src/Pure/sign.ML
author wenzelm
Thu Nov 20 12:50:57 1997 +0100 (1997-11-20)
changeset 4249 34b7aafdc1bc
parent 4228 22e3f0368c85
child 4256 e768c42069bb
permissions -rw-r--r--
exported pretty_classrel, pretty_arity;
added infer_types_simult;
tuned infer_types interface;
moved print_sg to display.ML;
     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   val rep_sg: sg ->
    23    {self: sg_ref,
    24     tsig: Type.type_sig,
    25     const_tab: typ Symtab.table,
    26     syn: Syntax.syntax,
    27     path: string list,
    28     spaces: (string * NameSpace.T) list,
    29     data: Data.T}
    30   val name_of: sg -> string
    31   val stamp_names_of: sg -> string list
    32   val tsig_of: sg -> Type.type_sig
    33   val deref: sg_ref -> sg
    34   val self_ref: sg -> sg_ref
    35   val subsig: sg * sg -> bool
    36   val eq_sg: sg * sg -> bool
    37   val same_sg: sg * sg -> bool
    38   val is_draft: sg -> bool
    39   val const_type: sg -> string -> typ option
    40   val classes: sg -> class list
    41   val subsort: sg -> sort * sort -> bool
    42   val nodup_Vars: term -> unit
    43   val norm_sort: sg -> sort -> sort
    44   val nonempty_sort: sg -> sort list -> sort -> bool
    45   val long_names: bool ref
    46   val classK: string
    47   val typeK: string
    48   val constK: string
    49   val full_name: sg -> bstring -> string
    50   val base_name: string -> bstring
    51   val intern: sg -> string -> xstring -> string
    52   val extern: sg -> string -> string -> xstring
    53   val cond_extern: sg -> string -> string -> xstring
    54   val intern_class: sg -> xclass -> class
    55   val intern_tycon: sg -> xstring -> string
    56   val intern_const: sg -> xstring -> string
    57   val intern_sort: sg -> xsort -> sort
    58   val intern_typ: sg -> xtyp -> typ
    59   val intern_term: sg -> xterm -> term
    60   val intern_tycons: sg -> xtyp -> typ
    61   val pretty_sg: sg -> Pretty.T
    62   val str_of_sg: sg -> string
    63   val pprint_sg: sg -> pprint_args -> unit
    64   val pretty_term: sg -> term -> Pretty.T
    65   val pretty_typ: sg -> typ -> Pretty.T
    66   val pretty_sort: sg -> sort -> Pretty.T
    67   val pretty_classrel: sg -> class * class -> Pretty.T
    68   val pretty_arity: sg -> string * sort list * sort -> Pretty.T
    69   val string_of_term: sg -> term -> string
    70   val string_of_typ: sg -> typ -> string
    71   val string_of_sort: sg -> sort -> string
    72   val str_of_sort: sg -> sort -> string
    73   val str_of_classrel: sg -> class * class -> string
    74   val str_of_arity: sg -> string * sort list * sort -> string
    75   val pprint_term: sg -> term -> pprint_args -> unit
    76   val pprint_typ: sg -> typ -> pprint_args -> unit
    77   val certify_typ: sg -> typ -> typ
    78   val certify_term: sg -> term -> term * typ * int
    79   val read_raw_typ: sg * (indexname -> sort option) -> string -> typ
    80   val read_typ: sg * (indexname -> sort option) -> string -> typ
    81   val infer_types: sg -> (indexname -> typ option) ->
    82     (indexname -> sort option) -> string list -> bool
    83     -> xterm list * typ -> term * (indexname * typ) list
    84   val infer_types_simult: sg -> (indexname -> typ option) ->
    85     (indexname -> sort option) -> string list -> bool
    86     -> (xterm list * typ) list -> term list * (indexname * typ) list
    87   val add_classes: (bclass * xclass list) list -> sg -> sg
    88   val add_classes_i: (bclass * class list) list -> sg -> sg
    89   val add_classrel: (xclass * xclass) list -> sg -> sg
    90   val add_classrel_i: (class * class) list -> sg -> sg
    91   val add_defsort: xsort -> sg -> sg
    92   val add_defsort_i: sort -> sg -> sg
    93   val add_types: (bstring * int * mixfix) list -> sg -> sg
    94   val add_tyabbrs: (bstring * string list * string * mixfix) list -> sg -> sg
    95   val add_tyabbrs_i: (bstring * string list * typ * mixfix) list -> sg -> sg
    96   val add_arities: (xstring * xsort list * xsort) list -> sg -> sg
    97   val add_arities_i: (string * sort list * sort) list -> sg -> sg
    98   val add_consts: (bstring * string * mixfix) list -> sg -> sg
    99   val add_consts_i: (bstring * typ * mixfix) list -> sg -> sg
   100   val add_syntax: (bstring * string * mixfix) list -> sg -> sg
   101   val add_syntax_i: (bstring * typ * mixfix) list -> sg -> sg
   102   val add_modesyntax: (string * bool) * (bstring * string * mixfix) list -> sg -> sg
