src/Pure/Isar/isar_thy.ML
author wenzelm
Thu Jul 01 21:27:46 1999 +0200 (1999-07-01 ago)
changeset 6879 70f8c0c34b8d
parent 6850 da8a4660fb0c
child 6885 1dcac1789759
permissions -rw-r--r--
added with_facts(_i);
also, finally: opt_rules;
     1 (*  Title:      Pure/Isar/isar_thy.ML
     2     ID:         $Id$
     3     Author:     Markus Wenzel, TU Muenchen
     4 
     5 Pure/Isar derived theory operations.
     6 *)
     7 
     8 signature ISAR_THY =
     9 sig
    10   val add_text: Comment.text -> theory -> theory
    11   val add_title: Comment.text -> Comment.text -> Comment.text -> theory -> theory
    12   val add_chapter: Comment.text -> theory -> theory
    13   val add_section: Comment.text -> theory -> theory
    14   val add_subsection: Comment.text -> theory -> theory
    15   val add_subsubsection: Comment.text -> theory -> theory
    16   val add_classes: (bclass * xclass list) list * Comment.text -> theory -> theory
    17   val add_classes_i: (bclass * class list) list * Comment.text  -> theory -> theory
    18   val add_classrel: (xclass * xclass) * Comment.text -> theory -> theory
    19   val add_classrel_i: (class * class) * Comment.text -> theory -> theory
    20   val add_defsort: xsort * Comment.text -> theory -> theory
    21   val add_defsort_i: sort * Comment.text -> theory -> theory
    22   val add_nonterminals: (bstring * Comment.text) list -> theory -> theory
    23   val add_tyabbrs: ((bstring * string list * string * mixfix) * Comment.text) list
    24     -> theory -> theory
    25   val add_tyabbrs_i: ((bstring * string list * typ * mixfix) * Comment.text) list
    26     -> theory -> theory
    27   val add_arities: ((xstring * xsort list * xsort) * Comment.text) list -> theory -> theory
    28   val add_arities_i: ((string * sort list * sort) * Comment.text) list -> theory -> theory
    29   val add_typedecl: (bstring * string list * mixfix) * Comment.text -> theory -> theory
    30   val add_consts: ((bstring * string * mixfix) * Comment.text) list -> theory -> theory
    31   val add_consts_i: ((bstring * typ * mixfix) * Comment.text) list -> theory -> theory
    32   val add_modesyntax: string * bool -> ((bstring * string * mixfix) * Comment.text) list
    33     -> theory -> theory
    34   val add_modesyntax_i: string * bool -> ((bstring * typ * mixfix) * Comment.text) list
    35     -> theory -> theory
    36   val add_trrules: ((xstring * string) Syntax.trrule * Comment.text) list -> theory -> theory
    37   val add_trrules_i: (Syntax.ast Syntax.trrule * Comment.text) list -> theory -> theory
    38   val add_axioms: (((bstring * string) * Args.src list) * Comment.text) list -> theory -> theory
    39   val add_axioms_i: (((bstring * term) * theory attribute list) * Comment.text) list
    40     -> theory -> theory
    41   val add_defs: (((bstring * string) * Args.src list) * Comment.text) list -> theory -> theory
    42   val add_defs_i: (((bstring * term) * theory attribute list) * Comment.text) list
    43     -> theory -> theory
    44   val add_constdefs: (((bstring * string * mixfix) * Comment.text) * (string * Comment.text)) list
    45     -> theory -> theory
    46   val add_constdefs_i: (((bstring * typ * mixfix) * Comment.text) * (term * Comment.text)) list
    47     -> theory -> theory
    48   val apply_theorems: (xstring * Args.src list) list -> theory -> theory * thm list
    49   val apply_theorems_i: (thm * theory attribute list) list -> theory -> theory * thm list
