src/Pure/sign.ML
author wenzelm
Sat Nov 24 16:55:56 2001 +0100 (2001-11-24)
changeset 12284 131e743d168a
parent 12123 739eba13e2cd
child 12286 fe218fdc961a
permissions -rw-r--r--
added gen_merge_lists(') and merge_lists(');
removed obsolete generic_extend, generic_merge, extend_list;
     1 (*  Title:      Pure/sign.ML
     2     ID:         $Id$
     3     Author:     Lawrence C Paulson and Markus Wenzel
     4 
     5 The abstract type "sg" of signatures.
     6 *)
     7 
     8 (*base names*)
     9 type bstring = string;
    10 type bclass = class;
    11 (*external forms -- partially qualified names*)
    12 type xstring = string;
    13 type xclass = class;
    14 type xsort = sort;
    15 type xtyp = typ;
    16 type xterm = term;
    17 
    18 signature SIGN =
    19 sig
    20   type sg
    21   type sg_ref
    22   type data
    23   val rep_sg: sg ->
    24    {self: sg_ref,
    25     tsig: Type.type_sig,
    26     const_tab: typ Symtab.table,
    27     syn: Syntax.syntax,
    28     path: string list option,
    29     spaces: (string * NameSpace.T) list,
    30     data: data}
    31   val name_of: sg -> string
    32   val stamp_names_of: sg -> string list
    33   val exists_stamp: string -> sg -> bool
    34   val tsig_of: sg -> Type.type_sig
    35   val deref: sg_ref -> sg
    36   val self_ref: sg -> sg_ref
    37   val subsig: sg * sg -> bool
    38   val joinable: sg * sg -> bool
    39   val eq_sg: sg * sg -> bool
    40   val same_sg: sg * sg -> bool
    41   val is_draft: sg -> bool
    42   val is_stale: sg -> bool
    43   val const_type: sg -> string -> typ option
    44   val classes: sg -> class list
    45   val defaultS: sg -> sort
    46   val subsort: sg -> sort * sort -> bool
    47   val nodup_vars: term -> term
    48   val norm_sort: sg -> sort -> sort
    49   val of_sort: sg -> typ * sort -> bool
    50   val witness_sorts: sg -> sort list -> sort list -> (typ * sort) list
    51   val univ_witness: sg -> (typ * sort) option
    52   val typ_instance: sg -> typ * typ -> bool
    53   val classK: string
    54   val typeK: string
    55   val constK: string
    56   val full_name: sg -> bstring -> string
    57   val full_name_path: sg -> string -> bstring -> string
    58   val base_name: string -> bstring
    59   val intern: sg -> string -> xstring -> string
    60   val extern: sg -> string -> string -> xstring
    61   val cond_extern: sg -> string -> string -> xstring
    62   val cond_extern_table: sg -> string -> 'a Symtab.table -> (xstring * 'a) list
    63   val intern_class: sg -> xclass -> class
    64   val intern_tycon: sg -> xstring -> string
    65   val intern_const: sg -> xstring -> string
    66   val intern_sort: sg -> xsort -> sort
    67   val intern_typ: sg -> xtyp -> typ
    68   val intern_term: sg -> xterm -> term
    69   val intern_tycons: sg -> xtyp -> typ
    70   val pretty_sg: sg -> Pretty.T
    71   val str_of_sg: sg -> string
    72   val pprint_sg: sg -> pprint_args -> unit
    73   val pretty_term: sg -> term -> Pretty.T
    74   val pretty_term': Syntax.syntax -> sg -> term -> Pretty.T
    75   val pretty_typ: sg -> typ -> Pretty.T
    76   val pretty_sort: sg -> sort -> Pretty.T
    77   val pretty_classrel: sg -> class * class -> Pretty.T
    78   val pretty_arity: sg -> string * sort list * sort -> Pretty.T
    79   val string_of_term: sg -> term -> string
    80   val string_of_typ: sg -> typ -> string
    81   val string_of_sort: sg -> sort -> string
    82   val str_of_sort: sg -> sort -> string
    83   val str_of_classrel: sg -> class * class -> string
    84   val str_of_arity: sg -> string * sort list * sort -> string
    85   val pprint_term: sg -> term -> pprint_args -> unit
    86   val pprint_typ: sg -> typ -> pprint_args -> unit
    87   val certify_class: sg -> class -> class
    88   val certify_sort: sg -> sort -> sort
    89   val certify_typ: sg -> typ -> typ
    90   val certify_typ_no_norm: sg -> typ -> typ
    91   val certify_tycon: sg -> string -> string
    92   val certify_tyabbr: sg -> string -> string
    93   val certify_tyname: sg -> string -> string
    94   val certify_const: sg -> string -> string
    95   val certify_term: sg -> term -> term * typ * int
    96   val read_sort: sg -> string -> sort
    97   val read_raw_typ: sg * (indexname -> sort option) -> string -> typ
    98   val read_typ: sg * (indexname -> sort option) -> string -> typ
    99   val read_typ': Syntax.syntax -> sg * (indexname -> sort option) -> string -> typ
   100   val read_typ_no_norm': Syntax.syntax -> sg * (indexname -> sort option) -> string -> typ
   101   val infer_types: sg -> (indexname -> typ option) ->
   102     (indexname -> sort option) -> string list -> bool
   103     -> xterm list * typ -> term * (indexname * typ) list
   104   val infer_types_simult: sg -> (indexname -> typ option) ->
   105     (indexname -> sort option) -> string list -> bool
   106     -> (xterm list * typ) list -> term list * (indexname * typ) list
   107   val read_def_terms':
   108     Syntax.syntax -> sg * (indexname -> typ option) * (indexname -> sort option) ->
   109     string list -> bool -> (string * typ) list -> term list * (indexname * typ) list
   110   val read_def_terms:
   111     sg * (indexname -> typ option) * (indexname -> sort option) ->
   112     string list -> bool -> (string * typ) list -> term list * (indexname * typ) list
   113   val simple_read_term: sg -> typ -> string -> term
   114   val add_classes: (bclass * xclass list) list -> sg -> sg
   115   val add_classes_i: (bclass * class list) list -> sg -> sg
   116   val add_classrel: (xclass * xclass) list -> sg -> sg
   117   val add_classrel_i: (class * class) list -> sg -> sg
   118   val add_defsort: string -> sg -> sg
   119   val add_defsort_i: sort -> sg -> sg
   120   val add_types: (bstring * int * mixfix) list -> sg -> sg
   121   val add_nonterminals: bstring list -> sg -> sg
   122   val add_tyabbrs: (bstring * string list * string * mixfix) list -> sg -> sg
   123   val add_tyabbrs_i: (bstring * string list * typ * mixfix) list -> sg -> sg
   124   val add_arities: (xstring * string list * string) list -> sg -> sg
   125   val add_arities_i: (string * sort list * sort) list -> sg -> sg
   126   val add_consts: (bstring * string * mixfix) list -> sg -> sg
