intl/plural.y

   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.  */
  57
  58 #ifndef __GNUC__
  59 #define inline /* nothing: don't inline if the compiler is not GCC */
  60 #endif
  61
  62 static struct expression *new_exp PARAMS ((int nargs, enum operator op,
  63                                            struct expression * const *args));
  64 static inline struct expression *new_exp_0 PARAMS ((enum operator op));
  65 static inline struct expression *new_exp_1 PARAMS ((enum operator op,
  66                                                    struct expression *right));
  67 static struct expression *new_exp_2 PARAMS ((enum operator op,
  68                                              struct expression *left,
  69                                              struct expression *right));
  70 static inline struct expression *new_exp_3 PARAMS ((enum operator op,
  71                                                    struct expression *bexp,
  72                                                    struct expression *tbranch,
  73                                                    struct expression *fbranch));
  74 static int yylex PARAMS ((YYSTYPE *lval, const char **pexp));
  75 static void yyerror PARAMS ((const char *str));
  76
  77 /* Allocation of expressions.  */
  78
  79 static struct expression *
  80 new_exp (nargs, op, args)
  81      int nargs;
  82      enum operator op;
  83      struct expression * const *args;
  84 {
  85   int i;
  86   struct expression *newp;
  87
  88   /* If any of the argument could not be malloc'ed, just return NULL.  */
  89   for (i = nargs - 1; i >= 0; i--)
  90     if (args[i] == NULL)
  91       goto fail;
  92
  93   /* Allocate a new expression.  */
  94   newp = (struct expression *) malloc (sizeof (*newp));
  95   if (newp != NULL)
  96     {
  97       newp->nargs = nargs;
  98       newp->operation = op;
  99       for (i = nargs - 1; i >= 0; i--)
 100         newp->val.args[i] = args[i];
 101       return newp;
 102     }
 103
 104  fail:
 105   for (i = nargs - 1; i >= 0; i--)
 106     FREE_EXPRESSION (args[i]);
 107
 108   return NULL;
 109 }
 110
 111 static inline struct expression *
 112 new_exp_0 (op)
 113      enum operator op;
 114 {
 115   return new_exp (0, op, NULL);
 116 }
 117
 118 static inline struct expression *
 119 new_exp_1 (op, right)
 120      enum operator op;
 121      struct expression *right;
 122 {
 123   struct expression *args[1];
 124
 125   args[0] = right;
 126   return new_exp (1, op, args);
 127 }
 128
 129 static struct expression *
 130 new_exp_2 (op, left, right)
 131      enum operator op;
 132      struct expression *left;
 133      struct expression *right;
 134 {
 135   struct expression *args[2];
 136
 137   args[0] = left;
 138   args[1] = right;
 139   return new_exp (2, op, args);
 140 }
 141
 142 static inline struct expression *
 143 new_exp_3 (op, bexp, tbranch, fbranch)
 144      enum operator op;
 145      struct expression *bexp;
 146      struct expression *tbranch;
 147      struct expression *fbranch;
 148 {
 149   struct expression *args[3];
 150
 151   args[0] = bexp;
 152   args[1] = tbranch;
 153   args[2] = fbranch;
 154   return new_exp (3, op, args);
 155 }
 156
 157 %}
 158
 159 /* This declares that all operators have the same associativity and the
 160    precedence order as in C.  See [Harbison, Steele: C, A Reference Manual].
 161    There is no unary minus and no bitwise operators.
 162    Operators with the same syntactic behaviour have been merged into a single
 163    token, to save space in the array generated by bison.  */
 164 %right '?'              /*   ?          */
 165 %left '|'               /*   ||         */
 166 %left '&'               /*   &&         */
 167 %left EQUOP2            /*   == !=      */
 168 %left CMPOP2            /*   < > <= >=  */
 169 %left ADDOP2            /*   + -        */
 170 %left MULOP2            /*   * / %      */
 171 %right '!'              /*   !          */
 172
 173 %token <op> EQUOP2 CMPOP2 ADDOP2 MULOP2
 174 %token <num> NUMBER
 175 %type <exp> exp
 176
 177 %%
 178
 179 start:    exp
 180           {
 181             if ($1 == NULL)
 182               YYABORT;
 183             ((struct parse_args *) arg)->res = $1;
 184           }
 185         ;
 186
 187 exp:      exp '?' exp ':' exp
 188           {
 189             $$ = new_exp_3 (qmop, $1, $3, $5);
 190           }
 191         | exp '|' exp
 192           {
 193             $$ = new_exp_2 (lor, $1, $3);
 194           }
 195         | exp '&' exp
 196           {
 197             $$ = new_exp_2 (land, $1, $3);
 198           }
 199         | exp EQUOP2 exp