   103   val add_modesyntax_i: (string * bool) * (bstring * typ * mixfix) list -> sg -> sg
   104   val add_trfuns:
   105     (bstring * (ast list -> ast)) list *
   106     (bstring * (term list -> term)) list *
   107     (bstring * (term list -> term)) list *
   108     (bstring * (ast list -> ast)) list -> sg -> sg
   109   val add_trfunsT:
   110     (bstring * (bool -> typ -> term list -> term)) list -> sg -> sg
   111   val add_tokentrfuns:
   112     (string * string * (string -> string * int)) list -> sg -> sg
   113   val add_trrules: (string * string) Syntax.trrule list -> sg -> sg
   114   val add_trrules_i: ast Syntax.trrule list -> sg -> sg
   115   val add_path: string -> sg -> sg
   116   val add_space: string * string list -> sg -> sg
   117   val add_name: string -> sg -> sg
   118   val init_data: string * (object * (object -> object) *
   119     (object * object -> object) * (object -> unit)) -> sg -> sg
   120   val get_data: sg -> string -> object
   121   val put_data: string * object -> sg -> sg
   122   val print_data: sg -> string -> unit
   123   val merge_refs: sg_ref * sg_ref -> sg_ref
   124   val prep_ext: sg -> sg
   125   val merge: sg * sg -> sg
   126   val pre_pure: sg
   127   val const_of_class: class -> string
   128   val class_of_const: string -> class
   129 end;
   130 
   131 structure Sign: SIGN =
   132 struct
   133 
   134 
   135 (** datatype sg **)
   136 
   137 datatype sg =
   138   Sg of
   139    {id: string ref,                             (*id*)
   140     stamps: string ref list} *                  (*unique theory indentifier*)
   141    {self: sg_ref,                               (*mutable self reference*)
   142     tsig: Type.type_sig,                        (*order-sorted signature of types*)
   143     const_tab: typ Symtab.table,                (*type schemes of constants*)
   144     syn: Syntax.syntax,                         (*syntax for parsing and printing*)
   145     path: string list,                          (*current name space entry prefix*)
   146     spaces: (string * NameSpace.T) list,        (*name spaces for consts, types etc.*)
   147     data: Data.T}                               (*additional data*)
   148 and sg_ref =
   149   SgRef of sg ref option;
   150 
   151 (*make signature*)
   152 fun make_sign (id, self, tsig, const_tab, syn, path, spaces, data, stamps) =
   153   Sg ({id = id, stamps = stamps}, {self = self, tsig = tsig, const_tab = const_tab,
   154     syn = syn, path = path, spaces = spaces, data = data});
   155 
   156 
   157 (* basic components *)
   158 
   159 fun rep_sg (Sg (_, args)) = args;
   160 
   161 (*show stamps*)
   162 fun stamp_names_of (Sg ({stamps, ...}, _)) = rev (map ! stamps);
   163 fun pretty_sg sg = Pretty.str_list "{" "}" (stamp_names_of sg);
   164 val str_of_sg = Pretty.str_of o pretty_sg;
   165 val pprint_sg = Pretty.pprint o pretty_sg;
   166 
   167 val tsig_of = #tsig o rep_sg;
   168 
   169 fun const_type (Sg (_, {const_tab, ...})) c = Symtab.lookup (const_tab, c);
   170 val classes = #classes o Type.rep_tsig o tsig_of;
   171 
   172 val subsort = Type.subsort o tsig_of;
   173 val norm_sort = Type.norm_sort o tsig_of;
   174 val nonempty_sort = Type.nonempty_sort o tsig_of;
   175 
   176 
   177 (* data *)
   178 
   179 fun access_data f sg k = f (#data (rep_sg sg)) k
   180   handle ERROR => error ("of theory " ^ str_of_sg sg);
   181 
   182 val get_data = access_data Data.get;
   183 val print_data = access_data Data.print;
   184 
   185 
   186 (* id and self *)
   187 
   188 fun check_stale (sg as Sg ({id, ...},
   189         {self = SgRef (Some (ref (Sg ({id = id', ...}, _)))), ...})) =
   190       if id = id' then sg
   191       else raise TERM ("Stale signature: " ^ str_of_sg sg, [])
   192   | check_stale _ = sys_error "Sign.check_stale";
   193 
   194 fun self_ref (sg as Sg (_, {self, ...})) = (check_stale sg; self);
   195 
   196 fun deref (SgRef (Some (ref sg))) = sg
   197   | deref (SgRef None) = sys_error "Sign.deref";
   198 
   199 fun name_of (sg as Sg ({id = ref name, ...}, _)) =
   200   if name = "" orelse name = "#" then
   201     raise TERM ("Nameless signature " ^ str_of_sg sg, [])
   202   else name;
   203 
   204 
   205 (* inclusion and equality *)
   206 
   207 local
   208   (*avoiding polymorphic equality: factor 10 speedup*)
   209   fun mem_stamp (_:string ref, []) = false
