b4_args is more general than only C++.
[bison.git] / src / scan-code.l
CommitLineData
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1/* Bison Action Scanner -*- C -*-
2
58bd33b7 3 Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.
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4
5 This file is part of Bison, the GNU Compiler Compiler.
6
f16b0819 7 This program is free software: you can redistribute it and/or modify
e9071366 8 it under the terms of the GNU General Public License as published by
f16b0819 9 the Free Software Foundation, either version 3 of the License, or
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10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
f16b0819 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
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19
20%option debug nodefault nounput noyywrap never-interactive
21%option prefix="code_" outfile="lex.yy.c"
22
23%{
24/* Work around a bug in flex 2.5.31. See Debian bug 333231
25 <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=333231>. */
26#undef code_wrap
27#define code_wrap() 1
28
29#define FLEX_PREFIX(Id) code_ ## Id
0305d25e 30#include <src/flex-scanner.h>
f9bfc42a 31
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32#include <src/complain.h>
33#include <src/reader.h>
34#include <src/getargs.h>
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35#include <get-errno.h>
36#include <quote.h>
37
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38#include <src/scan-code.h>
39#include <src/symlist.h>
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40
41/* The current calling start condition: SC_RULE_ACTION or
42 SC_SYMBOL_ACTION. */
28e52c0d 43# define YY_DECL static char *code_lex (code_props *self, int sc_context)
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44YY_DECL;
45
46#define YY_USER_ACTION location_compute (loc, &loc->end, yytext, yyleng);
47
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48static void handle_action_dollar (symbol_list *rule, char *cp,
49 location dollar_loc);
50static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
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51static location the_location;
52static location *loc = &the_location;
ddc8ede1 53
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54/* A string representing the most recent translation. */
55static char *last_string;
56
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57/* True if an untyped $$ or $n was seen. */
58static bool untyped_var_seen;
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59%}
60 /* C and C++ comments in code. */
61%x SC_COMMENT SC_LINE_COMMENT
62 /* Strings and characters in code. */
63%x SC_STRING SC_CHARACTER
64 /* Whether in a rule or symbol action. Specifies the translation
65 of $ and @. */
66%x SC_RULE_ACTION SC_SYMBOL_ACTION
67
68
69/* POSIX says that a tag must be both an id and a C union member, but
70 historically almost any character is allowed in a tag. We disallow
71 NUL and newline, as this simplifies our implementation. */
72tag [^\0\n>]+
73
74/* Zero or more instances of backslash-newline. Following GCC, allow
75 white space between the backslash and the newline. */
76splice (\\[ \f\t\v]*\n)*
77
78%%
79
80%{
2346344a 81 /* Nesting level of the current code in braces. */
4f82b42a 82 int braces_level = 0;
2346344a 83
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84 /* This scanner is special: it is invoked only once, henceforth
85 is expected to return only once. This initialization is
86 therefore done once per action to translate. */
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87 aver (sc_context == SC_SYMBOL_ACTION
88 || sc_context == SC_RULE_ACTION
89 || sc_context == INITIAL);
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90 BEGIN sc_context;
91%}
92
93 /*------------------------------------------------------------.
94 | Scanning a C comment. The initial `/ *' is already eaten. |
95 `------------------------------------------------------------*/
96
97<SC_COMMENT>
98{
99 "*"{splice}"/" STRING_GROW; BEGIN sc_context;
100}
101
102
103 /*--------------------------------------------------------------.
104 | Scanning a line comment. The initial `//' is already eaten. |
105 `--------------------------------------------------------------*/
106
107<SC_LINE_COMMENT>
108{
109 "\n" STRING_GROW; BEGIN sc_context;
110 {splice} STRING_GROW;
111}
112
113
114 /*--------------------------------------------.
115 | Scanning user-code characters and strings. |
116 `--------------------------------------------*/
117
118<SC_CHARACTER,SC_STRING>
119{
120 {splice}|\\{splice}. STRING_GROW;
121}
122
123<SC_CHARACTER>
124{
125 "'" STRING_GROW; BEGIN sc_context;
126}
127
128<SC_STRING>
129{
130 "\"" STRING_GROW; BEGIN sc_context;
131}
132
133
134<SC_RULE_ACTION,SC_SYMBOL_ACTION>{
135 "'" {
136 STRING_GROW;
137 BEGIN SC_CHARACTER;
138 }
139 "\"" {
140 STRING_GROW;
141 BEGIN SC_STRING;
142 }
143 "/"{splice}"*" {
144 STRING_GROW;
145 BEGIN SC_COMMENT;
146 }
147 "/"{splice}"/" {
148 STRING_GROW;
149 BEGIN SC_LINE_COMMENT;
150 }
151}
152
153<SC_RULE_ACTION>
154{
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155 "$"("<"{tag}">")?(-?[0-9]+|"$") {
156 handle_action_dollar (self->rule, yytext, *loc);
157 }
158 "@"(-?[0-9]+|"$") {
159 handle_action_at (self->rule, yytext, *loc);
160 }
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161
162 "$" {
163 warn_at (*loc, _("stray `$'"));
164 obstack_sgrow (&obstack_for_string, "$][");
165 }
166 "@" {
167 warn_at (*loc, _("stray `@'"));
168 obstack_sgrow (&obstack_for_string, "@@");
169 }
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170
171 "{" STRING_GROW; ++braces_level;
172 "}" {
58bd33b7 173 bool outer_brace = --braces_level == 0;
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174
175 /* As an undocumented Bison extension, append `;' before the last
176 brace in braced code, so that the user code can omit trailing
177 `;'. But do not append `;' if emulating Yacc, since Yacc does
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178 not append one. Also, some output languages (like Java) do not
179 accept an extra semicolon, so don't append if the user specified
180 a skeleton or language.