   127   val add_consts_i: (bstring * typ * mixfix) list -> sg -> sg
   128   val add_syntax: (bstring * string * mixfix) list -> sg -> sg
   129   val add_syntax_i: (bstring * typ * mixfix) list -> sg -> sg
   130   val add_modesyntax: (string * bool) * (bstring * string * mixfix) list -> sg -> sg
   131   val add_modesyntax_i: (string * bool) * (bstring * typ * mixfix) list -> sg -> sg
   132   val add_trfuns:
   133     (string * (ast list -> ast)) list *
   134     (string * (term list -> term)) list *
   135     (string * (term list -> term)) list *
   136     (string * (ast list -> ast)) list -> sg -> sg
   137   val add_trfunsT:
   138     (string * (bool -> typ -> term list -> term)) list -> sg -> sg
   139   val add_tokentrfuns:
   140     (string * string * (string -> string * real)) list -> sg -> sg
   141   val add_trrules: (xstring * string) Syntax.trrule list -> sg -> sg
   142   val add_trrules_i: ast Syntax.trrule list -> sg -> sg
   143   val add_path: string -> sg -> sg
   144   val add_space: string * string list -> sg -> sg
   145   val hide_space: string * string list -> sg -> sg
   146   val hide_space_i: string * string list -> sg -> sg
   147   val add_name: string -> sg -> sg
   148   val data_kinds: data -> string list
   149   val merge_refs: sg_ref * sg_ref -> sg_ref
   150   val merge: sg * sg -> sg
   151   val copy: sg -> sg
   152   val finish: sg -> sg
   153   val prep_ext: sg -> sg
   154   val PureN: string
   155   val CPureN: string
   156   val nontriv_merge: sg * sg -> sg
   157   val pre_pure: sg
   158   val const_of_class: class -> string
   159   val class_of_const: string -> class
   160 end;
   161 
   162 signature PRIVATE_SIGN =
   163 sig
   164   include SIGN
   165   val init_data: Object.kind * (Object.T * (Object.T -> Object.T) * (Object.T -> Object.T) *
   166     (Object.T -> Object.T) * (Object.T * Object.T -> Object.T) * (sg -> Object.T -> unit))
   167     -> sg -> sg
   168   val get_data: Object.kind -> (Object.T -> 'a) -> sg -> 'a
   169   val put_data: Object.kind -> ('a -> Object.T) -> 'a -> sg -> sg
   170   val print_data: Object.kind -> sg -> unit
   171 end;
   172 
   173 structure Sign: PRIVATE_SIGN =
   174 struct
   175 
   176 
   177 (** datatype sg **)
   178 
   179 (* types sg, data, sg_ref *)
   180 
   181 datatype sg =
   182   Sg of
   183    {id: string ref,                             (*id*)
   184     stamps: string ref list} *                  (*unique theory indentifier*)
   185    {self: sg_ref,                               (*mutable self reference*)
   186     tsig: Type.type_sig,                        (*order-sorted signature of types*)
   187     const_tab: typ Symtab.table,                (*type schemes of constants*)
   188     syn: Syntax.syntax,                         (*syntax for parsing and printing*)
   189     path: string list option,                   (*current name space entry prefix*)
   190     spaces: (string * NameSpace.T) list,        (*name spaces for consts, types etc.*)
   191     data: data}                                 (*anytype data*)
   192 and data =
   193   Data of
   194     (Object.kind *                              (*kind (for authorization)*)
   195       (Object.T *                               (*value*)
   196         ((Object.T -> Object.T) *               (*copy method*)
   197           (Object.T -> Object.T) *              (*finish method*)
   198           (Object.T -> Object.T) *              (*prepare extend method*)
   199           (Object.T * Object.T -> Object.T) *   (*merge and prepare extend method*)
   200           (sg -> Object.T -> unit))))           (*print method*)
   201     Symtab.table
   202 and sg_ref =
   203   SgRef of sg ref option;
   204 
   205 (*make signature*)
   206 fun make_sign (id, self, tsig, const_tab, syn, path, spaces, data, stamps) =
   207   Sg ({id = id, stamps = stamps}, {self = self, tsig = tsig, const_tab = const_tab,
   208     syn = syn, path = path, spaces = spaces, data = data});
   209 
   210 
   211 (* basic operations *)
   212 
   213 fun rep_sg (Sg (_, args)) = args;
   214 
   215 (*show stamps*)
   216 fun stamp_names_of (Sg ({stamps, ...}, _)) = rev (map ! stamps);
   217 fun exists_stamp name (Sg ({stamps, ...}, _)) = exists (equal name o !) stamps;
   218 fun pretty_sg sg = Pretty.str_list "{" "}" (stamp_names_of sg);
   219 val str_of_sg = Pretty.str_of o pretty_sg;
   220 val pprint_sg = Pretty.pprint o pretty_sg;
   221 
   222 val tsig_of = #tsig o rep_sg;
   223 val syn_of = #syn o rep_sg;
   224 
   225 fun const_type (Sg (_, {const_tab, ...})) c = Symtab.lookup (const_tab, c);
   226 
   227 
   228 (* id and self *)
   229 
   230 fun check_stale (sg as Sg ({id, ...},
   231         {self = SgRef (Some (ref (Sg ({id = id', ...}, _)))), ...})) =
   232       if id = id' then sg
   233       else raise TERM ("Stale signature: " ^ str_of_sg sg, [])
   234   | check_stale _ = sys_error "Sign.check_stale";
   235 
   236 fun is_stale sg = (check_stale sg; false) handle TERM _ => true;
   237 
   238 fun self_ref (sg as Sg (_, {self, ...})) = (check_stale sg; self);
   239 
   240 fun deref (SgRef (Some (ref sg))) = sg
   241   | deref (SgRef None) = sys_error "Sign.deref";
   242 
   243 fun name_of (sg as Sg ({id = ref name, ...}, _)) =
   244   if name = "" orelse ord name = ord "#" then
   245     raise TERM ("Nameless signature " ^ str_of_sg sg, [])
   246   else name;
   247 
   248 
   249 (* inclusion and equality *)
   250 
   251 local
   252   (*avoiding polymorphic equality: factor 10 speedup*)
   253   fun mem_stamp (_:string ref, []) = false
   254     | mem_stamp (x, y :: ys) = x = y orelse mem_stamp (x, ys);
   255 
   256   fun subset_stamp ([], ys) = true
   257     | subset_stamp (x :: xs, ys) =
   258         mem_stamp (x, ys) andalso subset_stamp (xs, ys);
   259 
   260   (*fast partial test*)
   261   fun fast_sub ([]: string ref list, _) = true
   262     | fast_sub (_, []) = false
   263     | fast_sub (x :: xs, y :: ys) =
   264         if x = y then fast_sub (xs, ys)
   265         else fast_sub (x :: xs, ys);
   266 in
   267   fun eq_sg (sg1 as Sg ({id = id1, ...}, _), sg2 as Sg ({id = id2, ...}, _)) =
   268     (check_stale sg1; check_stale sg2; id1 = id2);
