intl/plural.y

   1 %{
   2 /* Expression parsing for plural form selection.
   3    Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Written by Ulrich Drepper <drepper@cygnus.com>, 2000.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library 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 GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 /* The bison generated parser uses alloca.  AIX 3 forces us to put this
  23    declaration at the beginning of the file.  The declaration in bison's
  24    skeleton file comes too late.  This must come before <config.h>
  25    because <config.h> may include arbitrary system headers.  */
  26 #if defined _AIX && !defined __GNUC__
  27  #pragma alloca
  28 #endif
  29 #ifdef HAVE_CONFIG_H
  30 # include <config.h>
  31 #endif
  32
  33 #include <stddef.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include "plural-exp.h"
  37
  38 /* The main function generated by the parser is called __gettextparse,
  39    but we want it to be called PLURAL_PARSE.  */
  40 #ifndef _LIBC
  41 # define __gettextparse PLURAL_PARSE
  42 #endif
  43
  44 #define YYLEX_PARAM     &((struct parse_args *) arg)->cp
  45 #define YYPARSE_PARAM   arg
  46 %}
  47 %pure_parser
  48 %expect 7
  49
  50 %union {
  51   unsigned long int num;
  52   enum operator op;
  53   struct expression *exp;
  54 }
  55
  56 %{
  57 /* Prototypes for local functions.  */
  58 static struct expression *new_exp PARAMS ((int nargs, enum operator op,
  59                                            struct expression * const *args));
  60 static inline struct expression *new_exp_0 PARAMS ((enum operator op));
  61 static inline struct expression *new_exp_1 PARAMS ((enum operator op,
  62                                                    struct expression *right));
  63 static struct expression *new_exp_2 PARAMS ((enum operator op,
  64                                              struct expression *left,
  65                                              struct expression *right));
  66 static inline struct expression *new_exp_3 PARAMS ((enum operator op,
  67                                                    struct expression *bexp,
  68                                                    struct expression *tbranch,
  69                                                    struct expression *fbranch));
  70 static int yylex PARAMS ((YYSTYPE *lval, const char **pexp));
  71 static void yyerror PARAMS ((const char *str));
  72
  73 /* Allocation of expressions.  */
  74
  75 static struct expression *
  76 new_exp (nargs, op, args)
  77      int nargs;
  78      enum operator op;
  79      struct expression * const *args;
  80 {
  81   int i;
  82   struct expression *newp;
  83
  84   /* If any of the argument could not be malloc'ed, just return NULL.  */
  85   for (i = nargs - 1; i >= 0; i--)
  86     if (args[i] == NULL)
  87       goto fail;
  88
  89   /* Allocate a new expression.  */
  90   newp = (struct expression *) malloc (sizeof (*newp));
  91   if (newp != NULL)
  92     {
  93       newp->nargs = nargs;
  94       newp->operation = op;
  95       for (i = nargs - 1; i >= 0; i--)
  96         newp->val.args[i] = args[i];
  97       return newp;
  98     }
  99
 100  fail:
 101   for (i = nargs - 1; i >= 0; i--)
 102     FREE_EXPRESSION (args[i]);
 103
 104   return NULL;
 105 }
 106
 107 static inline struct expression *
 108 new_exp_0 (op)
 109      enum operator op;
 110 {
 111   return new_exp (0, op, NULL);
 112 }
 113
 114 static inline struct expression *
 115 new_exp_1 (op, right)
 116      enum operator op;
 117      struct expression *right;
 118 {
 119   struct expression *args[1];
 120
 121   args[0] = right;
 122   return new_exp (1, op, args);
 123 }
 124
 125 static struct expression *
 126 new_exp_2 (op, left, right)
 127      enum operator op;
 128      struct expression *left;
 129      struct expression *right;
 130 {
 131   struct expression *args[2];
 132
 133   args[0] = left;
 134   args[1] = right;
 135   return new_exp (2, op, args);
 136 }
 137
 138 static inline struct expression *
 139 new_exp_3 (op, bexp, tbranch, fbranch)
 140      enum operator op;
 141      struct expression *bexp;
 142      struct expression *tbranch;
 143      struct expression *fbranch;
 144 {
 145   struct expression *args[3];
 146
 147   args[0] = bexp;
 148   args[1] = tbranch;
 149   args[2] = fbranch;
 150   return new_exp (3, op, args);
 151 }
 152
 153 %}
 154
 155 /* This declares that all operators have the same associativity and the
 156    precedence order as in C.  See [Harbison, Steele: C, A Reference Manual].
