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1/* Bison Action Scanner -*- C -*-
2
3 Copyright (C) 2006 Free Software Foundation, Inc.
4
5 This file is part of Bison, the GNU Compiler Compiler.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
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
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 02110-1301 USA
21*/
22
23%option debug nodefault nounput noyywrap never-interactive
24%option prefix="code_" outfile="lex.yy.c"
25
26%{
27/* Work around a bug in flex 2.5.31. See Debian bug 333231
28 <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=333231>. */
29#undef code_wrap
30#define code_wrap() 1
31
32#define FLEX_PREFIX(Id) code_ ## Id
33#include "flex-scanner.h"
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34
35#include "complain.h"
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36#include "reader.h"
37#include "getargs.h"
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38#include <get-errno.h>
39#include <quote.h>
40
41#include "scan-code.h"
42
43/* The current calling start condition: SC_RULE_ACTION or
44 SC_SYMBOL_ACTION. */
b0f4c4ea 45# define YY_DECL char *code_lex (int sc_context, symbol_list *rule)
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46YY_DECL;
47
48#define YY_USER_ACTION location_compute (loc, &loc->end, yytext, yyleng);
49
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50static void handle_action_dollar (symbol_list *rule, char *cp,
51 location dollar_loc);
52static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
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53static location the_location;
54static location *loc = &the_location;
ddc8ede1
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55
56/* True if an untyped $$ or $n was seen. */
57static bool untyped_var_seen;
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58%}
59 /* C and C++ comments in code. */
60%x SC_COMMENT SC_LINE_COMMENT
61 /* Strings and characters in code. */
62%x SC_STRING SC_CHARACTER
63 /* Whether in a rule or symbol action. Specifies the translation
64 of $ and @. */
65%x SC_RULE_ACTION SC_SYMBOL_ACTION
66
67
68/* POSIX says that a tag must be both an id and a C union member, but
69 historically almost any character is allowed in a tag. We disallow
70 NUL and newline, as this simplifies our implementation. */
71tag [^\0\n>]+
72
73/* Zero or more instances of backslash-newline. Following GCC, allow
74 white space between the backslash and the newline. */
75splice (\\[ \f\t\v]*\n)*
76
77%%
78
79%{
2346344a 80 /* Nesting level of the current code in braces. */
4f82b42a 81 int braces_level = 0;
2346344a 82
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83 /* This scanner is special: it is invoked only once, henceforth
84 is expected to return only once. This initialization is
85 therefore done once per action to translate. */
4f82b42a
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86 aver (sc_context == SC_SYMBOL_ACTION
87 || sc_context == SC_RULE_ACTION
88 || sc_context == INITIAL);
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89 BEGIN sc_context;
90%}
91
92 /*------------------------------------------------------------.
93 | Scanning a C comment. The initial `/ *' is already eaten. |
94 `------------------------------------------------------------*/
95
96<SC_COMMENT>
97{
98 "*"{splice}"/" STRING_GROW; BEGIN sc_context;
99}
100
101
102 /*--------------------------------------------------------------.
103 | Scanning a line comment. The initial `//' is already eaten. |
104 `--------------------------------------------------------------*/
105
106<SC_LINE_COMMENT>
107{
108 "\n" STRING_GROW; BEGIN sc_context;
109 {splice} STRING_GROW;
110}
111
112
113 /*--------------------------------------------.
114 | Scanning user-code characters and strings. |
115 `--------------------------------------------*/
116
117<SC_CHARACTER,SC_STRING>
118{
119 {splice}|\\{splice}. STRING_GROW;
120}
121
122<SC_CHARACTER>
123{
124 "'" STRING_GROW; BEGIN sc_context;
125}
126
127<SC_STRING>
128{
129 "\"" STRING_GROW; BEGIN sc_context;
130}
131
132
133<SC_RULE_ACTION,SC_SYMBOL_ACTION>{
134 "'" {
135 STRING_GROW;
136 BEGIN SC_CHARACTER;
137 }
138 "\"" {
139 STRING_GROW;
140 BEGIN SC_STRING;
141 }
142 "/"{splice}"*" {
143 STRING_GROW;
144 BEGIN SC_COMMENT;
145 }
146 "/"{splice}"/" {
147 STRING_GROW;
148 BEGIN SC_LINE_COMMENT;
149 }
150}
151
152<SC_RULE_ACTION>
153{
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154 "$"("<"{tag}">")?(-?[0-9]+|"$") handle_action_dollar (rule, yytext, *loc);
155 "@"(-?[0-9]+|"$") handle_action_at (rule, yytext, *loc);
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156
157 "$" {
158 warn_at (*loc, _("stray `$'"));
159 obstack_sgrow (&obstack_for_string, "$][");
160 }
161 "@" {
162 warn_at (*loc, _("stray `@'"));
163 obstack_sgrow (&obstack_for_string, "@@");
164 }
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165
166 "{" STRING_GROW; ++braces_level;
167 "}" {
168 bool outer_brace = --braces_level < 0;
169
170 /* As an undocumented Bison extension, append `;' before the last
171 brace in braced code, so that the user code can omit trailing
172 `;'. But do not append `;' if emulating Yacc, since Yacc does
173 not append one.
