1 /* Symbol table manager for Bison.
3 Copyright (C) 1984, 1989, 2000-2002, 2004-2012 Free Software
6 This file is part of Bison, the GNU Compiler Compiler.
8 This program is free software: you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation, either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
30 /*-------------------------------------------------------------------.
31 | Symbols sorted by tag. Allocated by the first invocation of |
32 | symbols_do, after which no more symbols should be created. |
33 `-------------------------------------------------------------------*/
35 static symbol
**symbols_sorted
= NULL
;
37 /*------------------------.
38 | Distinguished symbols. |
39 `------------------------*/
41 symbol
*errtoken
= NULL
;
42 symbol
*undeftoken
= NULL
;
43 symbol
*endtoken
= NULL
;
44 symbol
*accept
= NULL
;
45 symbol
*startsymbol
= NULL
;
46 location startsymbol_location
;
48 /*---------------------------------------.
49 | Default %destructor's and %printer's. |
50 `---------------------------------------*/
52 static code_props default_tagged_destructor
= CODE_PROPS_NONE_INIT
;
53 static code_props default_tagless_destructor
= CODE_PROPS_NONE_INIT
;
54 static code_props default_tagged_printer
= CODE_PROPS_NONE_INIT
;
55 static code_props default_tagless_printer
= CODE_PROPS_NONE_INIT
;
57 /*---------------------------------.
58 | Create a new symbol, named TAG. |
59 `---------------------------------*/
62 symbol_new (uniqstr tag
, location loc
)
64 symbol
*res
= xmalloc (sizeof *res
);
68 /* If the tag is not a string (starts with a double quote), check
69 that it is valid for Yacc. */
70 if (tag
[0] != '\"' && tag
[0] != '\'' && mbschr (tag
, '-'))
71 yacc_at (loc
, _("POSIX Yacc forbids dashes in symbol names: %s"),
77 res
->type_name
= NULL
;
78 code_props_none_init (&res
->destructor
);
79 code_props_none_init (&res
->printer
);
81 res
->number
= NUMBER_UNDEFINED
;
83 res
->assoc
= undef_assoc
;
84 res
->user_token_number
= USER_NUMBER_UNDEFINED
;
87 res
->class = unknown_sym
;
88 res
->declared
= false;
90 if (nsyms
== SYMBOL_NUMBER_MAXIMUM
)
91 fatal (_("too many symbols in input grammar (limit is %d)"),
92 SYMBOL_NUMBER_MAXIMUM
);
97 /*----------------------------------------.
98 | Create a new semantic type, named TAG. |
99 `----------------------------------------*/
101 static semantic_type
*
102 semantic_type_new (uniqstr tag
)
104 semantic_type
*res
= xmalloc (sizeof *res
);
106 uniqstr_assert (tag
);
108 code_props_none_init (&res
->destructor
);
109 code_props_none_init (&res
->printer
);
119 #define SYMBOL_ATTR_PRINT(Attr) \
121 fprintf (f, " %s { %s }", #Attr, s->Attr)
123 #define SYMBOL_CODE_PRINT(Attr) \
125 fprintf (f, " %s { %s }", #Attr, s->Attr.code)
128 symbol_print (symbol
*s
, FILE *f
)
132 fprintf (f
, "\"%s\"", s
->tag
);
133 SYMBOL_ATTR_PRINT (type_name
);
134 SYMBOL_CODE_PRINT (destructor
);
135 SYMBOL_CODE_PRINT (printer
);
138 fprintf (f
, "<NULL>");
141 #undef SYMBOL_ATTR_PRINT
142 #undef SYMBOL_CODE_PRINT
144 /*------------------------------------------------------------------.
145 | Complain that S's WHAT is redeclared at SECOND, and was first set |
147 `------------------------------------------------------------------*/
150 symbol_redeclaration (symbol
*s
, const char *what
, location first
,
154 complain_at_indent (second
, &i
, _("%s redeclaration for %s"), what
, s
->tag
);
156 complain_at_indent (first
, &i
, _("previous declaration"));
160 semantic_type_redeclaration (semantic_type
*s
, const char *what
, location first
,
164 complain_at_indent (second
, &i
, _("%s redeclaration for <%s>"), what
, s
->tag
);
166 complain_at_indent (first
, &i
, _("previous declaration"));
171 /*-----------------------------------------------------------------.