    50   val have_theorems: ((bstring * Args.src list) * (xstring * Args.src list) list) * Comment.text
    51     -> theory -> theory
    52   val have_theorems_i: ((bstring * theory attribute list) * (thm * theory attribute list) list)
    53     * Comment.text -> theory -> theory
    54   val have_lemmas: ((bstring * Args.src list) * (xstring * Args.src list) list) * Comment.text
    55     -> theory -> theory
    56   val have_lemmas_i: ((bstring * theory attribute list) * (thm * theory attribute list) list)
    57     * Comment.text -> theory -> theory
    58   val have_facts: ((string * Args.src list) * (string * Args.src list) list) * Comment.text
    59     -> ProofHistory.T -> ProofHistory.T
    60   val have_facts_i: ((string * Proof.context attribute list) *
    61     (thm * Proof.context attribute list) list) * Comment.text -> ProofHistory.T -> ProofHistory.T
    62   val from_facts: (string * Args.src list) list * Comment.text -> ProofHistory.T -> ProofHistory.T
    63   val from_facts_i: (thm * Proof.context attribute list) list * Comment.text
    64     -> ProofHistory.T -> ProofHistory.T
    65   val with_facts: (string * Args.src list) list * Comment.text -> ProofHistory.T -> ProofHistory.T
    66   val with_facts_i: (thm * Proof.context attribute list) list * Comment.text
    67     -> ProofHistory.T -> ProofHistory.T
    68   val chain: Comment.text -> ProofHistory.T -> ProofHistory.T
    69   val fix: (string * string option) list * Comment.text -> ProofHistory.T -> ProofHistory.T
    70   val fix_i: (string * typ) list * Comment.text -> ProofHistory.T -> ProofHistory.T
    71   val match_bind: ((string list * string) * Comment.text) list -> ProofHistory.T -> ProofHistory.T
    72   val match_bind_i: ((term list * term) * Comment.text) list -> ProofHistory.T -> ProofHistory.T
    73   val theorem: (bstring * Args.src list * (string * string list)) * Comment.text
    74     -> bool -> theory -> ProofHistory.T
    75   val theorem_i: (bstring * theory attribute list * (term * term list)) * Comment.text
    76     -> bool -> theory -> ProofHistory.T
    77   val lemma: (bstring * Args.src list * (string * string list)) * Comment.text
    78     -> bool -> theory -> ProofHistory.T
    79   val lemma_i: (bstring * theory attribute list * (term * term list)) * Comment.text
    80     -> bool -> theory -> ProofHistory.T
    81   val assume: (string * Args.src list * (string * string list) list) * Comment.text
    82     -> ProofHistory.T -> ProofHistory.T
    83   val assume_i: (string * Proof.context attribute list * (term * term list) list) * Comment.text
    84     -> ProofHistory.T -> ProofHistory.T
    85   val presume: (string * Args.src list * (string * string list) list) * Comment.text
    86     -> ProofHistory.T -> ProofHistory.T
    87   val presume_i: (string * Proof.context attribute list * (term * term list) list) * Comment.text
    88     -> ProofHistory.T -> ProofHistory.T
    89   val show: (string * Args.src list * (string * string list)) * Comment.text
    90     -> ProofHistory.T -> ProofHistory.T
    91   val show_i: (string * Proof.context attribute list * (term * term list)) * Comment.text
    92     -> ProofHistory.T -> ProofHistory.T
    93   val have: (string * Args.src list * (string * string list)) * Comment.text
    94     -> ProofHistory.T -> ProofHistory.T
    95   val have_i: (string * Proof.context attribute list * (term * term list)) * Comment.text
    96     -> ProofHistory.T -> ProofHistory.T
    97   val thus: (string * Args.src list * (string * string list)) * Comment.text