   210     | mem_stamp (x, y :: ys) = x = y orelse mem_stamp (x, ys);
   211 
   212   fun subset_stamp ([], ys) = true
   213     | subset_stamp (x :: xs, ys) =
   214         mem_stamp (x, ys) andalso subset_stamp (xs, ys);
   215 
   216   (*fast partial test*)
   217   fun fast_sub ([]: string ref list, _) = true
   218     | fast_sub (_, []) = false
   219     | fast_sub (x :: xs, y :: ys) =
   220         if x = y then fast_sub (xs, ys)
   221         else fast_sub (x :: xs, ys);
   222 in
   223   fun eq_sg (sg1 as Sg ({id = id1, ...}, _), sg2 as Sg ({id = id2, ...}, _)) =
   224     (check_stale sg1; check_stale sg2; id1 = id2);
   225 
   226   fun subsig (sg1 as Sg ({stamps = s1, ...}, _), sg2 as Sg ({stamps = s2, ...}, _)) =
   227     eq_sg (sg1, sg2) orelse subset_stamp (s1, s2);
   228 
   229   fun fast_subsig (sg1 as Sg ({stamps = s1, ...}, _), sg2 as Sg ({stamps = s2, ...}, _)) =
   230     eq_sg (sg1, sg2) orelse fast_sub (s1, s2);
   231 end;
   232 
   233 
   234 (*test if same theory names are contained in signatures' stamps,
   235   i.e. if signatures belong to same theory but not necessarily to the
   236   same version of it*)
   237 fun same_sg (sg1 as Sg ({stamps = s1, ...}, _), sg2 as Sg ({stamps = s2, ...}, _)) =
   238   eq_sg (sg1, sg2) orelse eq_set_string (pairself (map (op !)) (s1, s2));
   239 
   240 (*test for drafts*)
   241 fun is_draft (Sg ({stamps = ref "#" :: _, ...}, _)) = true
   242   | is_draft _ = false;
   243 
   244 
   245 (* build signature *)
   246 
   247 fun ext_stamps stamps (id as ref name) =
   248   let val stmps = (case stamps of ref "#" :: ss => ss | ss => ss) in
   249     if exists (equal name o !) stmps then
   250       error ("Theory already contains a " ^ quote name ^ " component")
   251     else id :: stmps
   252   end;
   253 
   254 fun create_sign self stamps name (syn, tsig, ctab, (path, spaces), data) =
   255   let
   256     val id = ref name;
   257     val sign =
   258       make_sign (id, self, tsig, ctab, syn, path, spaces, data, ext_stamps stamps id);
   259   in
   260     (case self of
   261       SgRef (Some r) => r := sign
   262     | _ => sys_error "Sign.create_sign");
   263     sign
   264   end;
   265 
   266 fun extend_sign keep extfun name decls
   267     (sg as Sg ({id = _, stamps}, {self, tsig, const_tab, syn, path, spaces, data})) =
   268   let
   269     val _ = check_stale sg;
   270     val (self', data') =
   271       if is_draft sg andalso keep then (self, data)
   272       else (SgRef (Some (ref sg)), Data.prep_ext data);
   273   in
   274     create_sign self' stamps name
   275       (extfun (syn, tsig, const_tab, (path, spaces), data') decls)
   276   end;
   277 
   278 
   279 
   280 (** name spaces **)
   281 
   282 (*prune names on output by default*)
   283 val long_names = ref false;
   284 
   285 
   286 (* kinds *)
   287 
   288 val classK = "class";
   289 val typeK = "type";
   290 val constK = "const";
   291 
   292 
   293 (* add and retrieve names *)
   294 
   295 fun space_of spaces kind =
   296   if_none (assoc (spaces, kind)) NameSpace.empty;
   297 
   298 (*input and output of qualified names*)
   299 fun intrn spaces kind = NameSpace.intern (space_of spaces kind);
   300 fun extrn spaces kind = NameSpace.extern (space_of spaces kind);
   301 
   302 (*add names*)
   303 fun add_names spaces kind names =
   304   let val space' = NameSpace.extend (names, space_of spaces kind) in
   305     overwrite (spaces, (kind, space'))
   306   end;
   307 
   308 (*make full names*)
   309 fun full path name =
   310   if NameSpace.qualified name then
   311     error ("Attempt to declare qualified name " ^ quote name)
   312   else NameSpace.pack (path @ [name]);
   313 
   314 (*base name*)
   315 val base_name = NameSpace.base;
   316 
   317 
   318 (* intern / extern names *)
   319 
   320 local
   321   (*prepare mapping of names*)
   322   fun mapping f add_xs t =
   323     let
   324       fun f' x = let val y = f x in if x = y then None else Some (x, y) end;
   325       val table = mapfilter f' (add_xs (t, []));
   326       fun lookup x = if_none (assoc (table, x)) x;
   327     in lookup end;
   328 
   329   (*intern / extern typ*)
   330   fun trn_typ trn T =
   331     T |> map_typ
   332       (mapping (trn classK) add_typ_classes T)
   333       (mapping (trn typeK) add_typ_tycons T);
   334 
   335   (*intern / extern term*)
   336   fun trn_term trn t =
   337     t |> map_term
