source: trunk/grep/intl/plural.y@ 2705

Last change on this file since 2705 was 2557, checked in by bird, 20 years ago

grep 2.5.1a
File size: 8.0 KB
Line 
1%{
2/* Expression parsing for plural form selection.
3 Copyright (C) 2000, 2001 Free Software Foundation, Inc.
4 Written by Ulrich Drepper <drepper@cygnus.com>, 2000.
5
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Library General Public License as published
8 by the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Library General Public License for more details.
15
16 You should have received a copy of the GNU Library General Public
17 License along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
19 USA. */
20
21/* The bison generated parser uses alloca. AIX 3 forces us to put this
22 declaration at the beginning of the file. The declaration in bison's
23 skeleton file comes too late. This must come before <config.h>
24 because <config.h> may include arbitrary system headers. */
25#if defined _AIX && !defined __GNUC__
26 #pragma alloca
27#endif
28
29#ifdef HAVE_CONFIG_H
30# include <config.h>
31#endif
32
33#include <stddef.h>
34#include <stdlib.h>
35#include "plural-exp.h"
36
37/* The main function generated by the parser is called __gettextparse,
38 but we want it to be called PLURAL_PARSE. */
39#ifndef _LIBC
40# define __gettextparse PLURAL_PARSE
41#endif
42
43#define YYLEX_PARAM &((struct parse_args *) arg)->cp
44#define YYPARSE_PARAM arg
45%}
46%pure_parser
47%expect 7
48
49%union {
50 unsigned long int num;
51 enum operator op;
52 struct expression *exp;
53}
54
55%{
56/* Prototypes for local functions. */
57static struct expression *new_exp PARAMS ((int nargs, enum operator op,
58 struct expression * const *args));
59static inline struct expression *new_exp_0 PARAMS ((enum operator op));
60static inline struct expression *new_exp_1 PARAMS ((enum operator op,
61 struct expression *right));
62static struct expression *new_exp_2 PARAMS ((enum operator op,
63 struct expression *left,
64 struct expression *right));
65static inline struct expression *new_exp_3 PARAMS ((enum operator op,
66 struct expression *bexp,
67 struct expression *tbranch,
68 struct expression *fbranch));
69static int yylex PARAMS ((YYSTYPE *lval, const char **pexp));
70static void yyerror PARAMS ((const char *str));
71
72/* Allocation of expressions. */
73
74static struct expression *
75new_exp (nargs, op, args)
76 int nargs;
77 enum operator op;
78 struct expression * const *args;
79{
80 int i;
81 struct expression *newp;
82
83 /* If any of the argument could not be malloc'ed, just return NULL. */
84 for (i = nargs - 1; i >= 0; i--)
85 if (args[i] == NULL)
86 goto fail;
87
88 /* Allocate a new expression. */
89 newp = (struct expression *) malloc (sizeof (*newp));
90 if (newp != NULL)
91 {
92 newp->nargs = nargs;
93 newp->operation = op;
94 for (i = nargs - 1; i >= 0; i--)
95 newp->val.args[i] = args[i];
96 return newp;
97 }
98
99 fail:
100 for (i = nargs - 1; i >= 0; i--)
101 FREE_EXPRESSION (args[i]);
102
103 return NULL;
104}
105
106static inline struct expression *
107new_exp_0 (op)
108 enum operator op;
109{
110 return new_exp (0, op, NULL);
111}
112
113static inline struct expression *
114new_exp_1 (op, right)
115 enum operator op;
116 struct expression *right;
117{
118 struct expression *args[1];
119
120 args[0] = right;
121 return new_exp (1, op, args);
122}
123
124static struct expression *
125new_exp_2 (op, left, right)
126 enum operator op;
127 struct expression *left;
128 struct expression *right;
129{
130 struct expression *args[2];
131
132 args[0] = left;
133 args[1] = right;
134 return new_exp (2, op, args);
135}
136
137static inline struct expression *
138new_exp_3 (op, bexp, tbranch, fbranch)
139 enum operator op;
140 struct expression *bexp;
141 struct expression *tbranch;
142 struct expression *fbranch;
143{
144 struct expression *args[3];
145
146 args[0] = bexp;
147 args[1] = tbranch;
148 args[2] = fbranch;
149 return new_exp (3, op, args);
150}
151
152%}
153
154/* This declares that all operators have the same associativity and the
155 precedence order as in C. See [Harbison, Steele: C, A Reference Manual].
