-
Notifications
You must be signed in to change notification settings - Fork 0
/
boolexp.c
185 lines (167 loc) · 3.88 KB
/
boolexp.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
#include "copyright.h"
#include <stdlib.h>
#include <ctype.h>
#include "db.h"
#include "match.h"
#include "externs.h"
#include "config.h"
#include "interface.h"
int eval_boolexp(dbref player, struct boolexp *b)
{
if(b == TRUE_BOOLEXP) {
return 1;
} else {
switch(b->type) {
case BOOLEXP_AND:
return (eval_boolexp(player, b->sub1)
&& eval_boolexp(player, b->sub2));
case BOOLEXP_OR:
return (eval_boolexp(player, b->sub1)
|| eval_boolexp(player, b->sub2));
case BOOLEXP_NOT:
return !eval_boolexp(player, b->sub1);
case BOOLEXP_CONST:
return (b->thing == player
|| member(b->thing, db[player].contents));
default:
abort(); /* bad type */
return 0;
}
}
}
/* If the parser returns TRUE_BOOLEXP, you lose */
/* TRUE_BOOLEXP cannot be typed in by the user; use @unlock instead */
static const char *parsebuf;
static dbref parse_player;
static void skip_whitespace(void)
{
while(*parsebuf && isspace(*parsebuf)) parsebuf++;
}
static struct boolexp *parse_boolexp_E(void); /* defined below */
/* F -> (E); F -> !F; F -> object identifier */
static struct boolexp *parse_boolexp_F(void)
{
struct boolexp *b;
char *p;
char buf[BUFFER_LEN];
char msg[2 * BUFFER_LEN];
skip_whitespace();
switch(*parsebuf) {
case '(':
parsebuf++;
b = parse_boolexp_E();
skip_whitespace();
if(b == TRUE_BOOLEXP || *parsebuf++ != ')') {
free_boolexp(b);
return TRUE_BOOLEXP;
} else {
return b;
}
/* break; */
case NOT_TOKEN:
parsebuf++;
b = (struct boolexp *) malloc(sizeof(struct boolexp));
b->type = BOOLEXP_NOT;
b->sub1 = parse_boolexp_F();
if(b->sub1 == TRUE_BOOLEXP) {
free((void *) b);
return TRUE_BOOLEXP;
} else {
return b;
}
/* break */
default:
/* must have hit an object ref */
/* load the name into our buffer */
p = buf;
while(*parsebuf
&& *parsebuf != AND_TOKEN
&& *parsebuf != OR_TOKEN
&& *parsebuf != ')') {
*p++ = *parsebuf++;
}
/* strip trailing whitespace */
*p-- = '\0';
while(isspace(*p)) *p-- = '\0';
b = (struct boolexp *) malloc(sizeof(struct boolexp));
b->type = BOOLEXP_CONST;
/* do the match */
init_match(parse_player, buf, TYPE_THING);
match_neighbor();
match_possession();
match_me();
match_absolute();
match_player();
b->thing = match_result();
if(b->thing == NOTHING) {
sprintf(msg, "I don't see %s here.", buf);
notify(parse_player, msg);
free((void *) b);
return TRUE_BOOLEXP;
} else if(b->thing == AMBIGUOUS) {
sprintf(msg, "I don't know which %s you mean!", buf);
notify(parse_player, msg);
free((void *) b);
return TRUE_BOOLEXP;
} else {
return b;
}
/* break */
}
}
/* T -> F; T -> F & T */
static struct boolexp *parse_boolexp_T(void)
{
struct boolexp *b;
struct boolexp *b2;
if((b = parse_boolexp_F()) == TRUE_BOOLEXP) {
return b;
} else {
skip_whitespace();
if(*parsebuf == AND_TOKEN) {
parsebuf++;
b2 = (struct boolexp *) malloc(sizeof(struct boolexp));
b2->type = BOOLEXP_AND;
b2->sub1 = b;
if((b2->sub2 = parse_boolexp_T()) == TRUE_BOOLEXP) {
free_boolexp(b2);
return TRUE_BOOLEXP;
} else {
return b2;
}
} else {
return b;
}
}
}
/* E -> T; E -> T | E */
static struct boolexp *parse_boolexp_E(void)
{
struct boolexp *b;
struct boolexp *b2;
if((b = parse_boolexp_T()) == TRUE_BOOLEXP) {
return b;
} else {
skip_whitespace();
if(*parsebuf == OR_TOKEN) {
parsebuf++;
b2 = (struct boolexp *) malloc(sizeof(struct boolexp));
b2->type = BOOLEXP_OR;
b2->sub1 = b;
if((b2->sub2 = parse_boolexp_E()) == TRUE_BOOLEXP) {
free_boolexp(b2);
return TRUE_BOOLEXP;
} else {
return b2;
}
} else {
return b;
}
}
}
struct boolexp *parse_boolexp(dbref player, const char *buf)
{
parsebuf = buf;
parse_player = player;
return parse_boolexp_E();
}