lib/intl/plural.y

   1 %{
   2 /* plural.y - Expression parsing for plural form selection. */
   3
   4 /* Copyright (C) 2000, 2001, 2005-2009 Free Software Foundation, Inc.
   5    Written by Ulrich Drepper <drepper@cygnus.com>, 2000.
   6
   7    This file is part of GNU Bush.
   8
   9    Bush is free software: you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation, either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    Bush is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bush.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 /* The bison generated parser uses alloca.  AIX 3 forces us to put this
  24    declaration at the beginning of the file.  The declaration in bison's
  25    skeleton file comes too late.  This must come before <config.h>
  26    because <config.h> may include arbitrary system headers.  */
  27 #if defined _AIX && !defined __GNUC__
  28  #pragma alloca
  29 #endif
  30
  31 #ifdef HAVE_CONFIG_H
  32 # include <config.h>
  33 #endif
  34
  35 #include <stddef.h>
  36 #include <stdlib.h>
  37 #include "plural-exp.h"
  38
  39 /* The main function generated by the parser is called __gettextparse,
  40    but we want it to be called PLURAL_PARSE.  */
  41 #ifndef _LIBC
  42 # define __gettextparse PLURAL_PARSE
  43 #endif
  44
  45 #define YYLEX_PARAM     &((struct parse_args *) arg)->cp
  46 #define YYPARSE_PARAM   arg
  47 %}
  48 %pure_parser
  49 %expect 7
  50
  51 %union {
  52   unsigned long int num;
  53   enum operator op;
  54   struct expression *exp;
  55 }
  56
  57 %{
  58 /* Prototypes for local functions.  */
  59 static struct expression *new_exp PARAMS ((int nargs, enum operator op,
  60                                            struct expression * const *args));
  61 static inline struct expression *new_exp_0 PARAMS ((enum operator op));
  62 static inline struct expression *new_exp_1 PARAMS ((enum operator op,
  63                                                    struct expression *right));
  64 static struct expression *new_exp_2 PARAMS ((enum operator op,
  65                                              struct expression *left,
  66                                              struct expression *right));
  67 static inline struct expression *new_exp_3 PARAMS ((enum operator op,
  68                                                    struct expression *bexp,
  69                                                    struct expression *tbranch,
  70                                                    struct expression *fbranch));
  71 static int yylex PARAMS ((YYSTYPE *lval, const char **pexp));
  72 static void yyerror PARAMS ((const char *str));
  73
  74 /* Allocation of expressions.  */
  75
  76 static struct expression *
  77 new_exp (nargs, op, args)
  78      int nargs;
  79      enum operator op;
  80      struct expression * const *args;
  81 {
  82   int i;
  83   struct expression *newp;
  84
  85   /* If any of the argument could not be malloc'ed, just return NULL.  */
  86   for (i = nargs - 1; i >= 0; i--)
  87     if (args[i] == NULL)
  88       goto fail;
  89
  90   /* Allocate a new expression.  */
  91   newp = (struct expression *) malloc (sizeof (*newp));
  92   if (newp != NULL)
  93     {
  94       newp->nargs = nargs;
  95       newp->operation = op;
  96       for (i = nargs - 1; i >= 0; i--)
  97         newp->val.args[i] = args[i];
  98       return newp;
  99     }
 100
 101  fail:
 102   for (i = nargs - 1; i >= 0; i--)
 103     FREE_EXPRESSION (args[i]);
 104
 105   return NULL;
 106 }
 107
 108 static inline struct expression *
 109 new_exp_0 (op)
 110      enum operator op;
 111 {
 112   return new_exp (0, op, NULL);
 113 }
 114
 115 static inline struct expression *
 116 new_exp_1 (op, right)
 117      enum operator op;
 118      struct expression *right;
 119 {
 120   struct expression *args[1];
 121
 122   args[0] = right;
 123   return new_exp (1, op, args);
 124 }
 125
 126 static struct expression *
 127 new_exp_2 (op, left, right)
 128      enum operator op;
 129      struct expression *left;
 130      struct expression *right;
 131 {
 132   struct expression *args[2];
 133
 134   args[0] = left;
 135   args[1] = right;
 136   return new_exp (2, op, args);
 137 }
 138
 139 static inline struct expression *
 140 new_exp_3 (op, bexp, tbranch, fbranch)
 141      enum operator op;
 142      struct expression *bexp;
 143      struct expression *tbranch;
 144      struct expression *fbranch;
 145 {
 146   struct expression *args[3];
 147
 148   args[0] = bexp;
 149   args[1] = tbranch;
 150   args[2] = fbranch;
 151   return new_exp (3, op, args);
 152 }
 153
 154 %}
 155
 156 /* This declares that all operators have the same associativity and the
 157    precedence order as in C.  See [Harbison, Steele: C, A Reference Manual].
