%{

/* Expression parsing for plural form selection.

   Copyright (C) 2000, 2001 Free Software Foundation, Inc.

   Written by Ulrich Drepper <drepper@cygnus.com>, 2000.

   This program is free software; you can redistribute it and/or modify it

   under the terms of the GNU Library General Public License as published

   by the Free Software Foundation; either version 2, or (at your option)

   any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public

   License along with this program; if not, write to the Free Software

   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,

   USA.  */

/* The bison generated parser uses alloca.  AIX 3 forces us to put this

   declaration at the beginning of the file.  The declaration in bison's

   skeleton file comes too late.  This must come before <config.h>

   because <config.h> may include arbitrary system headers.  */

#if defined _AIX && !defined __GNUC__

 #pragma alloca

#endif

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <stddef.h>

#include <stdlib.h>

#include "plural-exp.h"

/* The main function generated by the parser is called __gettextparse,

   but we want it to be called PLURAL_PARSE.  */

#ifndef _LIBC

# define __gettextparse PLURAL_PARSE

#endif

#define YYLEX_PARAM	&((struct parse_args *) arg)->cp

#define YYPARSE_PARAM	arg

%}

%pure_parser

%expect 7

%union {

  unsigned long int num;

  enum operator op;

  struct expression *exp;

}

%{

/* Prototypes for local functions.  */

static struct expression *new_exp PARAMS ((int nargs, enum operator op,

					   struct expression * const *args));

static inline struct expression *new_exp_0 PARAMS ((enum operator op));

static inline struct expression *new_exp_1 PARAMS ((enum operator op,

						   struct expression *right));

static struct expression *new_exp_2 PARAMS ((enum operator op,

					     struct expression *left,

					     struct expression *right));

static inline struct expression *new_exp_3 PARAMS ((enum operator op,

						   struct expression *bexp,

						   struct expression *tbranch,

						   struct expression *fbranch));

static int yylex PARAMS ((YYSTYPE *lval, const char **pexp));

static void yyerror PARAMS ((const char *str));

/* Allocation of expressions.  */

static struct expression *

new_exp (nargs, op, args)

     int nargs;

     enum operator op;

     struct expression * const *args;

{

  int i;

  struct expression *newp;

  /* If any of the argument could not be malloc'ed, just return NULL.  */

  for (i = nargs - 1; i >= 0; i--)

    if (args[i] == NULL)

      goto fail;

  /* Allocate a new expression.  */

  newp = (struct expression *) malloc (sizeof (*newp));

  if (newp != NULL)

    {

      newp->nargs = nargs;

      newp->operation = op;

      for (i = nargs - 1; i >= 0; i--)

	newp->val.args[i] = args[i];

      return newp;

    }

 fail:

  for (i = nargs - 1; i >= 0; i--)

    FREE_EXPRESSION (args[i]);

  return NULL;

}

static inline struct expression *

new_exp_0 (op)

     enum operator op;

{

  return new_exp (0, op, NULL);

}

static inline struct expression *

new_exp_1 (op, right)

     enum operator op;

     struct expression *right;

{

  struct expression *args[1];

  args[0] = right;

  return new_exp (1, op, args);

}

static struct expression *

new_exp_2 (op, left, right)

     enum operator op;

     struct expression *left;

     struct expression *right;

{

  struct expression *args[2];

  args[0] = left;

  args[1] = right;

  return new_exp (2, op, args);

}

static inline struct expression *

new_exp_3 (op, bexp, tbranch, fbranch)

     enum operator op;

     struct expression *bexp;

     struct expression *tbranch;

     struct expression *fbranch;

{

  struct expression *args[3];

  args[0] = bexp;

  args[1] = tbranch;

  args[2] = fbranch;

  return new_exp (3, op, args);

}

%}

/* This declares that all operators have the same associativity and the

   precedence order as in C.  See [Harbison, Steele: C, A Reference Manual].

   There is no unary minus and no bitwise operators.