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181
182 FIXME: Bison should warn if a semicolon seems to be necessary
183 here, and should omit the semicolon if it seems unnecessary
184 (e.g., after ';', '{', or '}', each followed by comments or
185 white space). Such a warning shouldn't depend on --yacc; it
186 should depend on a new --pedantic option, which would cause
187 Bison to warn if it detects an extension to POSIX. --pedantic
188 should also diagnose other Bison extensions like %yacc.
189 Perhaps there should also be a GCC-style --pedantic-errors
190 option, so that such warnings are diagnosed as errors. */
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191 if (outer_brace && !yacc_flag && language_prio == default_prio
192 && skeleton_prio == default_prio)
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193 obstack_1grow (&obstack_for_string, ';');
194
195 STRING_GROW;
196 }
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197}
198
199<SC_SYMBOL_ACTION>
200{
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201 "$$" {
202 obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar[");
203 self->is_value_used = true;
204 }
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205 "@$" {
206 obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
207 locations_flag = true;
208 }
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209}
210
211
212 /*-----------------------------------------.
213 | Escape M4 quoting characters in C code. |
214 `-----------------------------------------*/
215
216<*>
217{
218 \$ obstack_sgrow (&obstack_for_string, "$][");
219 \@ obstack_sgrow (&obstack_for_string, "@@");
220 \[ obstack_sgrow (&obstack_for_string, "@{");
221 \] obstack_sgrow (&obstack_for_string, "@}");
222}
223
224 /*-----------------------------------------------------.
225 | By default, grow the string obstack with the input. |
226 `-----------------------------------------------------*/
227
228<*>.|\n STRING_GROW;
229
230 /* End of processing. */
231<*><<EOF>> {
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232 STRING_FINISH;
233 return last_string;
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234 }
235
236%%
237
238/* Keeps track of the maximum number of semantic values to the left of
239 a handle (those referenced by $0, $-1, etc.) are required by the
240 semantic actions of this grammar. */
241int max_left_semantic_context = 0;
242
243
244/*------------------------------------------------------------------.
245| TEXT is pointing to a wannabee semantic value (i.e., a `$'). |
246| |
247| Possible inputs: $[<TYPENAME>]($|integer) |
248| |
249| Output to OBSTACK_FOR_STRING a reference to this semantic value. |
250`------------------------------------------------------------------*/
251
252static void
4210cd0b 253handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
e9071366 254{
28e52c0d 255 char const *type_name = NULL;
e9071366 256 char *cp = text + 1;
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257 symbol_list *effective_rule;
258 int effective_rule_length;
259
260 if (rule->midrule_parent_rule)
261 {
262 effective_rule = rule->midrule_parent_rule;
263 effective_rule_length = rule->midrule_parent_rhs_index - 1;
264 }
265 else
266 {
267 effective_rule = rule;
268 effective_rule_length = symbol_list_length (rule->next);
269 }
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270
271 /* Get the type name if explicit. */
272 if (*cp == '<')
273 {
274 type_name = ++cp;
275 while (*cp != '>')
276 ++cp;
277 *cp = '\0';
278 ++cp;
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279 if (untyped_var_seen)
280 complain_at (dollar_loc, _("explicit type given in untyped grammar"));
281 tag_seen = true;
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282 }
283
284 if (*cp == '$')
285 {
286 if (!type_name)
4210cd0b 287 type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
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288
289 if (!type_name)
ad6b1efa 290 {
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291 if (union_seen | tag_seen)
292 {
293 if (rule->midrule_parent_rule)
294 complain_at (dollar_loc,
295 _("$$ for the midrule at $%d of `%s'"
296 " has no declared type"),
297 rule->midrule_parent_rhs_index,
3be03b13 298 effective_rule->content.sym->tag);
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299 else
300 complain_at (dollar_loc, _("$$ of `%s' has no declared type"),
3be03b13 301 rule->content.sym->tag);
ddc8ede1 302 }
ad6b1efa 303 else
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304 untyped_var_seen = true;
305 type_name = "";
ad6b1efa 306 }
ddc8ede1 307
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308 obstack_fgrow1 (&obstack_for_string,
309 "]b4_lhs_value([%s])[", type_name);
f6857bbf 310 rule->action_props.is_value_used = true;
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311 }
312 else
313 {
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314 long int num = strtol (cp, NULL, 10);
315
316 if (1 - INT_MAX + effective_rule_length <= num
317 && num <= effective_rule_length)
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318 {
319 int n = num;
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320 if (max_left_semantic_context < 1 - n)
321 max_left_semantic_context = 1 - n;
322 if (!type_name && 0 < n)
0c8e079f 323 type_name =
ffa4ba3a 324 symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
e9071366 325 if (!type_name)
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326 {
327 if (union_seen | tag_seen)
328 complain_at (dollar_loc, _("$%d of `%s' has no declared type"),
3be03b13 329 n, effective_rule->content.sym->tag);
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330 else
331 untyped_var_seen = true;
332 type_name = "";
333 }
334
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335 obstack_fgrow3 (&obstack_for_string,
336 "]b4_rhs_value(%d, %d, [%s])[",
ffa4ba3a 337 effective_rule_length, n, type_name);
28e52c0d 338 if (n > 0)
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339 symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
340 true;
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341 }
342 else
0c8e079f 343 complain_at (dollar_loc, _("integer out of range: %s"), quote (text));
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344 }
345}
346
347
348/*------------------------------------------------------.
