gnu/dist/grep/intl/eval-plural.h

   1 /*      $NetBSD$        */
   2
   3 /* Plural expression evaluation.
   4    Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    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
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 #ifndef STATIC
  21 #define STATIC static
  22 #endif
  23
  24 /* Evaluate the plural expression and return an index value.  */
  25 STATIC unsigned long int plural_eval PARAMS ((struct expression *pexp,
  26                                               unsigned long int n))
  27      internal_function;
  28
  29 STATIC
  30 unsigned long int
  31 internal_function
  32 plural_eval (pexp, n)
  33      struct expression *pexp;
  34      unsigned long int n;
  35 {
  36   switch (pexp->nargs)
  37     {
  38     case 0:
  39       switch (pexp->operation)
  40         {
  41         case var:
  42           return n;
  43         case num:
  44           return pexp->val.num;
  45         default:
  46           break;
  47         }
  48       /* NOTREACHED */
  49       break;
  50     case 1:
  51       {
  52         /* pexp->operation must be lnot.  */
  53         unsigned long int arg = plural_eval (pexp->val.args[0], n);
  54         return ! arg;
  55       }
  56     case 2:
  57       {
  58         unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
  59         if (pexp->operation == lor)
  60           return leftarg || plural_eval (pexp->val.args[1], n);
  61         else if (pexp->operation == land)
  62           return leftarg && plural_eval (pexp->val.args[1], n);
  63         else
  64           {
  65             unsigned long int rightarg = plural_eval (pexp->val.args[1], n);
  66
  67             switch (pexp->operation)
  68               {
  69               case mult:
  70                 return leftarg * rightarg;
  71               case divide:
  72                 return leftarg / rightarg;
  73               case module:
  74                 return leftarg % rightarg;
  75               case plus:
  76                 return leftarg + rightarg;
  77               case minus:
  78                 return leftarg - rightarg;
  79               case less_than:
  80                 return leftarg < rightarg;
  81               case greater_than:
  82                 return leftarg > rightarg;
  83               case less_or_equal:
  84                 return leftarg <= rightarg;
  85               case greater_or_equal:
  86                 return leftarg >= rightarg;
  87               case equal:
  88                 return leftarg == rightarg;
  89               case not_equal:
  90                 return leftarg != rightarg;
  91               default:
  92                 break;
  93               }
  94           }
  95         /* NOTREACHED */
  96         break;
  97       }
  98     case 3:
  99       {
 100         /* pexp->operation must be qmop.  */
 101         unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
 102         return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
 103       }
 104     }
 105   /* NOTREACHED */
 106   return 0;
 107 }