   Operators with the same syntactic behaviour have been merged into a single

   token, to save space in the array generated by bison.  */

%right '?'		/*   ?		*/

%left '|'		/*   ||		*/

%left '&'		/*   &&		*/

%left EQUOP2		/*   == !=	*/

%left CMPOP2		/*   < > <= >=	*/

%left ADDOP2		/*   + -	*/

%left MULOP2		/*   * / %	*/

%right '!'		/*   !		*/

%token <op> EQUOP2 CMPOP2 ADDOP2 MULOP2

%token <num> NUMBER

%type <exp> exp

%%

start:	  exp

	  {

	    if ($1 == NULL)

	      YYABORT;

	    ((struct parse_args *) arg)->res = $1;

	  }

	;

exp:	  exp '?' exp ':' exp

	  {

	    $$ = new_exp_3 (qmop, $1, $3, $5);

	  }

	| exp '|' exp

	  {

	    $$ = new_exp_2 (lor, $1, $3);

	  }

	| exp '&' exp

	  {

	    $$ = new_exp_2 (land, $1, $3);

	  }

	| exp EQUOP2 exp

	  {

	    $$ = new_exp_2 ($2, $1, $3);

	  }

	| exp CMPOP2 exp

	  {

	    $$ = new_exp_2 ($2, $1, $3);

	  }

	| exp ADDOP2 exp

	  {

	    $$ = new_exp_2 ($2, $1, $3);

	  }

	| exp MULOP2 exp

	  {

	    $$ = new_exp_2 ($2, $1, $3);

	  }

	| '!' exp

	  {

	    $$ = new_exp_1 (lnot, $2);

	  }

	| 'n'

	  {

	    $$ = new_exp_0 (var);

	  }

	| NUMBER

	  {

	    if (($$ = new_exp_0 (num)) != NULL)

	      $$->val.num = $1;

	  }

	| '(' exp ')'

	  {

	    $$ = $2;

	  }

	;

%%

void

internal_function

FREE_EXPRESSION (exp)

     struct expression *exp;

{

  if (exp == NULL)

    return;

  /* Handle the recursive case.  */

  switch (exp->nargs)

    {

    case 3:

      FREE_EXPRESSION (exp->val.args[2]);

      /* FALLTHROUGH */

    case 2:

      FREE_EXPRESSION (exp->val.args[1]);

      /* FALLTHROUGH */

    case 1:

      FREE_EXPRESSION (exp->val.args[0]);

      /* FALLTHROUGH */

    default:

      break;

    }

  free (exp);

}

static int

yylex (lval, pexp)

     YYSTYPE *lval;

     const char **pexp;

{

  const char *exp = *pexp;

  int result;

  while (1)

    {

      if (exp[0] == '\0')

	{

	  *pexp = exp;

	  return YYEOF;

	}

      if (exp[0] != ' ' && exp[0] != '\t')

	break;

      ++exp;

    }

  result = *exp++;

  switch (result)

    {

    case '0': case '1': case '2': case '3': case '4':

    case '5': case '6': case '7': case '8': case '9':

      {

	unsigned long int n = result - '0';

	while (exp[0] >= '0' && exp[0] <= '9')

	  {

	    n *= 10;

	    n += exp[0] - '0';

	    ++exp;

	  }

	lval->num = n;

	result = NUMBER;

      }

      break;

    case '=':

      if (exp[0] == '=')

	{

	  ++exp;

	  lval->op = equal;

	  result = EQUOP2;

	}

      else

	result = YYERRCODE;

      break;

    case '!':

      if (exp[0] == '=')

	{

	  ++exp;

	  lval->op = not_equal;

	  result = EQUOP2;

	}

      break;

    case '&':

    case '|':

      if (exp[0] == result)

	++exp;

      else

	result = YYERRCODE;

      break;

    case '<':

      if (exp[0] == '=')

	{

	  ++exp;

	  lval->op = less_or_equal;

	}

      else

	lval->op = less_than;

      result = CMPOP2;

      break;

    case '>':

      if (exp[0] == '=')

	{

	  ++exp;

	  lval->op = greater_or_equal;

	}

      else

	lval->op = greater_than;

      result = CMPOP2;

      break;

    case '*':

      lval->op = mult;

      result = MULOP2;

      break;

    case '/':

      lval->op = divide;

      result = MULOP2;

      break;

    case '%':

      lval->op = module;

      result = MULOP2;

      break;

    case '+':

      lval->op = plus;

      result = ADDOP2;

      break;

    case '-':

      lval->op = minus;

      result = ADDOP2;

      break;

    case 'n':

    case '?':

    case ':':

    case '(':

    case ')':

      /* Nothing, just return the character.  */

      break;

    case ';':

    case '\n':

    case '\0':

      /* Be safe and let the user call this function again.  */

      --exp;

      result = YYEOF;

      break;

    default:

      result = YYERRCODE;

#if YYDEBUG != 0

      --exp;

#endif

      break;

    }

  *pexp = exp;

  return result;

}

static void

yyerror (str)

     const char *str;

{

  /* Do nothing.  We don't print error messages here.  */

}