349| TEXT is a location token (i.e., a `@...'). Output to |
350| OBSTACK_FOR_STRING a reference to this location. |
351`------------------------------------------------------*/
352
353static void
4210cd0b 354handle_action_at (symbol_list *rule, char *text, location at_loc)
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355{
356 char *cp = text + 1;
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357 int effective_rule_length =
358 (rule->midrule_parent_rule
359 ? rule->midrule_parent_rhs_index - 1
360 : symbol_list_length (rule->next));
ffa4ba3a 361
4f82b42a 362 locations_flag = true;
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363
364 if (*cp == '$')
365 obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
366 else
367 {
ddc8ede1 368 long int num = strtol (cp, NULL, 10);
e9071366 369
ddc8ede1
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370 if (1 - INT_MAX + effective_rule_length <= num
371 && num <= effective_rule_length)
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372 {
373 int n = num;
374 obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
ffa4ba3a 375 effective_rule_length, n);
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376 }
377 else
0c8e079f 378 complain_at (at_loc, _("integer out of range: %s"), quote (text));
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379 }
380}
381
382
383/*-------------------------.
384| Initialize the scanner. |
385`-------------------------*/
386
28e52c0d 387/* Translate the dollars and ats in \a self, in the context \a sc_context
ddc8ede1 388 (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL). */
e9071366 389
eb095650 390static char const *
28e52c0d 391translate_action (code_props *self, int sc_context)
e9071366 392{
2ce4ed68 393 char *res;
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394 static bool initialized = false;
395 if (!initialized)
396 {
397 obstack_init (&obstack_for_string);
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398 yy_flex_debug = 0;
399 initialized = true;
400 }
401
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402 loc->start = loc->end = self->location.start;
403 yy_switch_to_buffer (yy_scan_string (self->code));
404 res = code_lex (self, sc_context);
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405 yy_delete_buffer (YY_CURRENT_BUFFER);
406
407 return res;
408}
409
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410/*------------------------------------------------------------------------.
411| Implementation of the public interface as documented in "scan-code.h". |
412`------------------------------------------------------------------------*/
413
414void
415code_props_none_init (code_props *self)
76290368 416{
28e52c0d 417 *self = code_props_none;
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418}
419
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420code_props const code_props_none = CODE_PROPS_NONE_INIT;
421
422void
423code_props_plain_init (code_props *self, char const *code, location code_loc)
76290368 424{
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425 self->kind = CODE_PROPS_PLAIN;
426 self->code = code;
427 self->location = code_loc;
428 self->is_value_used = false;
429 self->rule = NULL;
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430}
431
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432void
433code_props_symbol_action_init (code_props *self, char const *code,
434 location code_loc)
e9071366 435{
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436 self->kind = CODE_PROPS_SYMBOL_ACTION;
437 self->code = code;
438 self->location = code_loc;
439 self->is_value_used = false;
440 self->rule = NULL;
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441}
442
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443void
444code_props_rule_action_init (code_props *self, char const *code,
445 location code_loc, symbol_list *rule)
446{
447 self->kind = CODE_PROPS_RULE_ACTION;
448 self->code = code;
449 self->location = code_loc;
450 self->is_value_used = false;
451 self->rule = rule;
452}
453
454void
455code_props_translate_code (code_props *self)
456{
457 switch (self->kind)
458 {
459 case CODE_PROPS_NONE:
460 break;
461 case CODE_PROPS_PLAIN:
462 self->code = translate_action (self, INITIAL);
463 break;
464 case CODE_PROPS_SYMBOL_ACTION:
465 self->code = translate_action (self, SC_SYMBOL_ACTION);
466 break;
467 case CODE_PROPS_RULE_ACTION:
468 self->code = translate_action (self, SC_RULE_ACTION);
469 break;
470 }
471}
472
473void
474code_scanner_last_string_free (void)
475{
476 STRING_FREE;
477}
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478
479void
480code_scanner_free (void)
481{
482 obstack_free (&obstack_for_string, 0);
483 /* Reclaim Flex's buffers. */
580b8926 484 yylex_destroy ();
e9071366 485}