isabelle: src/Pure/simplifier.ML@33da3a55c00e

     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 -> 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;

    85 structure Simplifier: SIMPLIFIER =

    86 struct

    88 open MetaSimplifier;

    91 (** simpset data **)

    93 (* global simpsets *)

    95 structure GlobalSimpset = TheoryDataFun

    96 (struct

    97   val name = "Pure/simpset";

    98   type T = simpset ref;

   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);

   107 val _ = Context.add_setup GlobalSimpset.init;

   108 val print_simpset = GlobalSimpset.print;

   109 val get_simpset = ! o GlobalSimpset.get;

   111 val change_simpset_of = change o GlobalSimpset.get;

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

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

   115 val simpset = simpset_of o ML_Context.the_context;

   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;

   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);

   129 (* local simpsets *)

   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);

   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;

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

   146 val _ = ML_Context.value_antiq "simpset"

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

   150 (* generic simpsets *)

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

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

   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);

   159 (* attributes *)

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

   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);

   170 (** named simprocs **)

   172 fun err_dup_simprocs ds =

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

   175 (* data *)

   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;

   190 (* get simprocs *)

   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;

   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)));

   207 (* define simprocs *)

   209 local

   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));

   216 (* FIXME *)

   217 fun cert_terms ctxt ts = map (ProofContext.cert_term ctxt) ts;

   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;

   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;

   250 in

   252 val def_simproc = gen_simproc read_terms;

   253 val def_simproc_i = gen_simproc cert_terms;

   255 end;

   259 (** simplification tactics and rules **)

   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;

   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));

   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;

   280 local

   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;

   289 in

   291 val simp_thm = simp MetaSimplifier.rewrite_thm;

   292 val simp_cterm = simp MetaSimplifier.rewrite_cterm;

   294 end;

   297 (* tactics *)

   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);

   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;

   314 (* conversions *)

   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);

   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);

   330 (** concrete syntax of attributes **)

   332 (* add / del *)

   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";

   345 (* conversions *)

   347 local

   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;

   355 in

   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))));

   361 end;

   364 (* setup attributes *)

   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")]);

   374 (** proof methods **)

   376 (* simplification *)

   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);

   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;

   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)];

   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;

   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;

   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');

   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));

   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)));

   424 (** setup **)

   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)")];

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

   431   let

   432     val trivialities = Drule.reflexive_thm :: trivs;

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

   435     val unsafe_solver = mk_solver "easy unsafe" unsafe_solver_tac;

   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;

   441     fun mk_eq thm =

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

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

   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);

   455 end;

   457 structure BasicSimplifier: BASIC_SIMPLIFIER = Simplifier;

   458 open BasicSimplifier;

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--