    98     -> ProofHistory.T -> ProofHistory.T
    99   val thus_i: (string * Proof.context attribute list * (term * term list)) * Comment.text
   100     -> ProofHistory.T -> ProofHistory.T
   101   val hence: (string * Args.src list * (string * string list)) * Comment.text
   102     -> ProofHistory.T -> ProofHistory.T
   103   val hence_i: (string * Proof.context attribute list * (term * term list)) * Comment.text
   104     -> ProofHistory.T -> ProofHistory.T
   105   val begin_block: ProofHistory.T -> ProofHistory.T
   106   val next_block: ProofHistory.T -> ProofHistory.T
   107   val end_block: ProofHistory.T -> ProofHistory.T
   108   val tac: Method.text -> ProofHistory.T -> ProofHistory.T
   109   val then_tac: Method.text -> ProofHistory.T -> ProofHistory.T
   110   val proof: Comment.interest * (Method.text * Comment.interest) option
   111     -> ProofHistory.T -> ProofHistory.T
   112   val kill_proof: ProofHistory.T -> theory
   113   val global_qed_with: bstring option * Args.src list option
   114     -> (Method.text * Comment.interest) option
   115     -> Toplevel.transition -> Toplevel.transition
   116   val global_qed_with_i: bstring option * theory attribute list option
   117     -> (Method.text * Comment.interest) option
   118     -> Toplevel.transition -> Toplevel.transition
   119   val qed: (Method.text * Comment.interest) option -> Toplevel.transition -> Toplevel.transition
   120   val terminal_proof: Method.text * Comment.interest -> Toplevel.transition -> Toplevel.transition
   121   val immediate_proof: Toplevel.transition -> Toplevel.transition
   122   val default_proof: Toplevel.transition -> Toplevel.transition
   123   val also: ((string * Args.src list) list * Comment.interest) option * Comment.text
   124     -> Toplevel.transition -> Toplevel.transition
   125   val also_i: (thm list * Comment.interest) option * Comment.text
   126     -> Toplevel.transition -> Toplevel.transition
   127   val finally: ((string * Args.src list) list * Comment.interest) option * Comment.text
   128     -> Toplevel.transition -> Toplevel.transition
   129   val finally_i: (thm list * Comment.interest) option * Comment.text
   130     -> Toplevel.transition -> Toplevel.transition
   131   val use_mltext: string -> theory option -> theory option
   132   val use_mltext_theory: string -> theory -> theory
   133   val use_setup: string -> theory -> theory
   134   val parse_ast_translation: string -> theory -> theory
   135   val parse_translation: string -> theory -> theory
   136   val print_translation: string -> theory -> theory
   137   val typed_print_translation: string -> theory -> theory
   138   val print_ast_translation: string -> theory -> theory
   139   val token_translation: string -> theory -> theory
   140   val add_oracle: (bstring * string) * Comment.text -> theory -> theory
   141   val begin_theory: string -> string list -> (string * bool) list -> theory
   142   val end_theory: theory -> theory
   143   val theory: string * string list * (string * bool) list
   144     -> Toplevel.transition -> Toplevel.transition
   145   val context: string -> Toplevel.transition -> Toplevel.transition
   146   val update_context: string -> Toplevel.transition -> Toplevel.transition
   147 end;
   148 
   149 structure IsarThy: ISAR_THY =
   150 struct
   151 
   152 
   153 (** derived theory and proof operations **)
   154 
   155 (* formal comments *)
   156 
   157 fun add_text comment thy = thy;
   158 fun add_title title author date thy = thy;