 157    There is no unary minus and no bitwise operators.
 158    Operators with the same syntactic behaviour have been merged into a single
 159    token, to save space in the array generated by bison.  */
 160 %right '?'              /*   ?          */
 161 %left '|'               /*   ||         */
 162 %left '&'               /*   &&         */
 163 %left EQUOP2            /*   == !=      */
 164 %left CMPOP2            /*   < > <= >=  */
 165 %left ADDOP2            /*   + -        */
 166 %left MULOP2            /*   * / %      */
 167 %right '!'              /*   !          */
 168
 169 %token <op> EQUOP2 CMPOP2 ADDOP2 MULOP2
 170 %token <num> NUMBER
 171 %type <exp> exp
 172
 173 %%
 174
 175 start:    exp
 176           {
 177             if ($1 == NULL)
 178               YYABORT;
 179             ((struct parse_args *) arg)->res = $1;
 180           }
 181         ;
 182
 183 exp:      exp '?' exp ':' exp
 184           {
 185             $$ = new_exp_3 (qmop, $1, $3, $5);
 186           }
 187         | exp '|' exp
 188           {
 189             $$ = new_exp_2 (lor, $1, $3);
 190           }
 191         | exp '&' exp
 192           {
 193             $$ = new_exp_2 (land, $1, $3);
 194           }
 195         | exp EQUOP2 exp
 196           {
 197             $$ = new_exp_2 ($2, $1, $3);
 198           }
 199         | exp CMPOP2 exp
 200           {
 201             $$ = new_exp_2 ($2, $1, $3);
 202           }
 203         | exp ADDOP2 exp
 204           {
 205             $$ = new_exp_2 ($2, $1, $3);
 206           }
 207         | exp MULOP2 exp
 208           {
 209             $$ = new_exp_2 ($2, $1, $3);
 210           }
 211         | '!' exp
 212           {
 213             $$ = new_exp_1 (lnot, $2);
 214           }
 215         | 'n'
 216           {
 217             $$ = new_exp_0 (var);
 218           }
 219         | NUMBER
 220           {
 221             if (($$ = new_exp_0 (num)) != NULL)
 222               $$->val.num = $1;
 223           }
 224         | '(' exp ')'
 225           {
 226             $$ = $2;
 227           }
 228         ;
 229
 230 %%
 231
 232 void
 233 internal_function
 234 FREE_EXPRESSION (exp)
 235      struct expression *exp;
 236 {
 237   if (exp == NULL)
 238     return;
 239
 240   /* Handle the recursive case.  */
 241   switch (exp->nargs)
 242     {
 243     case 3:
 244       FREE_EXPRESSION (exp->val.args[2]);
 245       /* FALLTHROUGH */
 246     case 2:
 247       FREE_EXPRESSION (exp->val.args[1]);
 248       /* FALLTHROUGH */
 249     case 1:
 250       FREE_EXPRESSION (exp->val.args[0]);
 251       /* FALLTHROUGH */
 252     default:
 253       break;
 254     }
 255
 256   free (exp);
 257 }
 258
 259
 260 static int
 261 yylex (lval, pexp)
 262      YYSTYPE *lval;
 263      const char **pexp;
 264 {
 265   const char *exp = *pexp;
 266   int result;
 267
 268   while (1)
 269     {
 270       if (exp[0] == '\0')
 271         {
 272           *pexp = exp;
 273           return YYEOF;
 274         }
 275
 276       if (exp[0] != ' ' && exp[0] != '\t')
 277         break;
 278
 279       ++exp;
 280     }
 281
 282   result = *exp++;
 283   switch (result)
 284     {
 285     case '0': case '1': case '2': case '3': case '4':
 286     case '5': case '6': case '7': case '8': case '9':
 287       {
 288         unsigned long int n = result - '0';
 289         while (exp[0] >= '0' && exp[0] <= '9')
 290           {
 291             n *= 10;
 292             n += exp[0] - '0';
 293             ++exp;
 294           }
 295         lval->num = n;
 296         result = NUMBER;
 297       }
 298       break;
 299
 300     case '=':
 301       if (exp[0] == '=')
 302         {
 303           ++exp;
 304           lval->op = equal;
 305           result = EQUOP2;
 306         }
 307       else
 308         result = YYERRCODE;
 309       break;
 310
 311     case '!':
 312       if (exp[0] == '=')
 313         {
 314           ++exp;
 315           lval->op = not_equal;
 316           result = EQUOP2;
 317         }
 318       break;
 319
 320     case '&':
 321     case '|':
 322       if (exp[0] == result)
 323         ++exp;
 324       else
 325         result = YYERRCODE;
 326       break;
 327
 328     case '<':
 329       if (exp[0] == '=')
 330         {
 331           ++exp;
 332           lval->op = less_or_equal;
 333         }
 334       else
 335         lval->op = less_than;
 336       result = CMPOP2;
 337       break;
 338
 339     case '>':
 340       if (exp[0] == '=')
 341         {
 342           ++exp;
 343           lval->op = greater_or_equal;
 344         }
 345       else
 346         lval->op = greater_than;
 347       result = CMPOP2;
 348       break;
 349
 350     case '*':
 351       lval->op = mult;
 352       result = MULOP2;
 353       break;
 354
 355     case '/':
 356       lval->op = divide;
 357       result = MULOP2;
 358       break;
 359
 360     case '%':
 361       lval->op = module;
 362       result = MULOP2;
 363       break;
 364
 365     case '+':
 366       lval->op = plus;
 367       result = ADDOP2;
 368       break;
 369
 370     case '-':
 371       lval->op = minus;
 372       result = ADDOP2;
 373       break;
 374
 375     case 'n':
 376     case '?':
 377     case ':':
 378     case '(':
 379     case ')':
 380       /* Nothing, just return the character.  */
 381       break;
 382
 383     case ';':
 384     case '\n':
 385     case '\0':
 386       /* Be safe and let the user call this function again.  */
 387       --exp;
 388       result = YYEOF;
 389       break;
 390
 391     default:
 392       result = YYERRCODE;
 393 #if YYDEBUG != 0
 394       --exp;
 395 #endif
 396       break;
 397     }
 398
 399   *pexp = exp;
 400
 401   return result;
 402 }
 403
 404
 405 static void
 406 yyerror (str)
 407      const char *str;
 408 {
 409   /* Do nothing.  We don't print error messages here.  */
 410 }