   338       (mapping (trn classK) add_term_classes t)
   339       (mapping (trn typeK) add_term_tycons t)
   340       (mapping (trn constK) add_term_consts t);
   341 
   342   val spaces_of = #spaces o rep_sg;
   343 in
   344   fun intrn_class spaces = intrn spaces classK;
   345   fun extrn_class spaces = extrn spaces classK;
   346 
   347   val intrn_sort = map o intrn_class;
   348   val intrn_typ = trn_typ o intrn;
   349   val intrn_term = trn_term o intrn;
   350 
   351   val extrn_sort = map o extrn_class;
   352   val extrn_typ = trn_typ o extrn;
   353   val extrn_term = trn_term o extrn;
   354 
   355   fun intrn_tycons spaces T =
   356     map_typ I (mapping (intrn spaces typeK) add_typ_tycons T) T;
   357 
   358   val intern = intrn o spaces_of;
   359   val extern = extrn o spaces_of;
   360   fun cond_extern sg kind = if ! long_names then I else extern sg kind;
   361 
   362   val intern_class = intrn_class o spaces_of;
   363   val intern_sort = intrn_sort o spaces_of;
   364   val intern_typ = intrn_typ o spaces_of;
   365   val intern_term = intrn_term o spaces_of;
   366 
   367   fun intern_tycon sg = intrn (spaces_of sg) typeK;
   368   fun intern_const sg = intrn (spaces_of sg) constK;
   369 
   370   val intern_tycons = intrn_tycons o spaces_of;
   371 
   372   val full_name = full o #path o rep_sg;
   373 end;
   374 
   375 
   376 
   377 (** pretty printing of terms, types etc. **)
   378 
   379 fun pretty_term (sg as Sg ({stamps, ...}, {syn, spaces, ...})) t =
   380   Syntax.pretty_term syn
   381     (exists (equal "CPure" o !) stamps)
   382     (if ! long_names then t else extrn_term spaces t);
   383 
   384 fun pretty_typ (Sg (_, {syn, spaces, ...})) T =
   385   Syntax.pretty_typ syn
   386     (if ! long_names then T else extrn_typ spaces T);
   387 
   388 fun pretty_sort (Sg (_, {syn, spaces, ...})) S =
   389   Syntax.pretty_sort syn
   390     (if ! long_names then S else extrn_sort spaces S);
   391 
   392 fun pretty_classrel sg (c1, c2) = Pretty.block
   393   [pretty_sort sg [c1], Pretty.str " <", Pretty.brk 1, pretty_sort sg [c2]];
   394 
   395 fun pretty_arity sg (t, Ss, S) =
   396   let
   397     val t' = cond_extern sg typeK t;
   398     val dom =
   399       if null Ss then []
   400       else [Pretty.list "(" ")" (map (pretty_sort sg) Ss), Pretty.brk 1];
   401   in
   402     Pretty.block
   403       ([Pretty.str (t' ^ " ::"), Pretty.brk 1] @ dom @ [pretty_sort sg S])
   404   end;
   405 
   406 fun string_of_term sg t = Pretty.string_of (pretty_term sg t);
   407 fun string_of_typ sg T = Pretty.string_of (pretty_typ sg T);
   408 fun string_of_sort sg S = Pretty.string_of (pretty_sort sg S);
   409 
   410 fun str_of_sort sg S = Pretty.str_of (pretty_sort sg S);
   411 fun str_of_classrel sg c1_c2 = Pretty.str_of (pretty_classrel sg c1_c2);
   412 fun str_of_arity sg ar = Pretty.str_of (pretty_arity sg ar);
   413 
   414 fun pprint_term sg = Pretty.pprint o Pretty.quote o (pretty_term sg);
   415 fun pprint_typ sg = Pretty.pprint o Pretty.quote o (pretty_typ sg);
   416 
   417 
   418 
   419 (** read types **)  (*exception ERROR*)
   420 
   421 fun err_in_type s =
   422   error ("The error(s) above occurred in type " ^ quote s);
   423 
   424 fun rd_raw_typ syn tsig spaces def_sort str =
   425   intrn_tycons spaces
   426     (Syntax.read_typ syn (Type.get_sort tsig def_sort (intrn_sort spaces)) str
   427       handle ERROR => err_in_type str);
   428 
   429 fun read_raw_typ (sg as Sg (_, {tsig, syn, spaces, ...}), def_sort) str =
   430   (check_stale sg; rd_raw_typ syn tsig spaces def_sort str);
   431 
   432 (*read and certify typ wrt a signature*)
   433 fun read_typ (sg, def_sort) str =
   434   (Type.cert_typ (tsig_of sg) (read_raw_typ (sg, def_sort) str)
   435       handle TYPE (msg, _, _) => (error_msg msg; err_in_type str));
   436 
   437 
   438 
   439 (** certify types and terms **)   (*exception TYPE*)
   440 
   441 val certify_typ = Type.cert_typ o tsig_of;
   442 
   443 (*check for duplicate TVars with distinct sorts*)
   444 fun nodup_TVars (tvars, T) =
   445   (case T of
   446     Type (_, Ts) => nodup_TVars_list (tvars, Ts)
   447   | TFree _ => tvars
   448   | TVar (v as (a, S)) =>
   449       (case assoc_string_int (tvars, a) of
   450         Some S' =>
   451           if S = S' then tvars
   452           else raise TYPE ("Type variable " ^ Syntax.string_of_vname a ^
   453             " has two distinct sorts", [TVar (a, S'), T], [])