172 | Set the TYPE_NAME associated with SYM. Does nothing if passed 0 |
174 `-----------------------------------------------------------------*/
177 symbol_type_set (symbol
*sym
, uniqstr type_name
, location loc
)
182 symbol_redeclaration (sym
, "%type", sym
->type_location
, loc
);
183 uniqstr_assert (type_name
);
184 sym
->type_name
= type_name
;
185 sym
->type_location
= loc
;
189 /*-----------------------------------------.
190 | Set the DESTRUCTOR associated with SYM. |
191 `-----------------------------------------*/
194 symbol_destructor_set (symbol
*sym
, code_props
const *destructor
)
196 if (sym
->destructor
.code
)
197 symbol_redeclaration (sym
, "%destructor", sym
->destructor
.location
,
198 destructor
->location
);
199 sym
->destructor
= *destructor
;
202 /*------------------------------------------.
203 | Set the DESTRUCTOR associated with TYPE. |
204 `------------------------------------------*/
207 semantic_type_destructor_set (semantic_type
*type
,
208 code_props
const *destructor
)
210 if (type
->destructor
.code
)
211 semantic_type_redeclaration (type
, "%destructor",
212 type
->destructor
.location
,
213 destructor
->location
);
214 type
->destructor
= *destructor
;
217 /*---------------------------------------.
218 | Get the computed %destructor for SYM. |
219 `---------------------------------------*/
222 symbol_destructor_get (symbol
const *sym
)
224 /* Per-symbol %destructor. */
225 if (sym
->destructor
.code
)
226 return &sym
->destructor
;
228 /* Per-type %destructor. */
231 code_props
const *destructor
=
232 &semantic_type_get (sym
->type_name
)->destructor
;
233 if (destructor
->code
)
237 /* Apply default %destructor's only to user-defined symbols. */
238 if (sym
->tag
[0] == '$' || sym
== errtoken
)
239 return &code_props_none
;
242 return &default_tagged_destructor
;
243 return &default_tagless_destructor
;
246 /*--------------------------------------.
247 | Set the PRINTER associated with SYM. |
248 `--------------------------------------*/
251 symbol_printer_set (symbol
*sym
, code_props
const *printer
)
253 if (sym
->printer
.code
)
254 symbol_redeclaration (sym
, "%printer",
255 sym
->printer
.location
, printer
->location
);
256 sym
->printer
= *printer
;
259 /*---------------------------------------.
260 | Set the PRINTER associated with TYPE. |
261 `---------------------------------------*/
264 semantic_type_printer_set (semantic_type
*type
, code_props
const *printer
)
266 if (type
->printer
.code
)
267 semantic_type_redeclaration (type
, "%printer",
268 type
->printer
.location
, printer
->location
);
269 type
->printer
= *printer
;
272 /*------------------------------------.
273 | Get the computed %printer for SYM. |
274 `------------------------------------*/
277 symbol_printer_get (symbol
const *sym
)
279 /* Per-symbol %printer. */
280 if (sym
->printer
.code
)
281 return &sym
->printer
;
283 /* Per-type %printer. */
286 code_props
const *printer
= &semantic_type_get (sym
->type_name
)->printer
;
291 /* Apply the default %printer only to user-defined symbols. */
292 if (sym
->tag
[0] == '$' || sym
== errtoken
)
293 return &code_props_none
;
296 return &default_tagged_printer
;
297 return &default_tagless_printer
;
300 /*-----------------------------------------------------------------.
301 | Set the PRECEDENCE associated with SYM. Does nothing if invoked |
302 | with UNDEF_ASSOC as ASSOC. |
303 `-----------------------------------------------------------------*/
306 symbol_precedence_set (symbol
*sym
, int prec
, assoc a
, location loc
)
308 if (a
!= undef_assoc
)
311 symbol_redeclaration (sym
, assoc_to_string (a
), sym
->prec_location
,
315 sym
->prec_location
= loc
;
318 /* Only terminals have a precedence. */
319 symbol_class_set (sym
, token_sym
, loc
, false);
323 /*------------------------------------.
