source: trunk/texinfo/intl/plural.y@ 2828

Last change on this file since 2828 was 2617, checked in by bird, 20 years ago

GNU Texinfo 4.8
File size: 7.2 KB
Line 
1%{
2/* Expression parsing for plural form selection.
3 Copyright (C) 2000-2001, 2003 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 int yylex (YYSTYPE *lval, const char **pexp);
58static void yyerror (const char *str);
59
60/* Allocation of expressions. */
61
62static struct expression *
63new_exp (int nargs, enum operator op, struct expression * const *args)
64{
65 int i;
66 struct expression *newp;
67
68 /* If any of the argument could not be malloc'ed, just return NULL. */
69 for (i = nargs - 1; i >= 0; i--)
70 if (args[i] == NULL)
71 goto fail;
72
73 /* Allocate a new expression. */
74 newp = (struct expression *) malloc (sizeof (*newp));
75 if (newp != NULL)
76 {
77 newp->nargs = nargs;
78 newp->operation = op;
79 for (i = nargs - 1; i >= 0; i--)
80 newp->val.args[i] = args[i];
81 return newp;
82 }
83
84 fail:
85 for (i = nargs - 1; i >= 0; i--)
86 FREE_EXPRESSION (args[i]);
87
88 return NULL;
89}
90
91static inline struct expression *
92new_exp_0 (enum operator op)
93{
94 return new_exp (0, op, NULL);
95}
96
97static inline struct expression *
98new_exp_1 (enum operator op, struct expression *right)
99{
100 struct expression *args[1];
101
102 args[0] = right;
103 return new_exp (1, op, args);
104}
105
106static struct expression *
107new_exp_2 (enum operator op, struct expression *left, struct expression *right)
108{
109 struct expression *args[2];
110
111 args[0] = left;
112 args[1] = right;
113 return new_exp (2, op, args);
114}
115
116static inline struct expression *
117new_exp_3 (enum operator op, struct expression *bexp,
118 struct expression *tbranch, struct expression *fbranch)
119{
120 struct expression *args[3];
121
122 args[0] = bexp;
123 args[1] = tbranch;
124 args[2] = fbranch;
125 return new_exp (3, op, args);
126}
127
128%}
129
130/* This declares that all operators have the same associativity and the
131 precedence order as in C. See [Harbison, Steele: C, A Reference Manual].
132 There is no unary minus and no bitwise operators.
133 Operators with the same syntactic behaviour have been merged into a single
134 token, to save space in the array generated by bison. */
135%right '?' /* ? */
136%left '|' /* || */
137%left '&' /* && */
138%left EQUOP2 /* == != */
139%left CMPOP2 /* < > <= >= */
140%left ADDOP2 /* + - */
141%left MULOP2 /* * / % */
142%right '!' /* ! */
143
144%token <op> EQUOP2 CMPOP2 ADDOP2 MULOP2
145%token <num> NUMBER
146%type <exp> exp
147
148%%
149
150start: exp
151 {
152 if ($1 == NULL)
153 YYABORT;
154 ((struct parse_args *) arg)->res = $1;
155 }
156 ;
157
158exp: exp '?' exp ':' exp
159 {
160 $$ = new_exp_3 (qmop, $1, $3, $5);
161 }
162 | exp '|' exp
163 {
164 $$ = new_exp_2 (lor, $1, $3);
165 }
166 | exp '&' exp
167 {
168 $$ = new_exp_2 (land, $1, $3);
169 }
170 | exp EQUOP2 exp
171 {
172 $$ = new_exp_2 ($2, $1, $3);
173 }
174 | exp CMPOP2 exp
175 {
176 $$ = new_exp_2 ($2, $1, $3);
177 }
178 | exp ADDOP2 exp
179 {
180 $$ = new_exp_2 ($2, $1, $3);