   159 val add_chapter = add_text;
   160 val add_section = add_text;
   161 val add_subsection = add_text;
   162 val add_subsubsection = add_text;
   163 
   164 
   165 (* signature and syntax *)
   166 
   167 val add_classes = Theory.add_classes o Comment.ignore;
   168 val add_classes_i = Theory.add_classes_i o Comment.ignore;
   169 val add_classrel = Theory.add_classrel o single o Comment.ignore;
   170 val add_classrel_i = Theory.add_classrel_i o single o Comment.ignore;
   171 val add_defsort = Theory.add_defsort o Comment.ignore;
   172 val add_defsort_i = Theory.add_defsort_i o Comment.ignore;
   173 val add_nonterminals = Theory.add_nonterminals o map Comment.ignore;
   174 val add_tyabbrs = Theory.add_tyabbrs o map Comment.ignore;
   175 val add_tyabbrs_i = Theory.add_tyabbrs_i o map Comment.ignore;
   176 val add_arities = Theory.add_arities o map Comment.ignore;
   177 val add_arities_i = Theory.add_arities_i o map Comment.ignore;
   178 val add_typedecl = PureThy.add_typedecls o single o Comment.ignore;
   179 val add_consts = Theory.add_consts o map Comment.ignore;
   180 val add_consts_i = Theory.add_consts_i o map Comment.ignore;
   181 fun add_modesyntax mode = Theory.add_modesyntax mode o map Comment.ignore;
   182 fun add_modesyntax_i mode = Theory.add_modesyntax_i mode o map Comment.ignore;
   183 val add_trrules = Theory.add_trrules o map Comment.ignore;
   184 val add_trrules_i = Theory.add_trrules_i o map Comment.ignore;
   185 
   186 
   187 
   188 (* axioms and defs *)
   189 
   190 fun add_axms f args thy =
   191   f (map (fn (x, srcs) => (x, map (Attrib.global_attribute thy) srcs)) args) thy;
   192 
   193 val add_axioms = add_axms PureThy.add_axioms o map Comment.ignore;
   194 val add_axioms_i = PureThy.add_axioms_i o map Comment.ignore;
   195 val add_defs = add_axms PureThy.add_defs o map Comment.ignore;
   196 val add_defs_i = PureThy.add_defs_i o map Comment.ignore;
   197 
   198 
   199 (* constdefs *)
   200 
   201 fun gen_add_constdefs consts defs args thy =
   202   thy
   203   |> consts (map (Comment.ignore o fst) args)
   204   |> defs (map (fn (((c, _, mx), _), (s, _)) =>
   205     (((Thm.def_name (Syntax.const_name c mx), s), []), Comment.none)) args);
   206 
   207 fun add_constdefs args = gen_add_constdefs Theory.add_consts add_defs args;
   208 fun add_constdefs_i args = gen_add_constdefs Theory.add_consts_i add_defs_i args;
   209 
   210 
   211 (* theorems *)
   212 
   213 fun gen_have_thmss get attrib f ((name, more_srcs), th_srcs) x =
   214   f name (map (attrib x) more_srcs)
   215     (map (fn (s, srcs) => (get x s, map (attrib x) srcs)) th_srcs) x;
   216 
   217 fun global_have_thmss x = gen_have_thmss PureThy.get_thms Attrib.global_attribute x;
   218 
   219 fun local_have_thmss x =
   220   gen_have_thmss (ProofContext.get_thms o Proof.context_of)
   221     (Attrib.local_attribute o Proof.theory_of) x;
   222 
   223 fun have_thmss_i f ((name, more_atts), th_atts) =
   224   f name more_atts (map (apfst single) th_atts);
   225 
   226 fun have_lemss name atts = PureThy.have_thmss name (atts @ [Drule.tag_lemma]);
   227 
   228 
   229 fun apply_theorems th_srcs = global_have_thmss PureThy.have_thmss ((None, []), th_srcs);
   230 fun apply_theorems_i th_srcs = have_thmss_i PureThy.have_thmss ((None, []), th_srcs);
   231 val have_theorems = #1 oo (global_have_thmss (PureThy.have_thmss o Some) o Comment.ignore);
   232 val have_theorems_i = #1 oo (have_thmss_i (PureThy.have_thmss o Some) o Comment.ignore);