174
175 FIXME: Bison should warn if a semicolon seems to be necessary
176 here, and should omit the semicolon if it seems unnecessary
177 (e.g., after ';', '{', or '}', each followed by comments or
178 white space). Such a warning shouldn't depend on --yacc; it
179 should depend on a new --pedantic option, which would cause
180 Bison to warn if it detects an extension to POSIX. --pedantic
181 should also diagnose other Bison extensions like %yacc.
182 Perhaps there should also be a GCC-style --pedantic-errors
183 option, so that such warnings are diagnosed as errors. */
184 if (outer_brace && ! yacc_flag)
185 obstack_1grow (&obstack_for_string, ';');
186
187 STRING_GROW;
188 }
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189}
190
191<SC_SYMBOL_ACTION>
192{
b0f4c4ea 193 "$$" obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar[");
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194 "@$" obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
195}
196
197
198 /*-----------------------------------------.
199 | Escape M4 quoting characters in C code. |
200 `-----------------------------------------*/
201
202<*>
203{
204 \$ obstack_sgrow (&obstack_for_string, "$][");
205 \@ obstack_sgrow (&obstack_for_string, "@@");
206 \[ obstack_sgrow (&obstack_for_string, "@{");
207 \] obstack_sgrow (&obstack_for_string, "@}");
208}
209
210 /*-----------------------------------------------------.
211 | By default, grow the string obstack with the input. |
212 `-----------------------------------------------------*/
213
214<*>.|\n STRING_GROW;
215
216 /* End of processing. */
217<*><<EOF>> {
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218 obstack_1grow (&obstack_for_string, '\0');
219 return obstack_finish (&obstack_for_string);
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220 }
221
222%%
223
224/* Keeps track of the maximum number of semantic values to the left of
225 a handle (those referenced by $0, $-1, etc.) are required by the
226 semantic actions of this grammar. */
227int max_left_semantic_context = 0;
228
229
230/*------------------------------------------------------------------.
231| TEXT is pointing to a wannabee semantic value (i.e., a `$'). |
232| |
233| Possible inputs: $[<TYPENAME>]($|integer) |
234| |
235| Output to OBSTACK_FOR_STRING a reference to this semantic value. |
236`------------------------------------------------------------------*/
237
238static void
4210cd0b 239handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
e9071366 240{
b0f4c4ea 241 const char *type_name = NULL;
e9071366 242 char *cp = text + 1;
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243 symbol_list *effective_rule;
244 int effective_rule_length;
245
246 if (rule->midrule_parent_rule)
247 {
248 effective_rule = rule->midrule_parent_rule;
249 effective_rule_length = rule->midrule_parent_rhs_index - 1;
250 }
251 else
252 {
253 effective_rule = rule;
254 effective_rule_length = symbol_list_length (rule->next);
255 }
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256
257 /* Get the type name if explicit. */
258 if (*cp == '<')
259 {
260 type_name = ++cp;
261 while (*cp != '>')
262 ++cp;
263 *cp = '\0';
264 ++cp;
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265 if (untyped_var_seen)
266 complain_at (dollar_loc, _("explicit type given in untyped grammar"));
267 tag_seen = true;
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268 }
269
270 if (*cp == '$')
271 {
272 if (!type_name)
4210cd0b 273 type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
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274
275 if (!type_name)
ad6b1efa 276 {
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277 if (union_seen | tag_seen)
278 {
279 if (rule->midrule_parent_rule)
280 complain_at (dollar_loc,
281 _("$$ for the midrule at $%d of `%s'"
282 " has no declared type"),
283 rule->midrule_parent_rhs_index,
3be03b13 284 effective_rule->content.sym->tag);
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285 else
286 complain_at (dollar_loc, _("$$ of `%s' has no declared type"),
3be03b13 287 rule->content.sym->tag);
ddc8ede1 288 }
ad6b1efa 289 else
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290 untyped_var_seen = true;
291 type_name = "";
ad6b1efa 292 }
ddc8ede1 293
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294 obstack_fgrow1 (&obstack_for_string,
295 "]b4_lhs_value([%s])[", type_name);
b0f4c4ea 296 rule->used = true;
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297 }
298 else
299 {
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300 long int num = strtol (cp, NULL, 10);
301
302 if (1 - INT_MAX + effective_rule_length <= num
303 && num <= effective_rule_length)
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304 {
305 int n = num;