   454       | None => v :: tvars))
   455 (*equivalent to foldl nodup_TVars_list, but 3X faster under Poly/ML*)
   456 and nodup_TVars_list (tvars, []) = tvars
   457   | nodup_TVars_list (tvars, T :: Ts) =
   458       nodup_TVars_list (nodup_TVars (tvars, T), Ts);
   459 
   460 (*check for duplicate Vars with distinct types*)
   461 fun nodup_Vars tm =
   462   let
   463     fun nodups vars tvars tm =
   464       (case tm of
   465         Const (c, T) => (vars, nodup_TVars (tvars, T))
   466       | Free (a, T) => (vars, nodup_TVars (tvars, T))
   467       | Var (v as (ixn, T)) =>
   468           (case assoc_string_int (vars, ixn) of
   469             Some T' =>
   470               if T = T' then (vars, nodup_TVars (tvars, T))
   471               else raise TYPE ("Variable " ^ Syntax.string_of_vname ixn ^
   472                 " has two distinct types", [T', T], [])
   473           | None => (v :: vars, tvars))
   474       | Bound _ => (vars, tvars)
   475       | Abs (_, T, t) => nodups vars (nodup_TVars (tvars, T)) t
   476       | s $ t =>
   477           let val (vars',tvars') = nodups vars tvars s in
   478             nodups vars' tvars' t
   479           end);
   480   in nodups [] [] tm; () end;
   481 
   482 
   483 fun mapfilt_atoms f (Abs (_, _, t)) = mapfilt_atoms f t
   484   | mapfilt_atoms f (t $ u) = mapfilt_atoms f t @ mapfilt_atoms f u
   485   | mapfilt_atoms f a = (case f a of Some y => [y] | None => []);
   486 
   487 
   488 fun certify_term sg tm =
   489   let
   490     val _ = check_stale sg;
   491     val tsig = tsig_of sg;
   492 
   493     fun show_const a T = quote a ^ " :: " ^ quote (string_of_typ sg T);
   494 
   495     fun atom_err (Const (a, T)) =
   496         (case const_type sg a of
   497           None => Some ("Undeclared constant " ^ show_const a T)
   498         | Some U =>
   499             if Type.typ_instance (tsig, T, U) then None
   500             else Some ("Illegal type for constant " ^ show_const a T))
   501       | atom_err (Var ((x, i), _)) =
   502           if i < 0 then Some ("Negative index for Var " ^ quote x) else None
   503       | atom_err _ = None;
   504 
   505     val norm_tm =
   506       (case it_term_types (Type.typ_errors tsig) (tm, []) of
   507         [] => map_term_types (Type.norm_typ tsig) tm
   508       | errs => raise TYPE (cat_lines errs, [], [tm]));
   509     val _ = nodup_Vars norm_tm;
   510   in
   511     (case mapfilt_atoms atom_err norm_tm of
   512       [] => (norm_tm, type_of norm_tm, maxidx_of_term norm_tm)
   513     | errs => raise TYPE (cat_lines errs, [], [norm_tm]))
   514   end;
   515 
   516 
   517 
   518 (** infer_types **)         (*exception ERROR*)
   519 
   520 (*
   521   def_type: partial map from indexnames to types (constrains Frees, Vars)
   522   def_sort: partial map from indexnames to sorts (constrains TFrees, TVars)
   523   used: list of already used type variables
   524   freeze: if true then generated parameters are turned into TFrees, else TVars
   525 
   526   termss: lists of alternative parses (only one combination should be type-correct)
   527   typs: expected types
   528 *)
   529 
   530 fun infer_types_simult sg def_type def_sort used freeze args =
   531   let
   532     val tsig = tsig_of sg;
   533     val prt =
   534       setmp Syntax.show_brackets true
   535         (setmp long_names true (pretty_term sg));
   536     val prT = setmp long_names true (pretty_typ sg);
   537 
   538     val termss = foldr multiply (map fst args, [[]]);
   539     val typs =
   540       map (fn (_, T) => certify_typ sg T handle TYPE (msg, _, _) => error msg) args;
   541 
   542     fun infer ts = OK
   543       (Type.infer_types prt prT tsig (const_type sg) def_type def_sort
   544         (intern_const sg) (intern_tycons sg) (intern_sort sg) used freeze typs ts)
   545       handle TYPE (msg, _, _) => Error msg;
   546 
   547     val err_results = map infer termss;
   548     val errs = mapfilter get_error err_results;
   549     val results = mapfilter get_ok err_results;
   550 
   551     val ambiguity = length termss;	(* FIXME !? *)
   552     (* FIXME to syntax.ML!? *)
   553     fun ambig_msg () =
   554       if ambiguity > 1 andalso ambiguity <= ! Syntax.ambiguity_level
   555       then
   556         error_msg "Got more than one parse tree.\n\
   557           \Retry with smaller Syntax.ambiguity_level for more information."