324 | Set the CLASS associated with SYM. |
325 `------------------------------------*/
328 symbol_class_set (symbol
*sym
, symbol_class
class, location loc
, bool declaring
)
330 if (sym
->class != unknown_sym
&& sym
->class != class)
332 complain_at (loc
, _("symbol %s redefined"), sym
->tag
);
333 sym
->declared
= false;
336 if (class == nterm_sym
&& sym
->class != nterm_sym
)
337 sym
->number
= nvars
++;
338 else if (class == token_sym
&& sym
->number
== NUMBER_UNDEFINED
)
339 sym
->number
= ntokens
++;
346 warn_at (loc
, _("symbol %s redeclared"), sym
->tag
);
347 sym
->declared
= true;
352 /*------------------------------------------------.
353 | Set the USER_TOKEN_NUMBER associated with SYM. |
354 `------------------------------------------------*/
357 symbol_user_token_number_set (symbol
*sym
, int user_token_number
, location loc
)
359 int *user_token_numberp
;
361 if (sym
->user_token_number
!= USER_NUMBER_HAS_STRING_ALIAS
)
362 user_token_numberp
= &sym
->user_token_number
;
364 user_token_numberp
= &sym
->alias
->user_token_number
;
365 if (*user_token_numberp
!= USER_NUMBER_UNDEFINED
366 && *user_token_numberp
!= user_token_number
)
367 complain_at (loc
, _("redefining user token number of %s"), sym
->tag
);
369 *user_token_numberp
= user_token_number
;
370 /* User defined $end token? */
371 if (user_token_number
== 0)
374 /* It is always mapped to 0, so it was already counted in
376 if (endtoken
->number
!= NUMBER_UNDEFINED
)
378 endtoken
->number
= 0;
383 /*----------------------------------------------------------.
384 | If SYM is not defined, report an error, and consider it a |
386 `----------------------------------------------------------*/
389 symbol_check_defined (symbol
*sym
)
391 if (sym
->class == unknown_sym
)
395 _("symbol %s is used, but is not defined as a token and has no rules"),
397 sym
->class = nterm_sym
;
398 sym
->number
= nvars
++;
405 symbol_check_defined_processor (void *sym
, void *null ATTRIBUTE_UNUSED
)
407 return symbol_check_defined (sym
);
412 symbol_make_alias (symbol
*sym
, symbol
*str
, location loc
)
415 warn_at (loc
, _("symbol %s used more than once as a literal string"),
418 warn_at (loc
, _("symbol %s given more than one literal string"),
422 str
->class = token_sym
;
423 str
->user_token_number
= sym
->user_token_number
;
424 sym
->user_token_number
= USER_NUMBER_HAS_STRING_ALIAS
;
427 str
->number
= sym
->number
;
428 symbol_type_set (str
, sym
->type_name
, loc
);
433 /*---------------------------------------------------------.
434 | Check that THIS, and its alias, have same precedence and |
436 `---------------------------------------------------------*/
439 symbol_check_alias_consistency (symbol
*this)
442 symbol
*str
= this->alias
;
444 /* Check only the symbol in the symbol-string pair. */
446 && this->user_token_number
== USER_NUMBER_HAS_STRING_ALIAS
))
449 if (str
->type_name
!= sym
->type_name
)
452 symbol_type_set (sym
, str
->type_name
, str
->type_location
);
454 symbol_type_set (str
, sym
->type_name
, sym
->type_location
);
458 if (str
->destructor
.code
|| sym
->destructor
.code
)
460 if (str
->destructor
.code
)
461 symbol_destructor_set (sym
, &str
->destructor
);
463 symbol_destructor_set (str
, &sym
->destructor
);
466 if (str
->printer
.code
|| sym
->printer
.code
)
468 if (str
->printer
.code
)
469 symbol_printer_set (sym
, &str
->printer
);
471 symbol_printer_set (str
, &sym
->printer
);
474 if (sym
->prec
|| str
->prec
)
477 symbol_precedence_set (sym
, str
->prec
, str
->assoc
,
480 symbol_precedence_set (str
, sym
->prec
, sym
->assoc
,
486 symbol_check_alias_consistency_processor (void *this,
487 void *null ATTRIBUTE_UNUSED
)
489 symbol_check_alias_consistency (this);
494 /*-------------------------------------------------------------------.