   269 
   270   fun subsig (sg1 as Sg ({stamps = s1, ...}, _), sg2 as Sg ({stamps = s2, ...}, _)) =
   271     eq_sg (sg1, sg2) orelse subset_stamp (s1, s2);
   272 
   273   fun fast_subsig (sg1 as Sg ({stamps = s1, ...}, _), sg2 as Sg ({stamps = s2, ...}, _)) =
   274     eq_sg (sg1, sg2) orelse fast_sub (s1, s2);
   275 end;
   276 
   277 
   278 fun joinable (sg1, sg2) = subsig (sg1, sg2) orelse subsig (sg2, sg1);
   279 
   280 (*test if same theory names are contained in signatures' stamps,
   281   i.e. if signatures belong to same theory but not necessarily to the
   282   same version of it*)
   283 fun same_sg (sg1 as Sg ({stamps = s1, ...}, _), sg2 as Sg ({stamps = s2, ...}, _)) =
   284   eq_sg (sg1, sg2) orelse eq_set_string (pairself (map (op !)) (s1, s2));
   285 
   286 (*test for drafts*)
   287 fun is_draft (Sg ({stamps = ref name :: _, ...}, _)) = name = "" orelse ord name = ord "#";
   288 
   289 
   290 (* classes and sorts *)
   291 
   292 val classes = Type.classes o tsig_of;
   293 val defaultS = Type.defaultS o tsig_of;
   294 val subsort = Type.subsort o tsig_of;
   295 val norm_sort = Type.norm_sort o tsig_of;
   296 val of_sort = Type.of_sort o tsig_of;
   297 val witness_sorts = Type.witness_sorts o tsig_of;
   298 val univ_witness = Type.univ_witness o tsig_of;
   299 fun typ_instance sg (T, U) = Type.typ_instance (tsig_of sg, T, U);
   300 
   301 
   302 (** signature data **)
   303 
   304 (* errors *)
   305 
   306 fun of_theory sg = "\nof theory " ^ str_of_sg sg;
   307 
   308 fun err_inconsistent kinds =
   309   error ("Attempt to merge different versions of " ^ commas_quote kinds ^ " data");
   310 
   311 fun err_method name kind e =
   312   (writeln ("Error while invoking " ^ quote kind ^ " " ^ name ^ " method"); raise e);
   313 
   314 fun err_dup_init sg kind =
   315   error ("Duplicate initialization of " ^ quote kind ^ " data" ^ of_theory sg);
   316 
   317 fun err_uninit sg kind =
   318   error ("Tried to access uninitialized " ^ quote kind ^ " data" ^
   319          of_theory sg);
   320 
   321 (*Trying to access theory data using get / put operations from a different
   322   instance of the TheoryDataFun result.  Typical cure: re-load all files*)
   323 fun err_access sg kind =
   324   error ("Unauthorized access to " ^ quote kind ^ " data" ^ of_theory sg);
   325 
   326 
   327 (* prepare data *)
   328 
   329 val empty_data = Data Symtab.empty;
   330 
   331 fun merge_data (Data tab1, Data tab2) =
   332   let
   333     val data1 = map snd (Symtab.dest tab1);
   334     val data2 = map snd (Symtab.dest tab2);
   335     val all_data = data1 @ data2;
   336     val kinds = gen_distinct Object.eq_kind (map fst all_data);
   337 
   338    fun entry data kind =
   339      (case gen_assoc Object.eq_kind (data, kind) of
   340        None => []
   341      | Some x => [(kind, x)]);
   342 
   343     fun merge_entries [(kind, (e, mths as (_, _, ext, _, _)))] =
   344           (kind, (ext e handle exn => err_method "prep_ext" (Object.name_of_kind kind) exn, mths))
   345       | merge_entries [(kind, (e1, mths as (_, _, _, mrg, _))), (_, (e2, _))] =
   346           (kind, (mrg (e1, e2)
   347             handle exn => err_method "merge" (Object.name_of_kind kind) exn, mths))
   348       | merge_entries _ = sys_error "merge_entries";
   349 
   350     val data = map (fn k => merge_entries (entry data1 k @ entry data2 k)) kinds;
   351     val data_idx = map (fn (k, x) => (Object.name_of_kind k, (k, x))) data;
   352   in
   353     Data (Symtab.make data_idx)
   354       handle Symtab.DUPS dups => err_inconsistent dups
   355   end;
   356 
   357 fun prep_ext_data data = merge_data (data, empty_data);
   358 
   359 fun init_data_sg sg (Data tab) kind e cp fin ext mrg prt =
   360   let val name = Object.name_of_kind kind in
   361     Data (Symtab.update_new ((name, (kind, (e, (cp, fin, ext, mrg, prt)))), tab))
   362       handle Symtab.DUP _ => err_dup_init sg name
   363   end;
   364 
   365 
   366 (* access data *)
   367 
   368 fun data_kinds (Data tab) = map fst (Symtab.dest tab);
   369 
   370 fun lookup_data sg tab kind =
   371   let val name = Object.name_of_kind kind in
   372     (case Symtab.lookup (tab, name) of
   373       Some (k, x) =>
   374         if Object.eq_kind (kind, k) then x
   375         else err_access sg name
   376     | None => err_uninit sg name)
   377   end;
   378 
   379 fun get_data kind f (sg as Sg (_, {data = Data tab, ...})) =
   380   let val x = fst (lookup_data sg tab kind)
   381   in f x handle Match => Object.kind_error kind end;
   382 
   383 fun print_data kind (sg as Sg (_, {data = Data tab, ...})) =
   384   let val (e, (_, _, _, _, prt)) = lookup_data sg tab kind
   385   in prt sg e handle exn => err_method ("print" ^ of_theory sg) (Object.name_of_kind kind) exn end;
   386 
   387 fun put_data_sg sg (Data tab) kind f x =
   388   Data (Symtab.update ((Object.name_of_kind kind,
   389     (kind, (f x, snd (lookup_data sg tab kind)))), tab));
   390 
   391 
   392 
   393 (** build signatures **)
   394 
   395 fun ext_stamps stamps (id as ref name) =
   396   let val stmps = (case stamps of ref "#" :: ss => ss | ss => ss) in
   397     if exists (equal name o !) stmps then
   398       error ("Theory already contains a " ^ quote name ^ " component")
   399     else id :: stmps
   400   end;
   401 
   402 fun create_sign self stamps name (syn, tsig, ctab, (path, spaces), data) =
   403   let
   404     val id = ref name;
   405     val sign =
   406       make_sign (id, self, tsig, ctab, syn, path, spaces, data, ext_stamps stamps id);
   407   in
   408     (case self of
   409       SgRef (Some r) => r := sign
   410     | _ => sys_error "Sign.create_sign");
   411     sign
   412   end;
   413 
   414 fun extend_sign keep extfun name decls
   415     (sg as Sg ({id = _, stamps}, {self, tsig, const_tab, syn, path, spaces, data})) =
   416   let
   417     val _ = check_stale sg;
   418     val (self', data') =
   419       if is_draft sg andalso keep then (self, data)
   420       else (SgRef (Some (ref sg)), prep_ext_data data);
   421   in
   422     create_sign self' stamps name
   423       (extfun (syn, tsig, const_tab, (path, spaces), data') decls)