   558       else ();
   559   in
   560     if null results then (ambig_msg (); error (cat_lines errs))
   561     else if length results = 1 then
   562       (if ambiguity > ! Syntax.ambiguity_level then
   563         warning "Fortunately, only one parse tree is type correct.\n\
   564           \You may still want to disambiguate your grammar or your input."
   565       else (); hd results)
   566     else (ambig_msg (); error ("More than one term is type correct:\n" ^
   567       (cat_lines (map (Pretty.string_of o prt) (flat (map fst results))))))
   568   end;
   569 
   570 
   571 fun infer_types sg def_type def_sort used freeze tsT =
   572   apfst hd (infer_types_simult sg def_type def_sort used freeze [tsT]);
   573 
   574 
   575 
   576 (** extend signature **)    (*exception ERROR*)
   577 
   578 (** signature extension functions **)  (*exception ERROR*)
   579 
   580 fun decls_of path name_of mfixs =
   581   map (fn (x, y, mx) => (full path (name_of x mx), y)) mfixs;
   582 
   583 fun no_read _ _ _ decl = decl;
   584 
   585 
   586 (* add default sort *)
   587 
   588 fun ext_defsort int (syn, tsig, ctab, (path, spaces), data) S =
   589   (syn, Type.ext_tsig_defsort tsig (if int then intrn_sort spaces S else S),
   590     ctab, (path, spaces), data);
   591 
   592 
   593 (* add type constructors *)
   594 
   595 fun ext_types (syn, tsig, ctab, (path, spaces), data) types =
   596   let val decls = decls_of path Syntax.type_name types in
   597     (Syntax.extend_type_gram syn types,
   598       Type.ext_tsig_types tsig decls, ctab,
   599       (path, add_names spaces typeK (map fst decls)), data)
   600   end;
   601 
   602 
   603 (* add type abbreviations *)
   604 
   605 fun read_abbr syn tsig spaces (t, vs, rhs_src) =
   606   (t, vs, rd_raw_typ syn tsig spaces (K None) rhs_src)
   607     handle ERROR => error ("in type abbreviation " ^ t);
   608 
   609 fun ext_abbrs rd_abbr (syn, tsig, ctab, (path, spaces), data) abbrs =
   610   let
   611     fun mfix_of (t, vs, _, mx) = (t, length vs, mx);
   612     val syn' = Syntax.extend_type_gram syn (map mfix_of abbrs);
   613 
   614     val abbrs' =
   615       map (fn (t, vs, rhs, mx) =>
   616         (full path (Syntax.type_name t mx), vs, rhs)) abbrs;
   617     val spaces' = add_names spaces typeK (map #1 abbrs');
   618     val decls = map (rd_abbr syn' tsig spaces') abbrs';
   619   in
   620     (syn', Type.ext_tsig_abbrs tsig decls, ctab, (path, spaces'), data)
   621   end;
   622 
   623 fun ext_tyabbrs abbrs = ext_abbrs read_abbr abbrs;
   624 fun ext_tyabbrs_i abbrs = ext_abbrs no_read abbrs;
   625 
   626 
   627 (* add type arities *)
   628 
   629 fun ext_arities int (syn, tsig, ctab, (path, spaces), data) arities =
   630   let
   631     fun intrn_arity (c, Ss, S) =
   632       (intrn spaces typeK c, map (intrn_sort spaces) Ss, intrn_sort spaces S);
   633     val intrn = if int then map intrn_arity else I;
   634     val tsig' = Type.ext_tsig_arities tsig (intrn arities);
   635     val log_types = Type.logical_types tsig';
   636   in
   637     (Syntax.extend_log_types syn log_types, tsig', ctab, (path, spaces), data)
   638   end;
   639 
   640 
   641 (* add term constants and syntax *)
   642 
   643 fun const_name path c mx =
   644   full path (Syntax.const_name c mx);
   645 
   646 fun err_in_const c =
   647   error ("in declaration of constant " ^ quote c);
   648 
   649 fun err_dup_consts cs =
   650   error ("Duplicate declaration of constant(s) " ^ commas_quote cs);
   651 
   652 
   653 fun read_const syn tsig (path, spaces) (c, ty_src, mx) =
   654   (c, rd_raw_typ syn tsig spaces (K None) ty_src, mx)
   655     handle ERROR => err_in_const (const_name path c mx);
   656 
   657 fun ext_cnsts rd_const syn_only prmode (syn, tsig, ctab, (path, spaces), data) raw_consts =
   658   let
   659     fun prep_const (c, ty, mx) =
   660       (c, compress_type (Type.varifyT (Type.cert_typ tsig (Type.no_tvars ty))), mx)
   661         handle TYPE (msg, _, _) =>
   662           (error_msg msg; err_in_const (const_name path c mx));
   663 
   664     val consts = map (prep_const o rd_const syn tsig (path, spaces)) raw_consts;
   665     val decls =
   666       if syn_only then []
   667       else decls_of path Syntax.const_name consts;
   668   in