495 | Assign a symbol number, and write the definition of the token name |
496 | into FDEFINES. Put in SYMBOLS. |
497 `-------------------------------------------------------------------*/
500 symbol_pack (symbol
*this)
502 aver (this->number
!= NUMBER_UNDEFINED
);
503 if (this->class == nterm_sym
)
504 this->number
+= ntokens
;
505 else if (this->user_token_number
== USER_NUMBER_HAS_STRING_ALIAS
)
508 symbols
[this->number
] = this;
513 symbol_pack_processor (void *this, void *null ATTRIBUTE_UNUSED
)
515 return symbol_pack (this);
520 user_token_number_redeclaration (int num
, symbol
*first
, symbol
*second
)
523 /* User token numbers are not assigned during the parsing, but in a
524 second step, via a traversal of the symbol table sorted on tag.
526 However, error messages make more sense if we keep the first
527 declaration first. */
528 if (location_cmp (first
->location
, second
->location
) > 0)
534 complain_at_indent (second
->location
, &i
,
535 _("user token number %d redeclaration for %s"),
537 complain_at_indent (first
->location
, &i
,
538 _("previous declaration for %s"),
542 /*--------------------------------------------------.
543 | Put THIS in TOKEN_TRANSLATIONS if it is a token. |
544 `--------------------------------------------------*/
547 symbol_translation (symbol
*this)
550 if (this->class == token_sym
551 && this->user_token_number
!= USER_NUMBER_HAS_STRING_ALIAS
)
553 /* A token which translation has already been set? */
554 if (token_translations
[this->user_token_number
] != undeftoken
->number
)
555 user_token_number_redeclaration
556 (this->user_token_number
,
557 symbols
[token_translations
[this->user_token_number
]],
560 token_translations
[this->user_token_number
] = this->number
;
567 symbol_translation_processor (void *this, void *null ATTRIBUTE_UNUSED
)
569 return symbol_translation (this);
573 /*---------------------------------------.
574 | Symbol and semantic type hash tables. |
575 `---------------------------------------*/
577 /* Initial capacity of symbol and semantic type hash table. */
578 #define HT_INITIAL_CAPACITY 257
580 static struct hash_table
*symbol_table
= NULL
;
581 static struct hash_table
*semantic_type_table
= NULL
;
584 hash_compare_symbol (const symbol
*m1
, const symbol
*m2
)
586 /* Since tags are unique, we can compare the pointers themselves. */
587 return UNIQSTR_EQ (m1
->tag
, m2
->tag
);
591 hash_compare_semantic_type (const semantic_type
*m1
, const semantic_type
*m2
)
593 /* Since names are unique, we can compare the pointers themselves. */
594 return UNIQSTR_EQ (m1
->tag
, m2
->tag
);
598 hash_symbol_comparator (void const *m1
, void const *m2
)
600 return hash_compare_symbol (m1
, m2
);
604 hash_semantic_type_comparator (void const *m1
, void const *m2
)
606 return hash_compare_semantic_type (m1
, m2
);
610 hash_symbol (const symbol
*m
, size_t tablesize
)
612 /* Since tags are unique, we can hash the pointer itself. */
613 return ((uintptr_t) m
->tag
) % tablesize
;
617 hash_semantic_type (const semantic_type
*m
, size_t tablesize
)
619 /* Since names are unique, we can hash the pointer itself. */
620 return ((uintptr_t) m
->tag
) % tablesize
;
624 hash_symbol_hasher (void const *m
, size_t tablesize
)
626 return hash_symbol (m
, tablesize
);
630 hash_semantic_type_hasher (void const *m
, size_t tablesize
)
632 return hash_semantic_type (m
, tablesize
);
635 /*-------------------------------.
636 | Create the symbol hash table. |
637 `-------------------------------*/
642 symbol_table
= hash_initialize (HT_INITIAL_CAPACITY
,
645 hash_symbol_comparator
,
647 semantic_type_table
= hash_initialize (HT_INITIAL_CAPACITY
,
649 hash_semantic_type_hasher
,
650 hash_semantic_type_comparator
,
655 /*----------------------------------------------------------------.