 158    There is no unary minus and no bitwise operators.
 159    Operators with the same syntactic behaviour have been merged into a single
 160    token, to save space in the array generated by bison.  */
 161 %right '?'              /*   ?          */
 162 %left '|'               /*   ||         */
 163 %left '&'               /*   &&         */
 164 %left EQUOP2            /*   == !=      */
 165 %left CMPOP2            /*   < > <= >=  */
 166 %left ADDOP2            /*   + -        */
 167 %left MULOP2            /*   * / %      */
 168 %right '!'              /*   !          */
 169
 170 %token <op> EQUOP2 CMPOP2 ADDOP2 MULOP2
 171 %token <num> NUMBER
 172 %type <exp> exp
 173
 174 %%
 175
 176 start:    exp
 177           {
 178             if ($1 == NULL)
 179               YYABORT;
 180             ((struct parse_args *) arg)->res = $1;
 181           }
 182         ;
 183
 184 exp:      exp '?' exp ':' exp
 185           {
 186             $$ = new_exp_3 (qmop, $1, $3, $5);
 187           }
 188         | exp '|' exp
 189           {
 190             $$ = new_exp_2 (lor, $1, $3);
 191           }
 192         | exp '&' exp
 193           {
 194             $$ = new_exp_2 (land, $1, $3);
 195           }
 196         | exp EQUOP2 exp
 197           {
 198             $$ = new_exp_2 ($2, $1, $3);
 199           }
 200         | exp CMPOP2 exp
 201           {
 202             $$ = new_exp_2 ($2, $1, $3);
 203           }
 204         | exp ADDOP2 exp
 205           {
 206             $$ = new_exp_2 ($2, $1, $3);
 207           }
 208         | exp MULOP2 exp
 209           {
 210             $$ = new_exp_2 ($2, $1, $3);
 211           }
 212         | '!' exp
 213           {
 214             $$ = new_exp_1 (lnot, $2);
 215           }
 216         | 'n'
 217           {
 218             $$ = new_exp_0 (var);
 219           }
 220         | NUMBER
 221           {
 222             if (($$ = new_exp_0 (num)) != NULL)
 223               $$->val.num = $1;
 224           }
 225         | '(' exp ')'
 226           {
 227             $$ = $2;
 228           }
 229         ;
 230
 231 %%
 232
 233 void
 234 internal_function
 235 FREE_EXPRESSION (exp)
 236      struct expression *exp;
 237 {
 238   if (exp == NULL)
 239     return;
 240
 241   /* Handle the recursive case.  */
 242   switch (exp->nargs)
 243     {
 244     case 3:
 245       FREE_EXPRESSION (exp->val.args[2]);
 246       /* FALLTHROUGH */
 247     case 2:
 248       FREE_EXPRESSION (exp->val.args[1]);
 249       /* FALLTHROUGH */
 250     case 1:
 251       FREE_EXPRESSION (exp->val.args[0]);
 252       /* FALLTHROUGH */
 253     default:
 254       break;
 255     }
 256
 257   free (exp);
 258 }
 259
 260
 261 static int
 262 yylex (lval, pexp)
 263      YYSTYPE *lval;
 264      const char **pexp;
 265 {
 266   const char *exp = *pexp;
 267   int result;
 268
 269   while (1)
 270     {
 271       if (exp[0] == '\0')
 272         {
 273           *pexp = exp;
 274           return YYEOF;
 275         }
 276
 277       if (exp[0] != ' ' && exp[0] != '\t')
 278         break;
 279
 280       ++exp;
 281     }
 282
 283   result = *exp++;
 284   switch (result)
 285     {
 286     case '0': case '1': case '2': case '3': case '4':
 287     case '5': case '6': case '7': case '8': case '9':
 288       {
 289         unsigned long int n = result - '0';
 290         while (exp[0] >= '0' && exp[0] <= '9')
 291           {
 292             n *= 10;
 293             n += exp[0] - '0';
 294             ++exp;
 295           }
 296         lval->num = n;
 297         result = NUMBER;
 298       }
 299       break;
 300
 301     case '=':
 302       if (exp[0] == '=')
 303         {
 304           ++exp;
 305           lval->op = equal;
 306           result = EQUOP2;
 307         }
 308       else
 309         result = YYERRCODE;
 310       break;
 311
 312     case '!':
 313       if (exp[0] == '=')
 314         {
 315           ++exp;
 316           lval->op = not_equal;
 317           result = EQUOP2;
 318         }
 319       break;
 320
 321     case '&':
 322     case '|':
 323       if (exp[0] == result)
 324         ++exp;
 325       else
 326         result = YYERRCODE;
 327       break;
 328
 329     case '<':
 330       if (exp[0] == '=')
 331         {
 332           ++exp;
 333           lval->op = less_or_equal;
 334         }
 335       else
 336         lval->op = less_than;
 337       result = CMPOP2;
 338       break;
 339
 340     case '>':
 341       if (exp[0] == '=')
 342         {
 343           ++exp;
 344           lval->op = greater_or_equal;
 345         }
 346       else
 347         lval->op = greater_than;
 348       result = CMPOP2;
 349       break;
 350
 351     case '*':
 352       lval->op = mult;
 353       result = MULOP2;
 354       break;
 355
 356     case '/':
 357       lval->op = divide;
 358       result = MULOP2;
 359       break;
 360
 361     case '%':
 362       lval->op = module;
 363       result = MULOP2;
 364       break;
 365
 366     case '+':
 367       lval->op = plus;
 368       result = ADDOP2;
 369       break;
 370
 371     case '-':
 372       lval->op = minus;
 373       result = ADDOP2;
 374       break;
 375
 376     case 'n':
 377     case '?':
 378     case ':':
 379     case '(':
 380     case ')':
 381       /* Nothing, just return the character.  */
 382       break;
 383
 384     case ';':
 385     case '\n':
 386     case '\0':
 387       /* Be safe and let the user call this function again.  */
 388       --exp;
 389       result = YYEOF;
 390       break;
 391
 392     default:
 393       result = YYERRCODE;
 394 #if YYDEBUG != 0
 395       --exp;
 396 #endif
 397       break;
 398     }
 399
 400   *pexp = exp;
 401
 402   return result;
 403 }
 404
 405
 406 static void
 407 yyerror (str)
 408      const char *str;
 409 {
 410   /* Do nothing.  We don't print error messages here.  */
 411 }