   233 val have_lemmas = #1 oo (global_have_thmss (have_lemss o Some) o Comment.ignore);
   234 val have_lemmas_i = #1 oo (have_thmss_i (have_lemss o Some) o Comment.ignore);
   235 val have_facts = ProofHistory.apply o local_have_thmss (Proof.have_thmss []) o Comment.ignore;
   236 val have_facts_i = ProofHistory.apply o have_thmss_i (Proof.have_thmss []) o Comment.ignore;
   237 
   238 
   239 (* forward chaining *)
   240 
   241 fun gen_from_facts f = ProofHistory.apply o (Proof.chain oo curry f ("", []));
   242 
   243 fun add_thmss name atts ths_atts state =
   244   Proof.have_thmss (Proof.the_facts state) name atts ths_atts state;
   245 
   246 val from_facts = gen_from_facts (local_have_thmss (Proof.have_thmss [])) o Comment.ignore;
   247 val from_facts_i = gen_from_facts (have_thmss_i (Proof.have_thmss [])) o Comment.ignore;
   248 val with_facts = gen_from_facts (local_have_thmss add_thmss) o Comment.ignore;
   249 val with_facts_i = gen_from_facts (have_thmss_i add_thmss) o Comment.ignore;
   250 
   251 fun chain comment_ignore = ProofHistory.apply Proof.chain;
   252 
   253 
   254 (* context *)
   255 
   256 val fix = ProofHistory.apply o Proof.fix o Comment.ignore;
   257 val fix_i = ProofHistory.apply o Proof.fix_i o Comment.ignore;
   258 val match_bind = ProofHistory.apply o Proof.match_bind o map Comment.ignore;
   259 val match_bind_i = ProofHistory.apply o Proof.match_bind_i o map Comment.ignore;
   260 
   261 
   262 (* statements *)
   263 
   264 fun global_statement f (name, src, s) int thy =
   265   ProofHistory.init (Toplevel.undo_limit int)
   266     (f name (map (Attrib.global_attribute thy) src) s thy);
   267 
   268 fun global_statement_i f (name, atts, t) int thy =
   269   ProofHistory.init (Toplevel.undo_limit int) (f name atts t thy);
   270 
   271 fun local_statement do_open f g (name, src, s) = ProofHistory.apply_cond_open do_open (fn state =>
   272   f name (map (Attrib.local_attribute (Proof.theory_of state)) src) s (g state));
   273 
   274 fun local_statement_i do_open f g (name, atts, t) =
   275   ProofHistory.apply_cond_open do_open (f name atts t o g);
   276 
   277 val theorem   = global_statement Proof.theorem o Comment.ignore;
   278 val theorem_i = global_statement_i Proof.theorem_i o Comment.ignore;
   279 val lemma     = global_statement Proof.lemma o Comment.ignore;
   280 val lemma_i   = global_statement_i Proof.lemma_i o Comment.ignore;
   281 val assume    = local_statement false (Proof.assume assume_tac) I o Comment.ignore;
   282 val assume_i  = local_statement_i false (Proof.assume_i assume_tac) I o Comment.ignore;
   283 val presume   = local_statement false (Proof.assume (K all_tac)) I o Comment.ignore;
   284 val presume_i = local_statement_i false (Proof.assume_i (K all_tac)) I o Comment.ignore;
   285 val show      = local_statement true Proof.show I o Comment.ignore;
   286 val show_i    = local_statement_i true Proof.show_i I o Comment.ignore;
   287 val have      = local_statement true Proof.have I o Comment.ignore;
   288 val have_i    = local_statement_i true Proof.have_i I o Comment.ignore;
   289 val thus      = local_statement true Proof.show Proof.chain o Comment.ignore;
   290 val thus_i    = local_statement_i true Proof.show_i Proof.chain o Comment.ignore;
   291 val hence     = local_statement true Proof.have Proof.chain o Comment.ignore;
   292 val hence_i   = local_statement_i true Proof.have_i Proof.chain o Comment.ignore;
   293 
   294 
