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
|
#include "lexer.h"
#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
void free_tokens(struct TOKEN *token) {
for (; token;) {
struct TOKEN *old = token;
token = token->next;
free(old);
}
}
int is_special_char(char c) {
if (!isprint(c)) {
return 1;
}
if (isspace(c)) {
return 1;
}
if (isalnum(c)) {
return 0;
}
return !(('>' != c && '|' != c && '&' != c && '=' != c));
}
int parse_chars(struct sv *code_ptr, struct TOKEN *cur) {
struct sv code = *code_ptr;
if (sv_partial_eq(code, C_TO_SV("\""))) {
sv_take(code, &code, 1);
cur->type = TOKEN_CHARS;
cur->string_rep = sv_split_delim(code, &code, '"');
*code_ptr = code;
return 1;
}
if (is_special_char(sv_peek(code))) {
return 0;
}
cur->type = TOKEN_CHARS;
cur->string_rep = sv_split_function(code, &code, is_special_char);
*code_ptr = code;
return 1;
}
// Operands such as: &, &&, |, || etc
// Is operands the right word?
int parse_operand(struct sv *code_ptr, struct TOKEN *cur) {
struct sv code = *code_ptr;
#define TRY_PARSE_STRING(_s, _token) \
if (sv_partial_eq(code, C_TO_SV(_s))) { \
cur->type = _token; \
cur->string_rep = sv_take(code, &code, strlen(_s)); \
goto complete_return; \
}
TRY_PARSE_STRING("&&", TOKEN_AND);
TRY_PARSE_STRING("||", TOKEN_NOT);
TRY_PARSE_STRING(">>", TOKEN_STREAM_APPEND);
TRY_PARSE_STRING(">", TOKEN_STREAM);
TRY_PARSE_STRING("|", TOKEN_PIPE);
TRY_PARSE_STRING("&", TOKEN_BACKGROUND);
TRY_PARSE_STRING("=", TOKEN_EQUAL);
TRY_PARSE_STRING("\n", TOKEN_NEWLINE);
// Failed to parse
return 0;
complete_return:
*code_ptr = code;
return 1;
}
void skip_whitespace_and_comment(struct sv *s) {
struct sv start;
do {
start = *s;
*s = sv_skip_chars(*s, " \t\r");
if (!sv_partial_eq(*s, C_TO_SV("#"))) {
return;
}
(void)sv_split_delim(*s, s, '\n');
} while (start.length != s->length);
}
struct TOKEN *lex(struct sv code) {
struct TOKEN *head = NULL;
struct TOKEN *prev = NULL;
for (; !sv_isempty(code);) {
skip_whitespace_and_comment(&code);
if (sv_isempty(code)) {
break;
}
struct TOKEN *cur = malloc(sizeof(struct TOKEN));
cur->next = NULL;
if (prev) {
prev->next = cur;
}
if (parse_chars(&code, cur)) {
} else if (parse_operand(&code, cur)) {
} else {
free(cur);
assert(0 && "Unknown token");
}
if (!head) {
head = cur;
}
prev = cur;
}
return head;
}
|