   669     (Syntax.extend_const_gram syn prmode consts, tsig,
   670       Symtab.extend_new (ctab, decls)
   671         handle Symtab.DUPS cs => err_dup_consts cs,
   672       (path, add_names spaces constK (map fst decls)), data)
   673   end;
   674 
   675 fun ext_consts_i sg = ext_cnsts no_read false ("", true) sg;
   676 fun ext_consts sg = ext_cnsts read_const false ("", true) sg;
   677 fun ext_syntax_i sg = ext_cnsts no_read true ("", true) sg;
   678 fun ext_syntax sg = ext_cnsts read_const true ("", true) sg;
   679 fun ext_modesyntax_i sg (prmode, consts) = ext_cnsts no_read true prmode sg consts;
   680 fun ext_modesyntax sg (prmode, consts) = ext_cnsts read_const true prmode sg consts;
   681 
   682 
   683 (* add type classes *)
   684 
   685 fun const_of_class c = c ^ "_class";
   686 
   687 fun class_of_const c_class =
   688   let
   689     val c = implode (take (size c_class - size "_class", explode c_class));
   690   in
   691     if const_of_class c = c_class then c
   692     else raise TERM ("class_of_const: bad name " ^ quote c_class, [])
   693   end;
   694 
   695 
   696 fun ext_classes int (syn, tsig, ctab, (path, spaces), data) classes =
   697   let
   698     val names = map fst classes;
   699     val consts =
   700       map (fn c => (const_of_class c, a_itselfT --> propT, NoSyn)) names;
   701 
   702     val full_names = map (full path) names;
   703     val spaces' = add_names spaces classK full_names;
   704     val intrn = if int then map (intrn_class spaces') else I;
   705     val classes' =
   706       ListPair.map (fn (c, (_, cs)) => (c, intrn cs)) (full_names, classes);
   707   in
   708     ext_consts_i
   709       (Syntax.extend_consts syn names,
   710         Type.ext_tsig_classes tsig classes', ctab, (path, spaces'), data)
   711     consts
   712   end;
   713 
   714 
   715 (* add to classrel *)
   716 
   717 fun ext_classrel int (syn, tsig, ctab, (path, spaces), data) pairs =
   718   let val intrn = if int then map (pairself (intrn_class spaces)) else I in
   719     (syn, Type.ext_tsig_classrel tsig (intrn pairs), ctab, (path, spaces), data)
   720   end;
   721 
   722 
   723 (* add to syntax *)
   724 
   725 fun ext_syn extfun (syn, tsig, ctab, names, data) args =
   726   (extfun syn args, tsig, ctab, names, data);
   727 
   728 
   729 (* add to path *)
   730 
   731 fun ext_path (syn, tsig, ctab, (path, spaces), data) elem =
   732   let
   733     val path' =
   734       if elem = ".." andalso not (null path) then fst (split_last path)
   735       else if elem = "/" then []
   736       else path @ NameSpace.unpack elem;
   737   in
   738     (syn, tsig, ctab, (path', spaces), data)
   739   end;      
   740 
   741 
   742 (* add to name space *)
   743 
   744 fun ext_space (syn, tsig, ctab, (path, spaces), data) (kind, names) =
   745   (syn, tsig, ctab, (path, add_names spaces kind names), data);
   746 
   747 
   748 (* signature data *)
   749 
   750 fun ext_init_data (syn, tsig, ctab, names, data) (kind, (e, ext, mrg, prt)) =
   751   (syn, tsig, ctab, names, Data.init data kind e ext mrg prt);
   752 
   753 fun ext_put_data (syn, tsig, ctab, names, data) (kind, e) =
   754   (syn, tsig, ctab, names, Data.put data kind e);
   755 
   756 
   757 (* the external interfaces *)
   758 
   759 val add_classes      = extend_sign true (ext_classes true) "#";
   760 val add_classes_i    = extend_sign true (ext_classes false) "#";
   761 val add_classrel     = extend_sign true (ext_classrel true) "#";
   762 val add_classrel_i   = extend_sign true (ext_classrel false) "#";
   763 val add_defsort      = extend_sign true (ext_defsort true) "#";
   764 val add_defsort_i    = extend_sign true (ext_defsort false) "#";
   765 val add_types        = extend_sign true ext_types "#";
   766 val add_tyabbrs      = extend_sign true ext_tyabbrs "#";
   767 val add_tyabbrs_i    = extend_sign true ext_tyabbrs_i "#";
   768 val add_arities      = extend_sign true (ext_arities true) "#";
   769 val add_arities_i    = extend_sign true (ext_arities false) "#";
   770 val add_consts       = extend_sign true ext_consts "#";
   771 val add_consts_i     = extend_sign true ext_consts_i "#";
   772 val add_syntax       = extend_sign true ext_syntax "#";
   773 val add_syntax_i     = extend_sign true ext_syntax_i "#";