   424   end;
   425 
   426 
   427 
   428 (** name spaces **)
   429 
   430 (* kinds *)
   431 
   432 val classK = "class";
   433 val typeK = "type";
   434 val constK = "const";
   435 
   436 
   437 (* declare and retrieve names *)
   438 
   439 fun space_of spaces kind =
   440   if_none (assoc (spaces, kind)) NameSpace.empty;
   441 
   442 (*input and output of qualified names*)
   443 fun intrn spaces kind = NameSpace.intern (space_of spaces kind);
   444 fun extrn spaces kind = NameSpace.extern (space_of spaces kind);
   445 fun cond_extrn spaces kind = NameSpace.cond_extern (space_of spaces kind);
   446 fun cond_extrn_table spaces kind tab = NameSpace.cond_extern_table (space_of spaces kind) tab;
   447 
   448 (*add / hide names*)
   449 fun change_space f spaces kind x = overwrite (spaces, (kind, f (space_of spaces kind, x)));
   450 fun add_names x = change_space NameSpace.extend x;
   451 fun hide_names x = change_space NameSpace.hide x;
   452 
   453 (*make full names*)
   454 fun full _ "" = error "Attempt to declare empty name \"\""
   455   | full None name = name
   456   | full (Some path) name =
   457       if NameSpace.is_qualified name then
   458         error ("Attempt to declare qualified name " ^ quote name)
   459       else NameSpace.pack (path @ [name]);
   460 
   461 (*base name*)
   462 val base_name = NameSpace.base;
   463 
   464 
   465 (* intern / extern names *)
   466 
   467 local
   468   (*prepare mapping of names*)
   469   fun mapping f add_xs t =
   470     let
   471       fun f' x = let val y = f x in if x = y then None else Some (x, y) end;
   472       val table = mapfilter f' (add_xs (t, []));
   473       fun lookup x = if_none (assoc (table, x)) x;
   474     in lookup end;
   475 
   476   (*intern / extern typ*)
   477   fun trn_typ trn T =
   478     T |> map_typ
   479       (mapping (trn classK) add_typ_classes T)
   480       (mapping (trn typeK) add_typ_tycons T);
   481 
   482   (*intern / extern term*)
   483   fun trn_term trn t =
   484     t |> map_term
   485       (mapping (trn classK) add_term_classes t)
   486       (mapping (trn typeK) add_term_tycons t)
   487       (mapping (trn constK) add_term_consts t);
   488 
   489   val spaces_of = #spaces o rep_sg;
   490 in
   491   fun intrn_class spaces = intrn spaces classK;
   492   fun extrn_class spaces = extrn spaces classK;
   493 
   494   val intrn_sort = map o intrn_class;
   495   val intrn_typ = trn_typ o intrn;
   496   val intrn_term = trn_term o intrn;
   497 
   498   val extrn_sort = map o extrn_class;
   499   val extrn_typ = trn_typ o extrn;
   500   val extrn_term = trn_term o extrn;
   501 
   502   fun intrn_tycons spaces T =
   503     map_typ I (mapping (intrn spaces typeK) add_typ_tycons T) T;
   504 
   505   val intern = intrn o spaces_of;
   506   val extern = extrn o spaces_of;
   507   val cond_extern = cond_extrn o spaces_of;
   508   fun cond_extern_table sg = cond_extrn_table (spaces_of sg);
   509 
   510   val intern_class = intrn_class o spaces_of;
   511   val intern_sort = intrn_sort o spaces_of;
   512   val intern_typ = intrn_typ o spaces_of;
   513   val intern_term = intrn_term o spaces_of;
   514 
   515   fun intern_tycon sg = intrn (spaces_of sg) typeK;
   516   fun intern_const sg = intrn (spaces_of sg) constK;
   517 
   518   val intern_tycons = intrn_tycons o spaces_of;
   519 
   520   val full_name = full o #path o rep_sg;
   521 
   522   fun full_name_path sg elems =
   523     full (Some (if_none (#path (rep_sg sg)) [] @ NameSpace.unpack elems));
   524 
   525 end;
   526 
   527 
   528 
   529 (** pretty printing of terms, types etc. **)
   530 
   531 fun pretty_term' syn (sg as Sg ({stamps, ...}, {spaces, ...})) t =
   532   Syntax.pretty_term syn
   533     (exists (equal "CPure" o !) stamps)
   534     (if ! NameSpace.long_names then t else extrn_term spaces t);
   535 
   536 fun pretty_term sg = pretty_term' (syn_of sg) sg;
   537 
   538 fun pretty_typ (Sg (_, {syn, spaces, ...})) T =
   539   Syntax.pretty_typ syn
   540     (if ! NameSpace.long_names then T else extrn_typ spaces T);
   541 
   542 fun pretty_sort (Sg (_, {syn, spaces, ...})) S =
   543   Syntax.pretty_sort syn
   544     (if ! NameSpace.long_names then S else extrn_sort spaces S);
   545 
   546 fun pretty_classrel sg (c1, c2) = Pretty.block
   547   [pretty_sort sg [c1], Pretty.str " <", Pretty.brk 1, pretty_sort sg [c2]];
   548 
   549 fun pretty_arity sg (t, Ss, S) =
   550   let
   551     val t' = cond_extern sg typeK t;
   552     val dom =
   553       if null Ss then []
   554       else [Pretty.list "(" ")" (map (pretty_sort sg) Ss), Pretty.brk 1];
   555   in
   556     Pretty.block
   557       ([Pretty.str (t' ^ " ::"), Pretty.brk 1] @ dom @ [pretty_sort sg S])
   558   end;
   559 
   560 fun string_of_term sg t = Pretty.string_of (pretty_term sg t);
   561 fun string_of_typ sg T = Pretty.string_of (pretty_typ sg T);
   562 fun string_of_sort sg S = Pretty.string_of (pretty_sort sg S);
   563 
   564 fun str_of_sort sg S = Pretty.str_of (pretty_sort sg S);
   565 fun str_of_classrel sg c1_c2 = Pretty.str_of (pretty_classrel sg c1_c2);
   566 fun str_of_arity sg ar = Pretty.str_of (pretty_arity sg ar);
   567 
   568 fun pprint_term sg = Pretty.pprint o Pretty.quote o (pretty_term sg);
   569 fun pprint_typ sg = Pretty.pprint o Pretty.quote o (pretty_typ sg);
   570 
   571 
   572 
   573 (** read sorts **)  (*exception ERROR*)
   574 
   575 fun err_in_sort s =
   576   error ("The error(s) above occurred in sort " ^ quote s);
   577 
   578 fun rd_sort syn tsig spaces str =
   579   let val S = intrn_sort spaces (Syntax.read_sort syn str handle ERROR => err_in_sort str)
   580   in Type.cert_sort tsig S handle TYPE (msg, _, _) => (error_msg msg; err_in_sort str) end;
   581 
   582 (*read and certify sort wrt a signature*)
   583 fun read_sort (sg as Sg (_, {tsig, syn, spaces, ...})) str =
   584   (check_stale sg; rd_sort syn tsig spaces str);
   585 
   586 fun cert_sort _ tsig _ = Type.cert_sort tsig;
   587 
   588 
   589 
   590 (** read types **)  (*exception ERROR*)
   591 
   592 fun err_in_type s =
   593   error ("The error(s) above occurred in type " ^ quote s);
   594 