656 | Find the symbol named KEY, and return it. If it does not exist |
658 `----------------------------------------------------------------*/
661 symbol_from_uniqstr (const uniqstr key
, location loc
)
667 entry
= hash_lookup (symbol_table
, &probe
);
671 /* First insertion in the hash. */
672 aver (!symbols_sorted
);
673 entry
= symbol_new (key
, loc
);
674 if (!hash_insert (symbol_table
, entry
))
681 /*-----------------------------------------------------------------------.
682 | Find the semantic type named KEY, and return it. If it does not exist |
684 `-----------------------------------------------------------------------*/
687 semantic_type_from_uniqstr (const uniqstr key
)
690 semantic_type
*entry
;
693 entry
= hash_lookup (semantic_type_table
, &probe
);
697 /* First insertion in the hash. */
698 entry
= semantic_type_new (key
);
699 if (!hash_insert (semantic_type_table
, entry
))
706 /*----------------------------------------------------------------.
707 | Find the symbol named KEY, and return it. If it does not exist |
709 `----------------------------------------------------------------*/
712 symbol_get (const char *key
, location loc
)
714 return symbol_from_uniqstr (uniqstr_new (key
), loc
);
718 /*-----------------------------------------------------------------------.
719 | Find the semantic type named KEY, and return it. If it does not exist |
721 `-----------------------------------------------------------------------*/
724 semantic_type_get (const char *key
)
726 return semantic_type_from_uniqstr (uniqstr_new (key
));
730 /*------------------------------------------------------------------.
731 | Generate a dummy nonterminal, whose name cannot conflict with the |
733 `------------------------------------------------------------------*/
736 dummy_symbol_get (location loc
)
738 /* Incremented for each generated symbol. */
739 static int dummy_count
= 0;
740 static char buf
[256];
744 sprintf (buf
, "$@%d", ++dummy_count
);
745 sym
= symbol_get (buf
, loc
);
746 sym
->class = nterm_sym
;
747 sym
->number
= nvars
++;
752 symbol_is_dummy (const symbol
*sym
)
754 return sym
->tag
[0] == '@' || (sym
->tag
[0] == '$' && sym
->tag
[1] == '@');
757 /*-------------------.
758 | Free the symbols. |
759 `-------------------*/
764 hash_free (symbol_table
);
765 hash_free (semantic_type_table
);
767 free (symbols_sorted
);
771 /*---------------------------------------------------------------.
772 | Look for undefined symbols, report an error, and consider them |
774 `---------------------------------------------------------------*/
777 symbols_cmp (symbol
const *a
, symbol
const *b
)
779 return strcmp (a
->tag
, b
->tag
);
783 symbols_cmp_qsort (void const *a
, void const *b
)
785 return symbols_cmp (*(symbol
* const *)a
, *(symbol
* const *)b
);
789 symbols_do (Hash_processor processor
, void *processor_data
)
791 size_t count
= hash_get_n_entries (symbol_table
);
794 symbols_sorted
= xnmalloc (count
, sizeof *symbols_sorted
);
795 hash_get_entries (symbol_table
, (void**)symbols_sorted
, count
);
796 qsort (symbols_sorted
, count
, sizeof *symbols_sorted
,
801 for (i
= 0; i
< count
; ++i
)
802 processor (symbols_sorted
[i
], processor_data
);
806 /*--------------------------------------------------------------.
807 | Check that all the symbols are defined. Report any undefined |
808 | symbols and consider them nonterminals. |
809 `--------------------------------------------------------------*/
812 symbols_check_defined (void)
814 symbols_do (symbol_check_defined_processor
, NULL
);
817 /*------------------------------------------------------------------.