   295 (* blocks *)
   296 
   297 val begin_block = ProofHistory.apply_open Proof.begin_block;
   298 val next_block = ProofHistory.apply Proof.next_block;
   299 val end_block = ProofHistory.apply_close Proof.end_block;
   300 
   301 
   302 (* backward steps *)
   303 
   304 val tac = ProofHistory.applys o Method.tac;
   305 val then_tac = ProofHistory.applys o Method.then_tac;
   306 
   307 val proof =
   308   ProofHistory.applys o Method.proof o apsome Comment.ignore_interest o Comment.ignore_interest';
   309 
   310 
   311 (* print result *)
   312 
   313 fun pretty_result {kind, name, thm} =
   314   Pretty.block [Pretty.str (kind ^ " " ^ name ^ ":"), Pretty.fbrk, Display.pretty_thm thm];
   315 
   316 val print_result = Pretty.writeln o pretty_result;
   317 fun cond_print_result int res = if int then print_result res else ();
   318 
   319 fun proof'' f = Toplevel.proof' (f o cond_print_result);
   320 
   321 
   322 (* local endings *)
   323 
   324 val local_qed =
   325   proof'' o (ProofHistory.applys_close oo Method.local_qed) o apsome Comment.ignore_interest;
   326 
   327 val local_terminal_proof =
   328   proof'' o (ProofHistory.applys_close oo Method.local_terminal_proof) o Comment.ignore_interest;
   329 
   330 val local_immediate_proof = proof'' (ProofHistory.applys_close o Method.local_immediate_proof);
   331 val local_default_proof = proof'' (ProofHistory.applys_close o Method.local_default_proof);
   332 
   333 
   334 (* global endings *)
   335 
   336 val kill_proof = Proof.theory_of o ProofHistory.current;
   337 
   338 fun global_result finish = Toplevel.proof_to_theory (fn prf =>
   339   let
   340     val state = ProofHistory.current prf;
   341     val _ = if Proof.at_bottom state then () else raise Toplevel.UNDEF;
   342     val (thy, res) = finish state;
   343   in print_result res; thy end);
   344 
   345 fun gen_global_qed_with prep_att (alt_name, raw_atts) meth state =
   346   let
   347     val thy = Proof.theory_of state;
   348     val alt_atts = apsome (map (prep_att thy)) raw_atts;
   349   in Method.global_qed alt_name alt_atts (apsome Comment.ignore_interest meth) state end;
   350 
   351 val global_qed_with = global_result oo gen_global_qed_with Attrib.global_attribute;
   352 val global_qed_with_i = global_result oo gen_global_qed_with (K I);
   353 val global_qed = global_qed_with (None, None);
   354 
   355 val global_terminal_proof = global_result o Method.global_terminal_proof o Comment.ignore_interest;
   356 val global_immediate_proof = global_result Method.global_immediate_proof;
   357 val global_default_proof = global_result Method.global_default_proof;
   358 
   359 
   360 (* common endings *)
   361 
   362 fun qed meth = local_qed meth o global_qed meth;
   363 fun terminal_proof meth = local_terminal_proof meth o global_terminal_proof meth;
   364 val immediate_proof = local_immediate_proof o global_immediate_proof;
   365 val default_proof = local_default_proof o global_default_proof;
   366 
   367 
   368 (* calculational proof commands *)
   369 
   370 local
   371 
   372 fun cond_print_calc int thm =
   373   if int then Pretty.writeln (Pretty.big_list "calculation:" [Display.pretty_thm thm])
   374   else ();
   375 
   376 fun proof''' f = Toplevel.proof' (f o cond_print_calc);
   377 
   378 fun get_thmss srcs = Proof.the_facts o local_have_thmss (Proof.have_thmss []) (("", []), srcs); 
   379 fun get_thmss_i thms _ = thms;
   380 
   381 fun gen_calc get f (args, _) prt state =