   595 fun rd_raw_typ syn tsig spaces def_sort str =
   596   intrn_tycons spaces
   597     (Syntax.read_typ syn (Type.get_sort tsig def_sort (intrn_sort spaces)) str
   598       handle ERROR => err_in_type str);
   599 
   600 fun read_raw_typ' syn (sg as Sg (_, {tsig, spaces, ...}), def_sort) str =
   601   (check_stale sg; rd_raw_typ syn tsig spaces def_sort str);
   602 
   603 fun read_raw_typ (sg, def_sort) = read_raw_typ' (syn_of sg) (sg, def_sort);
   604 
   605 (*read and certify typ wrt a signature*)
   606 local
   607   fun read_typ_aux rd cert (sg, def_sort) str =
   608     (cert (tsig_of sg) (rd (sg, def_sort) str)
   609       handle TYPE (msg, _, _) => (error_msg msg; err_in_type str));
   610 in
   611   val read_typ              = read_typ_aux read_raw_typ Type.cert_typ;
   612   val read_typ_no_norm      = read_typ_aux read_raw_typ Type.cert_typ_no_norm;
   613   fun read_typ' syn         = read_typ_aux (read_raw_typ' syn) Type.cert_typ;
   614   fun read_typ_no_norm' syn = read_typ_aux (read_raw_typ' syn) Type.cert_typ_no_norm;
   615 end;
   616 
   617 
   618 
   619 (** certify classes, sorts, types and terms **)   (*exception TYPE*)
   620 
   621 val certify_class = Type.cert_class o tsig_of;
   622 val certify_sort = Type.cert_sort o tsig_of;
   623 val certify_typ = Type.cert_typ o tsig_of;
   624 val certify_typ_no_norm = Type.cert_typ_no_norm o tsig_of;
   625 
   626 fun certify_tycon sg c =
   627   if is_some (Symtab.lookup (#tycons (Type.rep_tsig (tsig_of sg)), c)) then c
   628   else raise TYPE ("Undeclared type constructor " ^ quote c, [], []);
   629 
   630 fun certify_tyabbr sg c =
   631   if is_some (Symtab.lookup (#abbrs (Type.rep_tsig (tsig_of sg)), c)) then c
   632   else raise TYPE ("Unknown type abbreviation " ^ quote c, [], []);
   633 
   634 fun certify_tyname sg c =
   635   certify_tycon sg c handle TYPE _ => certify_tyabbr sg c handle TYPE _ =>
   636     raise TYPE ("Unknown type name " ^ quote c, [], []);
   637 
   638 fun certify_const sg c =
   639   if is_some (const_type sg c) then c else raise TYPE ("Undeclared constant " ^ quote c, [], []);
   640 
   641 
   642 (* certify_term *)
   643 
   644 (*check for duplicate occurrences of TFree/TVar with distinct sorts*)
   645 fun nodup_tvars (env, Type (_, Ts)) = nodup_tvars_list (env, Ts)
   646   | nodup_tvars (env as (tfrees, tvars), T as TFree (v as (a, S))) =
   647       (case assoc_string (tfrees, a) of
   648         Some S' =>
   649           if S = S' then env
   650           else raise TYPE ("Type variable " ^ quote a ^
   651             " has two distinct sorts", [TFree (a, S'), T], [])
   652       | None => (v :: tfrees, tvars))
   653   | nodup_tvars (env as (tfrees, tvars), T as TVar (v as (a, S))) =
   654       (case assoc_string_int (tvars, a) of
   655         Some S' =>
   656           if S = S' then env
   657           else raise TYPE ("Type variable " ^ quote (Syntax.string_of_vname a) ^
   658             " has two distinct sorts", [TVar (a, S'), T], [])
   659       | None => (tfrees, v :: tvars))
   660 (*equivalent to foldl nodup_tvars_list, but 3X faster under Poly/ML*)
   661 and nodup_tvars_list (env, []) = env
   662   | nodup_tvars_list (env, T :: Ts) = nodup_tvars_list (nodup_tvars (env, T), Ts);
   663 
   664 (*check for duplicate occurrences of Free/Var with distinct types*)
   665 fun nodup_vars tm =
   666   let
   667     fun nodups (envs as (env as (frees, vars), envT)) tm =
   668       (case tm of
   669         Const (c, T) => (env, nodup_tvars (envT, T))
   670       | Free (v as (a, T)) =>
   671           (case assoc_string (frees, a) of
   672             Some T' =>
   673               if T = T' then (env, nodup_tvars (envT, T))
   674               else raise TYPE ("Variable " ^ quote a ^
   675                 " has two distinct types", [T', T], [])
   676           | None => ((v :: frees, vars), nodup_tvars (envT, T)))
   677       | Var (v as (ixn, T)) =>
   678           (case assoc_string_int (vars, ixn) of
   679             Some T' =>
   680               if T = T' then (env, nodup_tvars (envT, T))
   681               else raise TYPE ("Variable " ^ quote (Syntax.string_of_vname ixn) ^
   682                 " has two distinct types", [T', T], [])
   683           | None => ((frees, v :: vars), nodup_tvars (envT, T)))
   684       | Bound _ => envs
   685       | Abs (_, T, t) => nodups (env, nodup_tvars (envT, T)) t
   686       | s $ t => nodups (nodups envs s) t)
   687   in nodups (([], []), ([], [])) tm; tm end;
   688 
   689 (*compute and check type of the term*)
   690 fun type_check sg tm =
   691   let
   692     val prt = setmp Syntax.show_brackets true (pretty_term sg);
   693     val prT = pretty_typ sg;
   694 
   695     fun err_appl why bs t T u U =
   696       let
   697         val xs = map Free bs;           (*we do not rename here*)
   698         val t' = subst_bounds (xs, t);
   699         val u' = subst_bounds (xs, u);
   700         val text = cat_lines (TypeInfer.appl_error prt prT why t' T u' U);
   701       in raise TYPE (text, [T, U], [t', u']) end;
   702 
   703     fun typ_of (_, Const (_, T)) = T
   704       | typ_of (_, Free  (_, T)) = T
   705       | typ_of (_, Var (_, T)) = T
   706       | typ_of (bs, Bound i) = snd (nth_elem (i, bs) handle LIST _ =>
   707           raise TYPE ("Loose bound variable: B." ^ string_of_int i, [], [Bound i]))
   708       | typ_of (bs, Abs (x, T, body)) = T --> typ_of ((x, T) :: bs, body)
   709       | typ_of (bs, t $ u) =
   710           let val T = typ_of (bs, t) and U = typ_of (bs, u) in
   711             (case T of
   712               Type ("fun", [T1, T2]) =>
   713                 if T1 = U then T2 else err_appl "Incompatible operand type." bs t T u U
   714             | _ => err_appl "Operator not of function type." bs t T u U)
   715           end;
   716 
   717   in typ_of ([], tm) end;
   718 
   719 
   720 fun certify_term sg tm =
   721   let
   722     val _ = check_stale sg;
   723     val tsig = tsig_of sg;
   724 
   725     fun show_const a T = quote a ^ " :: " ^ quote (string_of_typ sg T);
   726 
   727     fun atom_err (errs, Const (a, T)) =
   728         (case const_type sg a of
   729           None => ("Undeclared constant " ^ show_const a T) :: errs