818 | Set TOKEN_TRANSLATIONS. Check that no two symbols share the same |
820 `------------------------------------------------------------------*/
823 symbols_token_translations_init (void)
825 bool num_256_available_p
= true;
828 /* Find the highest user token number, and whether 256, the POSIX
829 preferred user token number for the error token, is used. */
830 max_user_token_number
= 0;
831 for (i
= 0; i
< ntokens
; ++i
)
833 symbol
*this = symbols
[i
];
834 if (this->user_token_number
!= USER_NUMBER_UNDEFINED
)
836 if (this->user_token_number
> max_user_token_number
)
837 max_user_token_number
= this->user_token_number
;
838 if (this->user_token_number
== 256)
839 num_256_available_p
= false;
843 /* If 256 is not used, assign it to error, to follow POSIX. */
844 if (num_256_available_p
845 && errtoken
->user_token_number
== USER_NUMBER_UNDEFINED
)
846 errtoken
->user_token_number
= 256;
848 /* Set the missing user numbers. */
849 if (max_user_token_number
< 256)
850 max_user_token_number
= 256;
852 for (i
= 0; i
< ntokens
; ++i
)
854 symbol
*this = symbols
[i
];
855 if (this->user_token_number
== USER_NUMBER_UNDEFINED
)
856 this->user_token_number
= ++max_user_token_number
;
857 if (this->user_token_number
> max_user_token_number
)
858 max_user_token_number
= this->user_token_number
;
861 token_translations
= xnmalloc (max_user_token_number
+ 1,
862 sizeof *token_translations
);
864 /* Initialize all entries for literal tokens to 2, the internal
865 token number for $undefined, which represents all invalid inputs.
867 for (i
= 0; i
< max_user_token_number
+ 1; i
++)
868 token_translations
[i
] = undeftoken
->number
;
869 symbols_do (symbol_translation_processor
, NULL
);
873 /*----------------------------------------------------------------.
874 | Assign symbol numbers, and write definition of token names into |
875 | FDEFINES. Set up vectors SYMBOL_TABLE, TAGS of symbols. |
876 `----------------------------------------------------------------*/
881 symbols_do (symbol_check_alias_consistency_processor
, NULL
);
883 symbols
= xcalloc (nsyms
, sizeof *symbols
);
884 symbols_do (symbol_pack_processor
, NULL
);
886 /* Aliases leave empty slots in symbols, so remove them. */
890 int nsyms_old
= nsyms
;
891 for (writei
= 0, readi
= 0; readi
< nsyms_old
; readi
+= 1)
893 if (symbols
[readi
] == NULL
)
900 symbols
[writei
] = symbols
[readi
];
901 symbols
[writei
]->number
= writei
;
902 if (symbols
[writei
]->alias
)
903 symbols
[writei
]->alias
->number
= writei
;
908 symbols
= xnrealloc (symbols
, nsyms
, sizeof *symbols
);
910 symbols_token_translations_init ();
912 if (startsymbol
->class == unknown_sym
)
913 fatal_at (startsymbol_location
,
914 _("the start symbol %s is undefined"),
916 else if (startsymbol
->class == token_sym
)
917 fatal_at (startsymbol_location
,
918 _("the start symbol %s is a token"),
923 /*--------------------------------------------------.
924 | Set default tagged/tagless %destructor/%printer. |
925 `--------------------------------------------------*/
928 default_tagged_destructor_set (code_props
const *destructor
)
930 if (default_tagged_destructor
.code
)
933 complain_at_indent (destructor
->location
, &i
,
934 _("redeclaration for default tagged %%destructor"));
936 complain_at_indent (default_tagged_destructor
.location
, &i
,
937 _("previous declaration"));
939 default_tagged_destructor
= *destructor
;
943 default_tagless_destructor_set (code_props
const *destructor
)
945 if (default_tagless_destructor
.code
)
948 complain_at_indent (destructor
->location
, &i
,
949 _("redeclaration for default tagless %%destructor"));
951 complain_at_indent (default_tagless_destructor
.location
, &i
,
952 _("previous declaration"));
954 default_tagless_destructor
= *destructor
;
958 default_tagged_printer_set (code_props
const *printer
)
960 if (default_tagged_printer
.code
)
963 complain_at_indent (printer
->location
, &i
,
964 _("redeclaration for default tagged %%printer"));
966 complain_at_indent (default_tagged_printer
.location
, &i
,
967 _("previous declaration"));
969 default_tagged_printer
= *printer
;
973 default_tagless_printer_set (code_props
const *printer
)
975 if (default_tagless_printer
.code
)
978 complain_at_indent (printer
->location
, &i
,
979 _("redeclaration for default tagless %%printer"));
981 complain_at_indent (default_tagless_printer
.location
, &i
,
982 _("previous declaration"));
984 default_tagless_printer
= *printer
;