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
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
|
#ifndef INCLUDE_lexerlexer
#define INCLUDE_lexerlexer
#include "token.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct {
const char *buf;
int pos;
int line;
int col;
} _LX;
static void perror_at(_LX *lx, const char *msg) {
fprintf(stderr, "[LEXER] Error at line %d, column %d: %s\n", lx->line, lx->col, msg);
exit(1);
}
#define sic static inline char
#define sii static inline int
#define siv static inline void
#define sit static inline _T
sic lxpeek(_LX *lx) { return lx->buf[lx->pos]; }
sic lxget(_LX *lx) { return lx->buf[lx->pos++]; }
static inline char *lx_strdup_checked(_LX *lx, const char *s) {
char *p = strdup(s);
if (!p) {
perror_at(lx, "out of memory");
}
return p;
}
siv lxskipws(_LX *lx) {
while (lxpeek(lx) == ' ' || lxpeek(lx) == '\t') {
if (lxpeek(lx) == '\t') lx->col += 8; else lx->col++;
lxget(lx);
}
}
sit lxnext(_LX *lx) {
lxskipws(lx);
char c = lxpeek(lx);
if (c == 0)
return (_T){TK_EOF, 0, NULL};
// Track newlines
if (c == '\n') {
lx->line++;
lx->col = 0;
lxget(lx);
return lxnext(lx);
}
// Comments: // and /* */
if (c == '/') {
// peek one ahead
int saved = lx->pos;
lxget(lx);
char c2 = lxpeek(lx);
if (c2 == '/') {
while (lxpeek(lx) != '\n' && lxpeek(lx) != 0) lxget(lx);
return lxnext(lx);
} else if (c2 == '*') {
lxget(lx); // consume '*'
for (;;) {
char ch = lxpeek(lx);
if (ch == 0) break; // unterminated, let it go
lxget(lx);
if (ch == '\n') { lx->line++; lx->col = 0; }
if (ch == '*' && lxpeek(lx) == '/') { lxget(lx); break; }
}
return lxnext(lx);
} else {
// not a comment — put position back, fall through to normal '/' handling
lx->pos = saved;
}
}
if (isalpha(c) || c == '_') {
int start = lx->pos;
while (isalnum(lxpeek(lx)) || lxpeek(lx) == '_')
lxget(lx);
int len = lx->pos - start;
char *text = strndup(lx->buf + start, len);
if (!text) {
perror_at(lx, "out of memory");
}
return (_T){checkkw(text), 0, text};
}
if (isdigit(c)) {
int start = lx->pos;
while (isdigit(lxpeek(lx)))
lxget(lx);
int len = lx->pos - start;
char *text = strndup(lx->buf + start, len);
if (!text) {
perror_at(lx, "out of memory");
}
return (_T){TK_NUMBER, atoi(text), text};
}
lxget(lx);
lx->col++;
// handle multi-char tokens
if (c == '=') {
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_EQ,0,lx_strdup_checked(lx,"==")}; }
return (_T){TK_ASSIGN, 0, lx_strdup_checked(lx,"=")};
}
if (c == '!') {
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_NE,0,lx_strdup_checked(lx,"!=")}; }
return (_T){TK_BANG,0,lx_strdup_checked(lx,"!")};
}
if (c == '<') {
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_LE,0,lx_strdup_checked(lx,"<=")}; }
if (lxpeek(lx) == '<') { lxget(lx); lx->col++; return (_T){TK_SHL,0,lx_strdup_checked(lx,"<<")}; }
return (_T){TK_LT,0,lx_strdup_checked(lx,"<")};
}
if (c == '>') {
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_GE,0,lx_strdup_checked(lx,">=")}; }
if (lxpeek(lx) == '>') { lxget(lx); lx->col++; return (_T){TK_SHR,0,lx_strdup_checked(lx,">>")}; }
return (_T){TK_GT,0,lx_strdup_checked(lx,">")};
}
if (c == '&') {
if (lxpeek(lx) == '&') { lxget(lx); lx->col++; return (_T){TK_AND,0,lx_strdup_checked(lx,"&&")}; }
}
if (c == '|') {
if (lxpeek(lx) == '|') { lxget(lx); lx->col++; return (_T){TK_OR,0,lx_strdup_checked(lx,"||")}; }
}
if (c == '"') {
// String literal — decode escape sequences into a fresh buffer
int cap = 64, dlen = 0;
char *decoded = (char*)malloc(cap);
if (!decoded) perror_at(lx, "out of memory");
while (lxpeek(lx) != '"' && lxpeek(lx) != 0) {
char ch;
if (lxpeek(lx) == '\\') {
lxget(lx); // consume backslash
char esc = (char)lxget(lx);
switch (esc) {
case 'n': ch = '\n'; break;