   730         | Some U =>
   731             if typ_instance sg (T, U) then errs
   732             else ("Illegal type for constant " ^ show_const a T) :: errs)
   733       | atom_err (errs, Var ((x, i), _)) =
   734           if i < 0 then ("Negative index for Var " ^ quote x) :: errs else errs
   735       | atom_err (errs, _) = errs;
   736 
   737     val norm_tm =
   738       (case it_term_types (Type.typ_errors tsig) (tm, []) of
   739         [] => Type.norm_term tsig tm
   740       | errs => raise TYPE (cat_lines errs, [], [tm]));
   741     val _ = nodup_vars norm_tm;
   742   in
   743     (case foldl_aterms atom_err ([], norm_tm) of
   744       [] => (norm_tm, type_check sg norm_tm, maxidx_of_term norm_tm)
   745     | errs => raise TYPE (cat_lines errs, [], [norm_tm]))
   746   end;
   747 
   748 
   749 (** infer_types **)         (*exception ERROR*)
   750 
   751 (*
   752   def_type: partial map from indexnames to types (constrains Frees, Vars)
   753   def_sort: partial map from indexnames to sorts (constrains TFrees, TVars)
   754   used: list of already used type variables
   755   freeze: if true then generated parameters are turned into TFrees, else TVars
   756 
   757   termss: lists of alternative parses (only one combination should be type-correct)
   758   typs: expected types
   759 *)
   760 
   761 fun infer_types_simult sg def_type def_sort used freeze args =
   762   let
   763     val tsig = tsig_of sg;
   764     val prt = setmp Syntax.show_brackets true (pretty_term sg);
   765     val prT = pretty_typ sg;
   766 
   767     val termss = foldr multiply (map fst args, [[]]);
   768     val typs =
   769       map (fn (_, T) => certify_typ sg T handle TYPE (msg, _, _) => error msg) args;
   770 
   771     fun infer ts = OK
   772       (Type.infer_types prt prT tsig (const_type sg) def_type def_sort
   773         (intern_const sg) (intern_tycons sg) (intern_sort sg) used freeze typs ts)
   774       handle TYPE (msg, _, _) => Error msg;
   775 
   776     val err_results = map infer termss;
   777     val errs = mapfilter get_error err_results;
   778     val results = mapfilter get_ok err_results;
   779 
   780     val ambiguity = length termss;      (* FIXME !? *)
   781     (* FIXME to syntax.ML!? *)
   782     fun ambig_msg () =
   783       if ambiguity > 1 andalso ambiguity <= ! Syntax.ambiguity_level
   784       then
   785         error_msg "Got more than one parse tree.\n\
   786           \Retry with smaller Syntax.ambiguity_level for more information."
   787       else ();
   788   in
   789     if null results then (ambig_msg (); error (cat_lines errs))
   790     else if length results = 1 then
   791       (if ambiguity > ! Syntax.ambiguity_level then
   792         warning "Fortunately, only one parse tree is type correct.\n\
   793           \You may still want to disambiguate your grammar or your input."
   794       else (); hd results)
   795     else (ambig_msg (); error ("More than one term is type correct:\n" ^
   796       (cat_lines (map (Pretty.string_of o prt) (flat (map fst results))))))
   797   end;
   798 
   799 
   800 fun infer_types sg def_type def_sort used freeze tsT =
   801   apfst hd (infer_types_simult sg def_type def_sort used freeze [tsT]);
   802 
   803 
   804 (** read_def_terms **)
   805 
   806 (*read terms, infer types*)
   807 fun read_def_terms' syn (sign, types, sorts) used freeze sTs =
   808   let
   809     fun read (s, T) =
   810       let val T' = certify_typ sign T handle TYPE (msg, _, _) => error msg
   811       in (Syntax.read syn T' s, T') end;
   812     val tsTs = map read sTs;
   813   in infer_types_simult sign types sorts used freeze tsTs end;
   814 
   815 fun read_def_terms (sign, types, sorts) = read_def_terms' (syn_of sign) (sign, types, sorts);
   816 
   817 fun simple_read_term sign T s =
   818   (read_def_terms (sign, K None, K None) [] true [(s, T)]
   819     handle ERROR => error ("The error(s) above occurred for " ^ s)) |> #1 |> hd;
   820 
   821 
   822 
   823 (** extend signature **)    (*exception ERROR*)
   824 
   825 (** signature extension functions **)  (*exception ERROR*)
   826 
   827 fun decls_of path name_of mfixs =
   828   map (fn (x, y, mx) => (full path (name_of x mx), y)) mfixs;
   829 
   830 fun no_read _ _ _ decl = decl;
   831 
   832 
   833 (* add default sort *)
   834 
   835 fun ext_defS prep_sort (syn, tsig, ctab, (path, spaces), data) S =
   836   (syn, Type.ext_tsig_defsort tsig (prep_sort syn tsig spaces S), ctab, (path, spaces), data);
   837 
   838 fun ext_defsort arg   = ext_defS rd_sort arg;
   839 fun ext_defsort_i arg = ext_defS cert_sort arg;
   840 
   841 
   842 (* add type constructors *)
   843 
   844 fun ext_types (syn, tsig, ctab, (path, spaces), data) types =
   845   let val decls = decls_of path Syntax.type_name types in
   846     (Syntax.extend_type_gram types syn,
   847       Type.ext_tsig_types tsig decls, ctab,
   848       (path, add_names spaces typeK (map fst decls)), data)
   849   end;
   850 
   851 fun ext_nonterminals sg nonterms =
   852   ext_types sg (map (fn n => (n, 0, Syntax.NoSyn)) nonterms);
   853 
   854 
   855 (* add type abbreviations *)
   856 
   857 fun read_abbr syn tsig spaces (t, vs, rhs_src) =
   858   (t, vs, rd_raw_typ syn tsig spaces (K None) rhs_src)
   859     handle ERROR => error ("in type abbreviation " ^ t);
   860 
   861 fun ext_abbrs rd_abbr (syn, tsig, ctab, (path, spaces), data) abbrs =
   862   let
   863     fun mfix_of (t, vs, _, mx) = (t, length vs, mx);
   864     val syn' = Syntax.extend_type_gram (map mfix_of abbrs) syn;
   865 
   866     val abbrs' =
   867       map (fn (t, vs, rhs, mx) =>
   868         (full path (Syntax.type_name t mx), vs, rhs)) abbrs;
   869     val spaces' = add_names spaces typeK (map #1 abbrs');
   870     val decls = map (rd_abbr syn' tsig spaces') abbrs';
   871   in
   872     (syn', Type.ext_tsig_abbrs tsig decls, ctab, (path, spaces'), data)
   873   end;
   874 
   875 fun ext_tyabbrs abbrs = ext_abbrs read_abbr abbrs;
   876 fun ext_tyabbrs_i abbrs = ext_abbrs no_read abbrs;
   877 
   878 
   879 (* add type arities *)
   880 
   881 fun ext_ars int prep_sort (syn, tsig, ctab, (path, spaces), data) arities =