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306 if (max_left_semantic_context < 1 - n)
307 max_left_semantic_context = 1 - n;
308 if (!type_name && 0 < n)
0c8e079f 309 type_name =
ffa4ba3a 310 symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
e9071366 311 if (!type_name)
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312 {
313 if (union_seen | tag_seen)
314 complain_at (dollar_loc, _("$%d of `%s' has no declared type"),
3be03b13 315 n, effective_rule->content.sym->tag);
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316 else
317 untyped_var_seen = true;
318 type_name = "";
319 }
320
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321 obstack_fgrow3 (&obstack_for_string,
322 "]b4_rhs_value(%d, %d, [%s])[",
ffa4ba3a 323 effective_rule_length, n, type_name);
b0f4c4ea 324 symbol_list_n_used_set (effective_rule, n, true);
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325 }
326 else
0c8e079f 327 complain_at (dollar_loc, _("integer out of range: %s"), quote (text));
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328 }
329}
330
331
332/*------------------------------------------------------.
333| TEXT is a location token (i.e., a `@...'). Output to |
334| OBSTACK_FOR_STRING a reference to this location. |
335`------------------------------------------------------*/
336
337static void
4210cd0b 338handle_action_at (symbol_list *rule, char *text, location at_loc)
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339{
340 char *cp = text + 1;
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341 int effective_rule_length =
342 (rule->midrule_parent_rule
343 ? rule->midrule_parent_rhs_index - 1
344 : symbol_list_length (rule->next));
ffa4ba3a 345
4f82b42a 346 locations_flag = true;
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347
348 if (*cp == '$')
349 obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
350 else
351 {
ddc8ede1 352 long int num = strtol (cp, NULL, 10);
e9071366 353
ddc8ede1
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354 if (1 - INT_MAX + effective_rule_length <= num
355 && num <= effective_rule_length)
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356 {
357 int n = num;
358 obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
ffa4ba3a 359 effective_rule_length, n);
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360 }
361 else
0c8e079f 362 complain_at (at_loc, _("integer out of range: %s"), quote (text));
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363 }
364}
365
366
367/*-------------------------.
368| Initialize the scanner. |
369`-------------------------*/
370
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371/* Translate the dollars and ats in \a a, whose location is \a l. The
372 translation is for \a rule, in the context \a sc_context
ddc8ede1 373 (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL). */
e9071366 374
eb095650 375static char const *
b0f4c4ea 376translate_action (int sc_context, symbol_list *rule, char const *a, location l)
e9071366 377{
2ce4ed68 378 char *res;
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379 static bool initialized = false;
380 if (!initialized)
381 {
382 obstack_init (&obstack_for_string);
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383 yy_flex_debug = 0;
384 initialized = true;
385 }
386
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387 loc->start = loc->end = l.start;
388 yy_switch_to_buffer (yy_scan_string (a));
389 res = code_lex (sc_context, rule);
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390 yy_delete_buffer (YY_CURRENT_BUFFER);
391
392 return res;
393}
394
eb095650 395char const *
b0f4c4ea 396translate_rule_action (symbol_list *rule)
76290368 397{
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398 return translate_action (SC_RULE_ACTION, rule, rule->action,
399 rule->action_location);
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400}
401
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402char const *
403translate_symbol_action (char const *a, location l)
76290368 404{
b0f4c4ea 405 return translate_action (SC_SYMBOL_ACTION, NULL, a, l);
76290368
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406}
407
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408char const *
409translate_code (char const *a, location l)
e9071366 410{
b0f4c4ea 411 return translate_action (INITIAL, NULL, a, l);
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412}
413
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414/*-----------------------------------------------.
415| Free all the memory allocated to the scanner. |
416`-----------------------------------------------*/
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417
418void
419code_scanner_free (void)
420{
421 obstack_free (&obstack_for_string, 0);
422 /* Reclaim Flex's buffers. */
580b8926 423 yylex_destroy ();
e9071366 424}