181 }
182 | exp MULOP2 exp
183 {
184 $$ = new_exp_2 ($2, $1, $3);
185 }
186 | '!' exp
187 {
188 $$ = new_exp_1 (lnot, $2);
189 }
190 | 'n'
191 {
192 $$ = new_exp_0 (var);
193 }
194 | NUMBER
195 {
196 if (($$ = new_exp_0 (num)) != NULL)
197 $$->val.num = $1;
198 }
199 | '(' exp ')'
200 {
201 $$ = $2;
202 }
203 ;
204
205%%
206
207void
208internal_function
209FREE_EXPRESSION (struct expression *exp)
210{
211 if (exp == NULL)
212 return;
213
214 /* Handle the recursive case. */
215 switch (exp->nargs)
216 {
217 case 3:
218 FREE_EXPRESSION (exp->val.args[2]);
219 /* FALLTHROUGH */
220 case 2:
221 FREE_EXPRESSION (exp->val.args[1]);
222 /* FALLTHROUGH */
223 case 1:
224 FREE_EXPRESSION (exp->val.args[0]);
225 /* FALLTHROUGH */
226 default:
227 break;
228 }
229
230 free (exp);
231}
232
233
234static int
235yylex (YYSTYPE *lval, const char **pexp)
236{
237 const char *exp = *pexp;
238 int result;
239
240 while (1)
241 {
242 if (exp[0] == '\0')
243 {
244 *pexp = exp;
245 return YYEOF;
246 }
247
248 if (exp[0] != ' ' && exp[0] != '\t')
249 break;
250
251 ++exp;
252 }
253
254 result = *exp++;
255 switch (result)
256 {
257 case '0': case '1': case '2': case '3': case '4':
258 case '5': case '6': case '7': case '8': case '9':
259 {
260 unsigned long int n = result - '0';
261 while (exp[0] >= '0' && exp[0] <= '9')
262 {
263 n *= 10;
264 n += exp[0] - '0';
265 ++exp;
266 }
267 lval->num = n;
268 result = NUMBER;
269 }
270 break;
271
272 case '=':
273 if (exp[0] == '=')
274 {
275 ++exp;
276 lval->op = equal;
277 result = EQUOP2;
278 }
279 else
280 result = YYERRCODE;
281 break;
282
283 case '!':
284 if (exp[0] == '=')
285 {
286 ++exp;
287 lval->op = not_equal;
288 result = EQUOP2;
289 }
290 break;
291
292 case '&':
293 case '|':
294 if (exp[0] == result)
295 ++exp;
296 else
297 result = YYERRCODE;
298 break;
299
300 case '<':
301 if (exp[0] == '=')
302 {
303 ++exp;
304 lval->op = less_or_equal;
305 }
306 else
307 lval->op = less_than;
308 result = CMPOP2;
309 break;
310
311 case '>':
312 if (exp[0] == '=')
313 {
314 ++exp;
315 lval->op = greater_or_equal;
316 }
317 else
318 lval->op = greater_than;
319 result = CMPOP2;
320 break;
321
322 case '*':
323 lval->op = mult;
324 result = MULOP2;
325 break;
326
327 case '/':
328 lval->op = divide;
329 result = MULOP2;
330 break;
331
332 case '%':
333 lval->op = module;
334 result = MULOP2;
335 break;
336
337 case '+':
338 lval->op = plus;
339 result = ADDOP2;
340 break;
341
342 case '-':
343 lval->op = minus;
344 result = ADDOP2;
345 break;
346
347 case 'n':
348 case '?':
349 case ':':
350 case '(':
351 case ')':
352 /* Nothing, just return the character. */
353 break;
354
355 case ';':
356 case '\n':
357 case '\0':
358 /* Be safe and let the user call this function again. */
359 --exp;
360 result = YYEOF;
361 break;
362
363 default:
364 result = YYERRCODE;
365#if YYDEBUG != 0
366 --exp;
367#endif
368 break;
369 }
370
371 *pexp = exp;
372
373 return result;
374}
375
376
377static void
378yyerror (const char *str)
379{
380 /* Do nothing. We don't print error messages here. */
381}
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