156 There is no unary minus and no bitwise operators.
157 Operators with the same syntactic behaviour have been merged into a single
158 token, to save space in the array generated by bison. */
159%right '?' /* ? */
160%left '|' /* || */
161%left '&' /* && */
162%left EQUOP2 /* == != */
163%left CMPOP2 /* < > <= >= */
164%left ADDOP2 /* + - */
165%left MULOP2 /* * / % */
166%right '!' /* ! */
167
168%token <op> EQUOP2 CMPOP2 ADDOP2 MULOP2
169%token <num> NUMBER
170%type <exp> exp
171
172%%
173
174start: exp
175 {
176 if ($1 == NULL)
177 YYABORT;
178 ((struct parse_args *) arg)->res = $1;
179 }
180 ;
181
182exp: exp '?' exp ':' exp
183 {
184 $$ = new_exp_3 (qmop, $1, $3, $5);
185 }
186 | exp '|' exp
187 {
188 $$ = new_exp_2 (lor, $1, $3);
189 }
190 | exp '&' exp
191 {
192 $$ = new_exp_2 (land, $1, $3);
193 }
194 | exp EQUOP2 exp
195 {
196 $$ = new_exp_2 ($2, $1, $3);
197 }
198 | exp CMPOP2 exp
199 {
200 $$ = new_exp_2 ($2, $1, $3);
201 }
202 | exp ADDOP2 exp
203 {
204 $$ = new_exp_2 ($2, $1, $3);
205 }
206 | exp MULOP2 exp
207 {
208 $$ = new_exp_2 ($2, $1, $3);
209 }
210 | '!' exp
211 {
212 $$ = new_exp_1 (lnot, $2);
213 }
214 | 'n'
215 {
216 $$ = new_exp_0 (var);
217 }
218 | NUMBER
219 {
220 if (($$ = new_exp_0 (num)) != NULL)
221 $$->val.num = $1;
222 }
223 | '(' exp ')'
224 {
225 $$ = $2;
226 }
227 ;
228
229%%
230
231void
232internal_function
233FREE_EXPRESSION (exp)
234 struct expression *exp;
235{
236 if (exp == NULL)
237 return;
238
239 /* Handle the recursive case. */
240 switch (exp->nargs)
241 {
242 case 3:
243 FREE_EXPRESSION (exp->val.args[2]);
244 /* FALLTHROUGH */
245 case 2:
246 FREE_EXPRESSION (exp->val.args[1]);
247 /* FALLTHROUGH */
248 case 1:
249 FREE_EXPRESSION (exp->val.args[0]);
250 /* FALLTHROUGH */
251 default:
252 break;
253 }
254
255 free (exp);
256}
257
258
259static int
260yylex (lval, pexp)
261 YYSTYPE *lval;
262 const char **pexp;
263{
264 const char *exp = *pexp;
265 int result;
266
267 while (1)
268 {
269 if (exp[0] == '\0')
270 {
271 *pexp = exp;
272 return YYEOF;
273 }
274
275 if (exp[0] != ' ' && exp[0] != '\t')
276 break;
277
278 ++exp;
279 }
280
281 result = *exp++;
282 switch (result)
283 {
284 case '0': case '1': case '2': case '3': case '4':
285 case '5': case '6': case '7': case '8': case '9':
286 {
287 unsigned long int n = result - '0';
288 while (exp[0] >= '0' && exp[0] <= '9')
289 {
290 n *= 10;
291 n += exp[0] - '0';
292 ++exp;
293 }
294 lval->num = n;
295 result = NUMBER;
296 }
297 break;
298
299 case '=':
300 if (exp[0] == '=')
301 {
302 ++exp;
303 lval->op = equal;
304 result = EQUOP2;
305 }
306 else
307 result = YYERRCODE;
308 break;
309
310 case '!':
311 if (exp[0] == '=')
312 {
313 ++exp;
314 lval->op = not_equal;
315 result = EQUOP2;
316 }
317 break;
318
319 case '&':
320 case '|':
321 if (exp[0] == result)
322 ++exp;
323 else
324 result = YYERRCODE;
325 break;
326
327 case '<':
328 if (exp[0] == '=')
329 {
330 ++exp;
331 lval->op = less_or_equal;
332 }
333 else
334 lval->op = less_than;
335 result = CMPOP2;
336 break;
337
338 case '>':
339 if (exp[0] == '=')
340 {
341 ++exp;
342 lval->op = greater_or_equal;
343 }
344 else
345 lval->op = greater_than;
346 result = CMPOP2;
347 break;
348
349 case '*':
350 lval->op = mult;
351 result = MULOP2;
352 break;
353
354 case '/':
355 lval->op = divide;
356 result = MULOP2;
357 break;
358
359 case '%':
360 lval->op = module;
361 result = MULOP2;
362 break;
363
364 case '+':
365 lval->op = plus;
366 result = ADDOP2;
367 break;
368
369 case '-':
370 lval->op = minus;
371 result = ADDOP2;
372 break;
373
374 case 'n':
375 case '?':
376 case ':':
377 case '(':
378 case ')':
379 /* Nothing, just return the character. */
380 break;
381
382 case ';':
383 case '\n':
384 case '\0':
385 /* Be safe and let the user call this function again. */
386 --exp;
387 result = YYEOF;
388 break;
389
390 default:
391 result = YYERRCODE;
392#if YYDEBUG != 0
393 --exp;
394#endif
395 break;
396 }
397
398 *pexp = exp;
399
400 return result;
401}
402
403
404static void
405yyerror (str)
406 const char *str;
407{
408 /* Do nothing. We don't print error messages here. */
409}
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