   382   f (apsome (fn (srcs, _) => get srcs state) args) prt state;
   383 
   384 in
   385 
   386 fun also x = proof''' (ProofHistory.applys o gen_calc get_thmss Calculation.also x);
   387 fun also_i x = proof''' (ProofHistory.applys o gen_calc get_thmss_i Calculation.also x);
   388 fun finally x = proof''' (ProofHistory.applys o gen_calc get_thmss Calculation.finally x);
   389 fun finally_i x = proof''' (ProofHistory.applys o gen_calc get_thmss_i Calculation.finally x);
   390 
   391 end;
   392 
   393 
   394 (* use ML text *)
   395 
   396 fun use_mltext txt opt_thy = #2 (Context.pass opt_thy (use_text false) txt);
   397 fun use_mltext_theory txt thy = #2 (Context.pass_theory thy (use_text false) txt);
   398 
   399 fun use_context txt = use_mltext_theory ("Context.>> (" ^ txt ^ ");");
   400 
   401 fun use_let name body txt =
   402   use_context ("let val " ^ name ^ " = " ^ txt ^ " in\n" ^ body ^ " end");
   403 
   404 val use_setup =
   405   use_let "setup: (theory -> theory) list" "Library.apply setup";
   406 
   407 
   408 (* translation functions *)
   409 
   410 val parse_ast_translation =
   411   use_let "parse_ast_translation: (string * (Syntax.ast list -> Syntax.ast)) list"
   412     "Theory.add_trfuns (parse_ast_translation, [], [], [])";
   413 
   414 val parse_translation =
   415   use_let "parse_translation: (string * (term list -> term)) list"
   416     "Theory.add_trfuns ([], parse_translation, [], [])";
   417 
   418 val print_translation =
   419   use_let "print_translation: (string * (term list -> term)) list"
   420     "Theory.add_trfuns ([], [], print_translation, [])";
   421 
   422 val print_ast_translation =
   423   use_let "print_ast_translation: (string * (Syntax.ast list -> Syntax.ast)) list"
   424     "Theory.add_trfuns ([], [], [], print_ast_translation)";
   425 
   426 val typed_print_translation =
   427   use_let "typed_print_translation: (string * (bool -> typ -> term list -> term)) list"
   428     "Theory.add_trfunsT typed_print_translation";
   429 
   430 val token_translation =
   431   use_let "token_translation: (string * string * (string -> string * int)) list"
   432     "Theory.add_tokentrfuns token_translation";
   433 
   434 
   435 (* add_oracle *)
   436 
   437 fun add_oracle ((name, txt), comment_ignore) =
   438   use_let
   439     "oracle: bstring * (Sign.sg * Object.T -> term)"
   440     "Theory.add_oracle oracle"
   441     ("(" ^ quote name ^ ", " ^ txt ^ ")");
   442 
   443 
   444 (* theory init and exit *)
   445 
   446 fun begin_theory name parents files =
   447   let
   448     val paths = map (apfst Path.unpack) files;
   449     val thy = ThyInfo.begin_theory name parents paths;
   450   in Present.begin_theory name parents paths thy end;
   451 
   452 fun end_theory thy =
   453   (Present.end_theory (PureThy.get_name thy); ThyInfo.end_theory thy);
   454 
   455 fun kill_theory thy = ThyInfo.remove_thy (PureThy.get_name thy);
   456 
   457 fun bg_theory (name, parents, files) () = begin_theory name parents files;
   458 fun en_theory thy = (end_theory thy; ());
   459 
   460 fun theory spec = Toplevel.init_theory (bg_theory spec) en_theory kill_theory;
   461 
   462 
   463 (* context switch *)
   464 
   465 fun switch_theory load s =
   466   Toplevel.init_theory (fn () => (the (#2 (Context.pass None load s)))) (K ()) (K ());
   467 
   468 val context = switch_theory ThyInfo.use_thy;
   469 val update_context = switch_theory ThyInfo.update_thy;
   470 
   471 
   472 end;