blob: ff21b7b644cd7c032cfac7010ab54660a2b92e92 (
plain) (
blame)
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
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
#include <cstdio>
#include <cctype>
#include <sstream>
#include "parser.h"
#include "exc.h"
#include "consts.h"
#include "builtin.h"
using std::stringstream;
static char buff[TOKEN_BUFF_SIZE];
static FrameObj *parse_stack[PARSE_STACK_SIZE];
extern Pair *empty_list;
Tokenizor::Tokenizor() : stream(stdin), buff_ptr(buff), escaping(false) {}
void Tokenizor::set_stream(FILE *_stream) {
stream = _stream;
}
#define IS_NEWLINE(ch) \
((ch) == '\n')
#define IS_QUOTE(ch) \
((ch) == '\"')
#define IS_SLASH(ch) \
((ch) == '\\')
#define IS_BRACKET(ch) \
((ch) == '(' || (ch) == ')')
#define IS_SPACE(ch) \
((ch) == ' ' || (ch) == '\t' || IS_NEWLINE(ch))
#define IS_COMMENT(ch) \
((ch) == ';')
#define IS_LITERAL(ch) \
((ch) == '\'')
#define IS_DELIMITER(ch) \
(IS_BRACKET(ch) || IS_SPACE(ch) || \
IS_COMMENT(ch) || IS_QUOTE(ch))
#define POP \
do { \
*buff_ptr = 0; \
ret = string(buff); \
buff_ptr = buff; \
} while (0)
#define TOP (*(buff_ptr - 1))
void str_to_lower(string &str) {
size_t len = str.length();
for (int i = 0; i < len; i++)
if ('A' <= str[i] && str[i] <= 'Z')
str[i] -= 'A' - 'a';
}
bool Tokenizor::get_token(string &ret) {
char ch;
bool flag = false;
while (fread(&ch, 1, 1, stream))
{
if (escaping)
{
escaping = false;
switch (ch)
{
case '\\': *buff_ptr++ = '\\'; break;
case '\"': *buff_ptr++ = '\"'; break;
case 'n': *buff_ptr++ = '\n'; break;
case 't': *buff_ptr++ = '\t'; break;
default: {
buff_ptr = buff;
throw TokenError(string("") + ch,
PAR_ERR_ILLEGAL_CHAR_IN_ESC);
}
}
}
else
{
bool in_quote = buff_ptr != buff && IS_QUOTE(*buff);
if (buff_ptr != buff)
{
if (buff_ptr - buff == 1 && IS_LITERAL(TOP))
{
POP;
flag = true;
}
else if ((IS_BRACKET(TOP) || IS_DELIMITER(ch)))
{
if (IS_COMMENT(*buff))
{
if (IS_NEWLINE(ch)) buff_ptr = buff;
else buff_ptr = buff + 1;
}
else if (!in_quote) // not in a double-quote
{
if (!(buff_ptr - buff == 1 && ch == '(' && TOP == '#'))
{
POP;
flag = true;
}
}
else if (IS_QUOTE(ch))
{
// in a double-quote which is being enclosed
*buff_ptr++ = '\"';
POP;
return true; // prevent duplicate quote sign
}
}
}
if (in_quote || !IS_SPACE(ch))
{
if (in_quote && IS_SLASH(ch))
escaping = true;
else
*buff_ptr++ = ch;
}
if (flag)
{
str_to_lower(ret);
return true;
}
}
}
if (buff_ptr != buff) POP;
return false; // can't read more
}
ASTGenerator::ASTGenerator() {}
EvalObj *ASTGenerator::to_obj(const string &str) {
EvalObj *res = NULL;
if ((res = BoolObj::from_string(str))) return res;
if ((res = CharObj::from_string(str))) return res;
if ((res = IntNumObj::from_string(str))) return res;
if ((res = RatNumObj::from_string(str))) return res;
if ((res = RealNumObj::from_string(str))) return res;
if ((res = CompNumObj::from_string(str))) return res;
if ((res = StrObj::from_string(str))) return res;
return new SymObj(str); // otherwise we assume it a symbol
}
#define TO_EVAL(ptr) \
(static_cast<EvalObj*>(ptr))
#define TO_BRACKET(ptr) \
(static_cast<ParseBracket*>(ptr))
#define IS_BRAKET(ptr) \
((ptr)->is_parse_bracket())
Pair *ASTGenerator::absorb(Tokenizor *tk) {
FrameObj **top_ptr = parse_stack;
for (;;)
{
if (top_ptr - parse_stack > 1 &&
!IS_BRAKET(*(top_ptr - 1)) &&
IS_BRAKET(*(top_ptr - 2)))
{
ParseBracket *bptr = TO_BRACKET(*(top_ptr - 2));
if (bptr->btype == 2)
{
top_ptr -= 2;
Pair *lst_cdr = new Pair(TO_EVAL(*(top_ptr + 1)), empty_list);
Pair *lst = new Pair(new SymObj("quote"), lst_cdr);
lst->next = lst_cdr;
lst_cdr->next = NULL;
*top_ptr++ = lst;
}
}
if (top_ptr > parse_stack && !IS_BRAKET(*parse_stack))
return new Pair(TO_EVAL(*(top_ptr - 1)), empty_list);
string token;
if (!tk->get_token(token)) return NULL;
if (token == "(") // a list
*top_ptr++ = new ParseBracket(0);
else if (token == "#(") // a vector
*top_ptr++ = new ParseBracket(1);
else if (token == "\'") // syntatic sugar for quote
*top_ptr++ = new ParseBracket(2);
else if (token == ")")
{
if (top_ptr == parse_stack)
throw NormalError(READ_ERR_UNEXPECTED_RIGHT_BRACKET);
EvalObj *lst = empty_list;
bool improper = false;
while (top_ptr >= parse_stack && !IS_BRAKET(*(--top_ptr)))
{
EvalObj *obj = TO_EVAL(*top_ptr);
if (obj->is_sym_obj() && static_cast<SymObj*>(obj)->val == ".")
{
if (improper ||
lst == empty_list ||
TO_PAIR(lst)->cdr != empty_list)
throw NormalError(PAR_ERR_IMPROPER_PAIR);
improper = true;
lst = TO_PAIR(lst)->car;
}
else
{
Pair *_lst = new Pair(obj, lst); // Collect the list
_lst->next = lst->is_pair_obj() ? TO_PAIR(lst) : NULL;
lst = _lst;
}
}
ParseBracket *bptr = TO_BRACKET(*top_ptr);
if (bptr->btype == 0)
*top_ptr++ = lst;
else if (bptr->btype == 1)
{
if (improper) throw NormalError(PAR_ERR_IMPROPER_VECT);
VecObj *vec = new VecObj();
for (Pair *ptr = TO_PAIR(lst); ptr != empty_list; ptr = TO_PAIR(ptr->cdr))
vec->push_back(ptr->car);
*top_ptr++ = vec;
}
}
else
*top_ptr++ = ASTGenerator::to_obj(token);
}
}
|