   882   let
   883     val prepS = prep_sort syn tsig spaces;
   884     fun prep_arity (c, Ss, S) =
   885       (if int then intrn spaces typeK c else c, map prepS Ss, prepS S);
   886     val tsig' = Type.ext_tsig_arities tsig (map prep_arity arities);
   887     val log_types = Type.logical_types tsig';
   888   in
   889     (Syntax.extend_log_types log_types syn, tsig', ctab, (path, spaces), data)
   890   end;
   891 
   892 fun ext_arities arg   = ext_ars true rd_sort arg;
   893 fun ext_arities_i arg = ext_ars false cert_sort arg;
   894 
   895 
   896 (* add term constants and syntax *)
   897 
   898 fun const_name path c mx =
   899   full path (Syntax.const_name c mx);
   900 
   901 fun err_in_const c =
   902   error ("in declaration of constant " ^ quote c);
   903 
   904 fun err_dup_consts cs =
   905   error ("Duplicate declaration of constant(s) " ^ commas_quote cs);
   906 
   907 
   908 fun read_const syn tsig (path, spaces) (c, ty_src, mx) =
   909   (c, rd_raw_typ syn tsig spaces (K None) ty_src, mx)
   910     handle ERROR => err_in_const (const_name path c mx);
   911 
   912 fun ext_cnsts rd_const syn_only prmode (syn, tsig, ctab, (path, spaces), data) raw_consts =
   913   let
   914     fun prep_const (c, ty, mx) =
   915       (c, compress_type (Type.varifyT (Type.cert_typ tsig (Type.no_tvars ty))), mx)
   916         handle TYPE (msg, _, _) =>
   917           (error_msg msg; err_in_const (const_name path c mx));
   918 
   919     val consts = map (prep_const o rd_const syn tsig (path, spaces)) raw_consts;
   920     val decls =
   921       if syn_only then []
   922       else decls_of path Syntax.const_name consts;
   923   in
   924     (Syntax.extend_const_gram prmode consts syn, tsig,
   925       Symtab.extend (ctab, decls)
   926         handle Symtab.DUPS cs => err_dup_consts cs,
   927       (path, add_names spaces constK (map fst decls)), data)
   928   end;
   929 
   930 fun ext_consts_i sg = ext_cnsts no_read false ("", true) sg;
   931 fun ext_consts sg = ext_cnsts read_const false ("", true) sg;
   932 fun ext_syntax_i sg = ext_cnsts no_read true ("", true) sg;
   933 fun ext_syntax sg = ext_cnsts read_const true ("", true) sg;
   934 fun ext_modesyntax_i sg (prmode, consts) = ext_cnsts no_read true prmode sg consts;
   935 fun ext_modesyntax sg (prmode, consts) = ext_cnsts read_const true prmode sg consts;
   936 
   937 
   938 (* add type classes *)
   939 
   940 fun const_of_class c = c ^ "_class";
   941 
   942 fun class_of_const c_class =
   943   let
   944     val c = implode (take (size c_class - size "_class", explode c_class));
   945   in
   946     if const_of_class c = c_class then c
   947     else raise TERM ("class_of_const: bad name " ^ quote c_class, [])
   948   end;
   949 
   950 
   951 fun ext_classes int (syn, tsig, ctab, (path, spaces), data) classes =
   952   let
   953     val names = map fst classes;
   954     val consts =
   955       map (fn c => (const_of_class c, a_itselfT --> propT, NoSyn)) names;
   956 
   957     val full_names = map (full path) names;
   958     val spaces' = add_names spaces classK full_names;
   959     val intrn = if int then map (intrn_class spaces') else I;
   960     val classes' =
   961       ListPair.map (fn (c, (_, cs)) => (c, intrn cs)) (full_names, classes);
   962   in
   963     ext_consts_i
   964       (Syntax.extend_consts names syn,
   965         Type.ext_tsig_classes tsig classes', ctab, (path, spaces'), data)
   966     consts
   967   end;
   968 
   969 
   970 (* add to classrel *)
   971 
   972 fun ext_classrel int (syn, tsig, ctab, (path, spaces), data) pairs =
   973   let val intrn = if int then map (pairself (intrn_class spaces)) else I in
   974     (syn, Type.ext_tsig_classrel tsig (intrn pairs), ctab, (path, spaces), data)
   975   end;
   976 
   977 
   978 (* add translation rules *)
   979 
   980 fun ext_trrules (syn, tsig, ctab, (path, spaces), data) args =
   981   (syn |> Syntax.extend_trrules
   982     (map (Syntax.map_trrule (fn (root, str) => (intrn spaces typeK root, str))) args),
   983       tsig, ctab, (path, spaces), data);
   984 
   985 
   986 (* add to syntax *)
   987 
   988 fun ext_syn extfun (syn, tsig, ctab, names, data) args =
   989   (extfun args syn, tsig, ctab, names, data);
   990 
   991 
   992 (* add to path *)
   993 
   994 fun ext_path (syn, tsig, ctab, (path, spaces), data) elems =
   995   let
   996     val path' =
   997       if elems = "//" then None
   998       else if elems = "/" then Some []
   999       else if elems = ".." andalso is_some path andalso path <> Some [] then
  1000         Some (fst (split_last (the path)))
  1001       else Some (if_none path [] @ NameSpace.unpack elems);
  1002   in
  1003     (syn, tsig, ctab, (path', spaces), data)
  1004   end;
  1005 
  1006 
  1007 (* change name space *)
  1008 
  1009 fun ext_add_space (syn, tsig, ctab, (path, spaces), data) (kind, names) =
  1010   (syn, tsig, ctab, (path, add_names spaces kind names), data);
  1011 
  1012 fun ext_hide_space (syn, tsig, ctab, (path, spaces), data) (kind, xnames) =
  1013   (syn, tsig, ctab, (path, hide_names spaces kind (map (intrn spaces kind) xnames)), data);
  1014 
  1015 fun ext_hide_space_i (syn, tsig, ctab, (path, spaces), data) (kind, names) =
  1016   (syn, tsig, ctab, (path, hide_names spaces kind names), data);
  1017 
  1018 
  1019 (* signature data *)
  1020 
  1021 fun ext_init_data sg (syn, tsig, ctab, names, data) (kind, (e, cp, fin, ext, mrg, prt)) =
  1022   (syn, tsig, ctab, names, init_data_sg sg data kind e cp fin ext mrg prt);
  1023 
  1024 fun ext_put_data sg (syn, tsig, ctab, names, data) (kind, f, x) =
  1025   (syn, tsig, ctab, names, put_data_sg sg data kind f x);
  1026 
  1027 
  1028 fun finish_data (k, (e, mths as (_, fin, _, _, _))) =
  1029   (k, (fin e handle exn => err_method "finish" (Object.name_of_kind k) exn, mths));
  1030 
  1031 fun ext_finish_data (syn, tsig, ctab, names, Data tab) () =
  1032   (syn, tsig, ctab, names, Data (Symtab.map finish_data tab));
  1033 
  1034 
  1035 fun copy_data (k, (e, mths as (cp, _, _, _, _))) =
  1036   (k, (cp e handle exn => err_method "copy" (Object.name_of_kind k) exn, mths));
  1037 