case 't': ch = '\t'; break;
case 'r': ch = '\r'; break;
case '0': ch = '\0'; break;
case '\\': ch = '\\'; break;
case '"': ch = '"'; break;
case '\'': ch = '\''; break;
default: ch = esc; break;
}
} else {
ch = (char)lxget(lx);
}
if (dlen + 2 > cap) {
cap *= 2;
char *tmp = (char*)realloc(decoded, cap);
if (!tmp) { free(decoded); perror_at(lx, "out of memory"); }
decoded = tmp;
}
decoded[dlen++] = ch;
}
decoded[dlen] = '\0';
if (lxpeek(lx) == '"') {
lxget(lx); // consume closing quote
return (_T){TK_STRING, 0, decoded};
} else {
free(decoded);
perror_at(lx, "unterminated string literal");
}
}
if (c == '\'') {
/* Character literal: decode a single char or escape sequence and emit
* TK_CHARLIT with the integer value in .val so the parser never needs
* to reason about escape sequences. */
int char_val = 0;
if (lxpeek(lx) == '\\') {
lxget(lx); /* consume backslash */
char esc = lxget(lx);
switch (esc) {
case 'n': char_val = '\n'; break;
case 't': char_val = '\t'; break;
case 'r': char_val = '\r'; break;
case '0': char_val = '\0'; break;
case '\\': char_val = '\\'; break;
case '\'': char_val = '\''; break;
case '"': char_val = '"'; break;
case 'a': char_val = '\a'; break;
case 'b': char_val = '\b'; break;
case 'f': char_val = '\f'; break;
case 'v': char_val = '\v'; break;
case 'x': {
int h = 0;
while (isxdigit(lxpeek(lx))) {
char hc = lxget(lx);
h = h * 16 + (isdigit(hc) ? hc - '0' : tolower(hc) - 'a' + 10);
}
char_val = h;
break;
}
default: char_val = (unsigned char)esc; break;
}
} else if (lxpeek(lx) != '\'') {
char_val = (unsigned char)lxget(lx);
}
if (lxpeek(lx) != '\'') {
perror_at(lx, "unterminated or multi-character char literal");
}
lxget(lx); /* consume closing ' */
return (_T){TK_CHARLIT, char_val, NULL};
}
switch (c) {
case '(':
return (_T){TK_LPAREN, 0, lx_strdup_checked(lx,"(")};
case ')':
return (_T){TK_RPAREN, 0, lx_strdup_checked(lx,")")};
case '{':
return (_T){TK_LBRACE, 0, lx_strdup_checked(lx,"{")};
case '}':
return (_T){TK_RBRACE, 0, lx_strdup_checked(lx,"}")};
case ';':
return (_T){TK_SEMI, 0, lx_strdup_checked(lx,";")};
case '+':
if (lxpeek(lx) == '+') { lxget(lx); lx->col++; return (_T){TK_INC, 0, lx_strdup_checked(lx,"++")}; }
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_PLUS_EQ,0, lx_strdup_checked(lx,"+=")}; }
return (_T){TK_PLUS, 0, lx_strdup_checked(lx,"+")};
case '-':
if (lxpeek(lx) == '-') { lxget(lx); lx->col++; return (_T){TK_DEC, 0, lx_strdup_checked(lx,"--")}; }
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_MINUS_EQ,0, lx_strdup_checked(lx,"-=")}; }
return (_T){TK_MINUS, 0, lx_strdup_checked(lx,"-")};
case '*':
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_STAR_EQ, 0, lx_strdup_checked(lx,"*=")}; }
return (_T){TK_STAR, 0, lx_strdup_checked(lx,"*")};
case '/':
if (lxpeek(lx) == '=') { lxget(lx); lx->col++; return (_T){TK_SLASH_EQ,0, lx_strdup_checked(lx,"/=")}; }
return (_T){TK_SLASH, 0, lx_strdup_checked(lx,"/")};
case '&':
return (_T){TK_AMP, 0, lx_strdup_checked(lx,"&")};
case '|':
return (_T){TK_BAR, 0, lx_strdup_checked(lx,"|")};
case '^':
return (_T){TK_CARET, 0, lx_strdup_checked(lx,"^")};
case '%':
return (_T){TK_PERCENT, 0, lx_strdup_checked(lx,"%")};
case ',':
return (_T){TK_COMMA, 0, lx_strdup_checked(lx,",")};
case '\'':
return (_T){TK_SQUOTE, 0, lx_strdup_checked(lx,"'")};
case '"':
return (_T){TK_DQUOTE, 0, lx_strdup_checked(lx,"\"")};
case '[':
return (_T){TK_LBRACKET, 0, lx_strdup_checked(lx,"[")};
case ']':
return (_T){TK_RBRACKET, 0, lx_strdup_checked(lx,"]")};
case '?':
return (_T){TK_QUESTION, 0, lx_strdup_checked(lx,"?")};
case ':':
return (_T){TK_COLON, 0, lx_strdup_checked(lx,":")};
default:
return (_T){TK_INVALID, 0, NULL};
}
}
#undef sic
#undef sii
#undef siv
#undef sit
#endif
|