 200           {
 201             $$ = new_exp_2 ($2, $1, $3);
 202           }
 203         | exp CMPOP2 exp
 204           {
 205             $$ = new_exp_2 ($2, $1, $3);
 206           }
 207         | exp ADDOP2 exp
 208           {
 209             $$ = new_exp_2 ($2, $1, $3);
 210           }
 211         | exp MULOP2 exp
 212           {
 213             $$ = new_exp_2 ($2, $1, $3);
 214           }
 215         | '!' exp
 216           {
 217             $$ = new_exp_1 (lnot, $2);
 218           }
 219         | 'n'
 220           {
 221             $$ = new_exp_0 (var);
 222           }
 223         | NUMBER
 224           {
 225             if (($$ = new_exp_0 (num)) != NULL)
 226               $$->val.num = $1;
 227           }
 228         | '(' exp ')'
 229           {
 230             $$ = $2;
 231           }
 232         ;
 233
 234 %%
 235
 236 void
 237 internal_function
 238 FREE_EXPRESSION (exp)
 239      struct expression *exp;
 240 {
 241   if (exp == NULL)
 242     return;
 243
 244   /* Handle the recursive case.  */
 245   switch (exp->nargs)
 246     {
 247     case 3:
 248       FREE_EXPRESSION (exp->val.args[2]);
 249       /* FALLTHROUGH */
 250     case 2:
 251       FREE_EXPRESSION (exp->val.args[1]);
 252       /* FALLTHROUGH */
 253     case 1:
 254       FREE_EXPRESSION (exp->val.args[0]);
 255       /* FALLTHROUGH */
 256     default:
 257       break;
 258     }
 259
 260   free (exp);
 261 }
 262
 263
 264 static int
 265 yylex (lval, pexp)
 266      YYSTYPE *lval;
 267      const char **pexp;
 268 {
 269   const char *exp = *pexp;
 270   int result;
 271
 272   while (1)
 273     {
 274       if (exp[0] == '\0')
 275         {
 276           *pexp = exp;
 277           return YYEOF;
 278         }
 279
 280       if (exp[0] != ' ' && exp[0] != '\t')
 281         break;
 282
 283       ++exp;
 284     }
 285
 286   result = *exp++;
 287   switch (result)
 288     {
 289     case '0': case '1': case '2': case '3': case '4':
 290     case '5': case '6': case '7': case '8': case '9':
 291       {
 292         unsigned long int n = result - '0';
 293         while (exp[0] >= '0' && exp[0] <= '9')
 294           {
 295             n *= 10;
 296             n += exp[0] - '0';
 297             ++exp;
 298           }
 299         lval->num = n;
 300         result = NUMBER;
 301       }
 302       break;
 303
 304     case '=':
 305       if (exp[0] == '=')
 306         {
 307           ++exp;
 308           lval->op = equal;
 309           result = EQUOP2;
 310         }
 311       else
 312         result = YYERRCODE;
 313       break;
 314
 315     case '!':
 316       if (exp[0] == '=')
 317         {
 318           ++exp;
 319           lval->op = not_equal;
 320           result = EQUOP2;
 321         }
 322       break;
 323
 324     case '&':
 325     case '|':
 326       if (exp[0] == result)
 327         ++exp;
 328       else
 329         result = YYERRCODE;
 330       break;
 331
 332     case '<':
 333       if (exp[0] == '=')
 334         {
 335           ++exp;
 336           lval->op = less_or_equal;
 337         }
 338       else
 339         lval->op = less_than;
 340       result = CMPOP2;
 341       break;
 342
 343     case '>':
 344       if (exp[0] == '=')
 345         {
 346           ++exp;
 347           lval->op = greater_or_equal;
 348         }
 349       else
 350         lval->op = greater_than;
 351       result = CMPOP2;
 352       break;
 353
 354     case '*':
 355       lval->op = mult;
 356       result = MULOP2;
 357       break;
 358
 359     case '/':
 360       lval->op = divide;
 361       result = MULOP2;
 362       break;
 363
 364     case '%':
 365       lval->op = module;
 366       result = MULOP2;
 367       break;
 368
 369     case '+':
 370       lval->op = plus;
 371       result = ADDOP2;
 372       break;
 373
 374     case '-':
 375       lval->op = minus;
 376       result = ADDOP2;
 377       break;
 378
 379     case 'n':
 380     case '?':
 381     case ':':
 382     case '(':
 383     case ')':
 384       /* Nothing, just return the character.  */
 385       break;
 386
 387     case ';':
 388     case '\n':
 389     case '\0':
 390       /* Be safe and let the user call this function again.  */
 391       --exp;
 392       result = YYEOF;
 393       break;
 394
 395     default:
 396       result = YYERRCODE;
 397 #if YYDEBUG != 0
 398       --exp;
 399 #endif
 400       break;
 401     }
 402
 403   *pexp = exp;
 404
 405   return result;
 406 }
 407
 408
 409 static void
 410 yyerror (str)
 411      const char *str;
 412 {
 413   /* Do nothing.  We don't print error messages here.  */
 414 }