  1038 fun copy (sg as Sg ({id = _, stamps}, {self, tsig, const_tab, syn, path, spaces, data})) =
  1039   let
  1040     val _ = check_stale sg;
  1041     val self' = SgRef (Some (ref sg));
  1042     val Data tab = data;
  1043     val data' = Data (Symtab.map copy_data tab);
  1044   in create_sign self' stamps "#" (syn, tsig, const_tab, (path, spaces), data') end;
  1045 
  1046 
  1047 (* the external interfaces *)
  1048 
  1049 val add_classes       = extend_sign true (ext_classes true) "#";
  1050 val add_classes_i     = extend_sign true (ext_classes false) "#";
  1051 val add_classrel      = extend_sign true (ext_classrel true) "#";
  1052 val add_classrel_i    = extend_sign true (ext_classrel false) "#";
  1053 val add_defsort       = extend_sign true ext_defsort "#";
  1054 val add_defsort_i     = extend_sign true ext_defsort_i "#";
  1055 val add_types         = extend_sign true ext_types "#";
  1056 val add_nonterminals  = extend_sign true ext_nonterminals "#";
  1057 val add_tyabbrs       = extend_sign true ext_tyabbrs "#";
  1058 val add_tyabbrs_i     = extend_sign true ext_tyabbrs_i "#";
  1059 val add_arities       = extend_sign true ext_arities "#";
  1060 val add_arities_i     = extend_sign true ext_arities_i "#";
  1061 val add_consts        = extend_sign true ext_consts "#";
  1062 val add_consts_i      = extend_sign true ext_consts_i "#";
  1063 val add_syntax        = extend_sign true ext_syntax "#";
  1064 val add_syntax_i      = extend_sign true ext_syntax_i "#";
  1065 val add_modesyntax    = extend_sign true ext_modesyntax "#";
  1066 val add_modesyntax_i  = extend_sign true ext_modesyntax_i "#";
  1067 val add_trfuns        = extend_sign true (ext_syn Syntax.extend_trfuns) "#";
  1068 val add_trfunsT       = extend_sign true (ext_syn Syntax.extend_trfunsT) "#";
  1069 val add_tokentrfuns   = extend_sign true (ext_syn Syntax.extend_tokentrfuns) "#";
  1070 val add_trrules       = extend_sign true ext_trrules "#";
  1071 val add_trrules_i     = extend_sign true (ext_syn Syntax.extend_trrules_i) "#";
  1072 val add_path          = extend_sign true ext_path "#";
  1073 val add_space         = extend_sign true ext_add_space "#";
  1074 val hide_space        = extend_sign true ext_hide_space "#";
  1075 val hide_space_i      = extend_sign true ext_hide_space_i "#";
  1076 fun init_data arg sg  = extend_sign true (ext_init_data sg) "#" arg sg;
  1077 fun put_data k f x sg = extend_sign true (ext_put_data sg) "#" (k, f, x) sg;
  1078 fun finish sg         = extend_sign true ext_finish_data "#" () sg;
  1079 fun add_name name sg  = extend_sign true K name () sg;
  1080 fun prep_ext sg       = extend_sign false K "#" () sg;
  1081 
  1082 
  1083 
  1084 (** merge signatures **)        (*exception TERM*)
  1085 
  1086 (* merge_stamps *)
  1087 
  1088 fun merge_stamps stamps1 stamps2 =
  1089   let val stamps = merge_rev_lists stamps1 stamps2 in
  1090     (case duplicates (map ! stamps) of
  1091       [] => stamps
  1092     | dups => raise TERM ("Attempt to merge different versions of theories "
  1093         ^ commas_quote dups, []))
  1094   end;
  1095 
  1096 
  1097 (* implicit merge -- trivial only *)
  1098 
  1099 fun merge_refs (sgr1 as SgRef (Some (ref (sg1 as Sg ({stamps = s1, ...}, _)))),
  1100         sgr2 as SgRef (Some (ref (sg2 as Sg ({stamps = s2, ...}, _))))) =
  1101       if fast_subsig (sg2, sg1) then sgr1
  1102       else if fast_subsig (sg1, sg2) then sgr2
  1103       else if subsig (sg2, sg1) then sgr1
  1104       else if subsig (sg1, sg2) then sgr2
  1105       else (merge_stamps s1 s2; (*check for different versions*)
  1106         raise TERM ("Attempt to do non-trivial merge of signatures", []))
  1107   | merge_refs _ = sys_error "Sign.merge_refs";
  1108 
  1109 val merge = deref o merge_refs o pairself self_ref;
  1110 
  1111 
  1112 (* proper merge *)              (*exception TERM/ERROR*)
  1113 
  1114 val PureN = "Pure";
  1115 val CPureN = "CPure";
  1116 
  1117 fun nontriv_merge (sg1, sg2) =
  1118   if subsig (sg2, sg1) then sg1
  1119   else if subsig (sg1, sg2) then sg2
  1120   else if is_draft sg1 orelse is_draft sg2 then
  1121     raise TERM ("Attempt to merge draft signatures", [])
  1122   else if exists_stamp PureN sg1 andalso exists_stamp CPureN sg2 orelse
  1123       exists_stamp CPureN sg1 andalso exists_stamp PureN sg2 then
  1124     raise TERM ("Cannot merge Pure and CPure signatures", [])
  1125   else
  1126     (*neither is union already; must form union*)
  1127     let
  1128       val Sg ({id = _, stamps = stamps1}, {self = _, tsig = tsig1, const_tab = const_tab1,
  1129         syn = syn1, path = _, spaces = spaces1, data = data1}) = sg1;
  1130       val Sg ({id = _, stamps = stamps2}, {self = _, tsig = tsig2, const_tab = const_tab2,
  1131         syn = syn2, path = _, spaces = spaces2, data = data2}) = sg2;
  1132 
  1133       val id = ref "";
  1134       val self_ref = ref sg1;                   (*dummy value*)
  1135       val self = SgRef (Some self_ref);
  1136 
  1137       val stamps = merge_stamps stamps1 stamps2;
  1138       val tsig = Type.merge_tsigs (tsig1, tsig2);
  1139       val const_tab = Symtab.merge (op =) (const_tab1, const_tab2)
  1140         handle Symtab.DUPS cs =>
  1141           raise TERM ("Incompatible types for constant(s) " ^ commas_quote cs, []);
  1142       val syn = Syntax.merge_syntaxes syn1 syn2;
  1143 
  1144       val path = Some [];
  1145       val kinds = distinct (map fst (spaces1 @ spaces2));
  1146       val spaces =
  1147         kinds ~~
  1148           ListPair.map NameSpace.merge
  1149             (map (space_of spaces1) kinds, map (space_of spaces2) kinds);
  1150 
  1151       val data = merge_data (data1, data2);
  1152 
  1153       val sign = make_sign (id, self, tsig, const_tab, syn, path, spaces, data, stamps);
  1154     in
  1155       self_ref := sign; sign
  1156     end;
  1157 
  1158 
  1159 
  1160 (** partial Pure signature **)
  1161 
  1162 val dummy_sg = make_sign (ref "", SgRef None, Type.tsig0,
  1163   Symtab.empty, Syntax.pure_syn, Some [], [], empty_data, []);
  1164 
  1165 val pre_pure =
  1166   create_sign (SgRef (Some (ref dummy_sg))) [] "#"
  1167     (Syntax.pure_syn, Type.tsig0, Symtab.empty, (Some [], []), empty_data);
  1168 
  1169 
  1170 end;