1 /* Plural expression evaluation.
2 Copyright (C) 2000-2002 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU Library General Public License as published
6 by the Free Software Foundation; either version 2, or (at your option)
7 any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
13
14 You should have received a copy of the GNU Library General Public
15 License along with this program; if not, write to the Free Software
16 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,
17 USA. */
18
19 #ifndef STATIC
20 #define STATIC static
21 #endif
22
23 /* Evaluate the plural expression and return an index value. */
24 STATIC unsigned long int plural_eval PARAMS ((struct expression *pexp,
25 unsigned long int n))
26 internal_function;
27
28 STATIC
29 unsigned long int
30 internal_function
plural_eval(pexp,n)31 plural_eval (pexp, n)
32 struct expression *pexp;
33 unsigned long int n;
34 {
35 switch (pexp->nargs)
36 {
37 case 0:
38 switch (pexp->operation)
39 {
40 case var:
41 return n;
42 case num:
43 return pexp->val.num;
44 default:
45 break;
46 }
47 /* NOTREACHED */
48 break;
49 case 1:
50 {
51 /* pexp->operation must be lnot. */
52 unsigned long int arg = plural_eval (pexp->val.args[0], n);
53 return ! arg;
54 }
55 case 2:
56 {
57 unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
58 if (pexp->operation == lor)
59 return leftarg || plural_eval (pexp->val.args[1], n);
60 else if (pexp->operation == land)
61 return leftarg && plural_eval (pexp->val.args[1], n);
62 else
63 {
64 unsigned long int rightarg = plural_eval (pexp->val.args[1], n);
65
66 switch (pexp->operation)
67 {
68 case mult:
69 return leftarg * rightarg;
70 case divide:
71 #if !INTDIV0_RAISES_SIGFPE
72 if (rightarg == 0)
73 raise (SIGFPE);
74 #endif
75 return leftarg / rightarg;
76 case module:
77 #if !INTDIV0_RAISES_SIGFPE
78 if (rightarg == 0)
79 raise (SIGFPE);
80 #endif
81 return leftarg % rightarg;
82 case plus:
83 return leftarg + rightarg;
84 case minus:
85 return leftarg - rightarg;
86 case less_than:
87 return leftarg < rightarg;
88 case greater_than:
89 return leftarg > rightarg;
90 case less_or_equal:
91 return leftarg <= rightarg;
92 case greater_or_equal:
93 return leftarg >= rightarg;
94 case equal:
95 return leftarg == rightarg;
96 case not_equal:
97 return leftarg != rightarg;
98 default:
99 break;
100 }
101 }
102 /* NOTREACHED */
103 break;
104 }
105 case 3:
106 {
107 /* pexp->operation must be qmop. */
108 unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
109 return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
110 }
111 }
112 /* NOTREACHED */
113 return 0;
114 }
115