simp_tac (simpset ()) i st;

   298 fun Asm_full_simp_tac i st = asm_full_simp_tac (simpset ()) i st;

   301 (* conversions *)

   303 val          simplify = simp_thm (false, false, false);

   304 val      asm_simplify = simp_thm (false, true, false);

   305 val     full_simplify = simp_thm (true, false, false);

   306 val   asm_lr_simplify = simp_thm (true, true, false);

   307 val asm_full_simplify = simp_thm (true, true, true);

   309 val          rewrite = simp_cterm (false, false, false);

   310 val      asm_rewrite = simp_cterm (false, true, false);

   311 val     full_rewrite = simp_cterm (true, false, false);

   312 val   asm_lr_rewrite = simp_cterm (true, true, false);

   313 val asm_full_rewrite = simp_cterm (true, true, true);

   317 (** concrete syntax of attributes **)

   319 (* add / del *)

   321 val simpN = "simp";

   322 val congN = "cong";

   323 val addN = "add";

   324 val delN = "del";

   325 val onlyN = "only";

   326 val no_asmN = "no_asm";

   327 val no_asm_useN = "no_asm_use";

   328 val no_asm_simpN = "no_asm_simp";

   329 val asm_lrN = "asm_lr";

   332 (* conversions *)

   334 local

   336 fun conv_mode x =

   337   ((Args.parens (Args.$$$ no_asmN) >> K simplify ||

   338     Args.parens (Args.$$$ no_asm_simpN) >> K asm_simplify ||

   339     Args.parens (Args.$$$ no_asm_useN) >> K full_simplify ||

   340     Scan.succeed asm_full_simplify) |> Scan.lift) x;

   342 in

   344 val simplified =

   345   Attrib.syntax (conv_mode -- Attrib.thms >> (fn (f, ths) => Thm.rule_attribute (fn x =>

   346     f ((if null ths then I else MetaSimplifier.clear_ss) (get_ss x) addsimps ths))));

   348 end;

   351 (* setup attributes *)

   353 val _ = Context.add_setup

   354  (Attrib.add_attributes

   355    [(simpN, Attrib.add_del_args simp_add simp_del, "declaration of Simplifier rule"),

   356     (congN, Attrib.add_del_args cong_add cong_del, "declaration of Simplifier congruence rule"),

   357     ("simplified", simplified, "simplified rule")]);

   361 (** proof methods **)

   363 (* simplification *)

   365 val simp_options =

   366  (Args.parens (Args.$$$ no_asmN) >> K simp_tac ||

   367   Args.parens (Args.$$$ no_asm_simpN) >> K asm_simp_tac ||

   368   Args.parens (Args.$$$ no_asm_useN) >> K full_simp_tac ||

   369   Args.parens (Args.$$$ asm_lrN) >> K asm_lr_simp_tac ||

   370   Scan.succeed asm_full_simp_tac);

   372 fun simp_flags x = (Scan.repeat

   373   (Args.parens (Args.$$$ "depth_limit" -- Args.colon |-- Args.nat)

   374     >> setmp MetaSimplifier.simp_depth_limit)

   375   >> (curry (Library.foldl op o) I o rev)) x;

   377 val cong_modifiers =

   378  [Args.$$$ congN -- Args.colon >> K ((I, cong_add): Method.modifier),

   379   Args.$$$ congN -- Args.add -- Args.colon >> K (I, cong_add),

   380   Args.$$$ congN -- Args.del -- Args.colon >> K (I, cong_del)];

   382 val simp_modifiers =

   383  [Args.$$$ simpN -- Args.colon >> K (I, simp_add),

   384   Args.$$$ simpN -- Args.add -- Args.colon >> K (I, simp_add),

   385   Args.$$$ simpN -- Args.del -- Args.colon >> K (I, simp_del),

   386   Args.$$$ simpN -- Args.$$$ onlyN -- Args.colon

   387     >> K (LocalSimpset.map MetaSimplifier.clear_ss, simp_add)]

   388    @ cong_modifiers;

   390 val simp_modifiers' =

   391  [Args.add -- Args.colon >> K (I, simp_add),

   392   Args.del -- Args.colon >> K (I, simp_del),

   393   Args.$$$ onlyN -- Args.colon

   394     >> K (LocalSimpset.map MetaSimplifier.clear_ss, simp_add)]

   395    @ cong_modifiers;

   397 fun simp_args more_mods =

   398   Method.sectioned_args (Args.bang_facts -- Scan.lift simp_options -- Scan.lift simp_flags)

   399     (more_mods @ simp_modifiers');

   401 fun simp_method ((prems, tac), FLAGS) ctxt = Method.METHOD (fn facts =>

   402   ALLGOALS (Method.insert_tac (prems @ facts)) THEN

   403     (FLAGS o CHANGED_PROP o ALLGOALS o tac) (local_simpset_of ctxt));

   405 fun simp_method' ((prems, tac), FLAGS) ctxt = Method.METHOD (fn facts =>

   406   HEADGOAL (Method.insert_tac (prems @ facts) THEN'

   407       ((FLAGS o CHANGED_PROP) oo tac) (local_simpset_of ctxt)));

   411 (** setup **)

   413 fun method_setup more_mods = Method.add_methods

   414  [(simpN, simp_args more_mods simp_method', "simplification"),

   415   ("simp_all", simp_args more_mods simp_method, "simplification (all goals)")];

   417 fun easy_setup reflect trivs = method_setup [] #> (fn thy =>

   418   let

   419     val trivialities = Drule.reflexive_thm :: trivs;

   421     fun unsafe_solver_tac prems = FIRST' [resolve_tac (trivialities @ prems), assume_tac];

   422     val unsafe_solver = mk_solver "easy unsafe" unsafe_solver_tac;

   424     (*no premature instantiation of variables during simplification*)

   425     fun safe_solver_tac prems = FIRST' [match_tac (trivialities @ prems), eq_assume_tac];

   426     val safe_solver = mk_solver "easy safe" safe_solver_tac;

   428     fun mk_eq thm =

   429       if can Logic.dest_equals (Thm.concl_of thm) then [thm]

   430       else [thm RS reflect] handle THM _ => [];

   432     fun mksimps thm = mk_eq (Drule.forall_elim_vars (#maxidx (Thm.rep_thm thm) + 1) thm);

   433   in

   434     GlobalSimpset.get thy :=

   435       empty_ss setsubgoaler asm_simp_tac

   436       setSSolver safe_solver

   437       setSolver unsafe_solver

   438       setmksimps mksimps;

   439     thy

   440   end);

   442 end;

   444 structure BasicSimplifier: BASIC_SIMPLIFIER = Simplifier;

   445 open BasicSimplifier;

author	wenzelm
	Thu Jul 05 20:01:35 2007 +0200 (2007-07-05)
changeset 23598	e03a43b8178c
parent 23536	60a1672e298e
child 23655	d2d1138e0ddc
permissions	-rw-r--r--