   774 val add_modesyntax   = extend_sign true ext_modesyntax "#";
   775 val add_modesyntax_i = extend_sign true ext_modesyntax_i "#";
   776 val add_trfuns       = extend_sign true (ext_syn Syntax.extend_trfuns) "#";
   777 val add_trfunsT      = extend_sign true (ext_syn Syntax.extend_trfunsT) "#";
   778 val add_tokentrfuns  = extend_sign true (ext_syn Syntax.extend_tokentrfuns) "#";
   779 val add_trrules      = extend_sign true (ext_syn Syntax.extend_trrules) "#";
   780 val add_trrules_i    = extend_sign true (ext_syn Syntax.extend_trrules_i) "#";
   781 val add_path         = extend_sign true ext_path "#";
   782 val add_space        = extend_sign true ext_space "#";
   783 val init_data        = extend_sign true ext_init_data "#";
   784 val put_data         = extend_sign true ext_put_data "#";
   785 fun add_name name sg = extend_sign true K name () sg;
   786 fun prep_ext sg      = extend_sign false K "#" () sg;
   787 
   788 
   789 
   790 (** merge signatures **)    	(*exception TERM*)
   791 
   792 (* merge_stamps *)
   793 
   794 fun merge_stamps stamps1 stamps2 =
   795   let val stamps = merge_rev_lists stamps1 stamps2 in
   796     (case duplicates (map ! stamps) of
   797       [] => stamps
   798     | dups => raise TERM ("Attempt to merge different versions of theories "
   799         ^ commas_quote dups, []))
   800   end;
   801 
   802 
   803 (* merge of sg_refs -- trivial only *)
   804 
   805 fun merge_refs (sgr1 as SgRef (Some (ref (sg1 as Sg ({stamps = s1, ...}, _)))),
   806         sgr2 as SgRef (Some (ref (sg2 as Sg ({stamps = s2, ...}, _))))) =
   807       if fast_subsig (sg2, sg1) then sgr1
   808       else if fast_subsig (sg1, sg2) then sgr2
   809       else if subsig (sg2, sg1) then sgr1
   810       else if subsig (sg1, sg2) then sgr2
   811       else (merge_stamps s1 s2; (*check for different versions*)
   812         raise TERM ("Attempt to do non-trivial merge of signatures", []))
   813   | merge_refs _ = sys_error "Sign.merge_refs";
   814 
   815 
   816 (* proper merge *)
   817 
   818 fun merge_aux (sg1, sg2) =
   819   if subsig (sg2, sg1) then sg1
   820   else if subsig (sg1, sg2) then sg2
   821   else if is_draft sg1 orelse is_draft sg2 then
   822     raise TERM ("Attempt to merge draft signatures", [])
   823   else
   824     (*neither is union already; must form union*)
   825     let
   826       val Sg ({id = _, stamps = stamps1}, {self = _, tsig = tsig1, const_tab = const_tab1,
   827         syn = syn1, path = _, spaces = spaces1, data = data1}) = sg1;
   828       val Sg ({id = _, stamps = stamps2}, {self = _, tsig = tsig2, const_tab = const_tab2,
   829         syn = syn2, path = _, spaces = spaces2, data = data2}) = sg2;
   830 
   831       val id = ref "";
   832       val self_ref = ref sg1;                   (*dummy value*)
   833       val self = SgRef (Some self_ref);
   834 
   835       val stamps = merge_stamps stamps1 stamps2;
   836       val tsig = Type.merge_tsigs (tsig1, tsig2);
   837       val const_tab = Symtab.merge (op =) (const_tab1, const_tab2)
   838         handle Symtab.DUPS cs =>
   839           raise TERM ("Incompatible types for constant(s) " ^ commas_quote cs, []);
   840       val syn = Syntax.merge_syntaxes syn1 syn2;
   841 
   842       val path = [];
   843       val kinds = distinct (map fst (spaces1 @ spaces2));
   844       val spaces =
   845         kinds ~~
   846           ListPair.map NameSpace.merge
   847             (map (space_of spaces1) kinds, map (space_of spaces2) kinds);
   848 
   849       val data = Data.merge (data1, data2);
   850 
   851       val sign = make_sign (id, self, tsig, const_tab, syn, path, spaces, data, stamps);
   852     in
   853       self_ref := sign; sign
   854     end;
   855 
   856 fun merge sg1_sg2 =
   857   (case handle_error merge_aux sg1_sg2 of
   858     OK sg => sg
   859   | Error msg => raise TERM (msg, []));
   860 
   861 
   862 
   863 (** partial Pure signature **)
   864 
   865 val dummy_sg = make_sign (ref "", SgRef None, Type.tsig0,
   866   Symtab.null, Syntax.pure_syn, [], [], Data.empty, []);
   867 
   868 val pre_pure =
   869   create_sign (SgRef (Some (ref dummy_sg))) [] "#"
   870     (Syntax.pure_syn, Type.tsig0, Symtab.null, ([], []), Data.empty);
   871 
   872 
   873 end;
   874 
   875 
   876 val long_names = Sign.long_names;