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#include "lex.h"
#include <stdbool.h>
#include <string.h>
#include "mem.h"
inline bool is_space_char(char input) {
return input == '\t' || input == ' ' || input == '\n' || input == '\r';
}
inline bool is_int_char(char input) {
return '0' <= input && input <= '9';
}
/* The number of bytes that should be read to read an integer */
unsigned char lex_int_length(char *input) {
unsigned char n = 0;
while (is_int_char(*input++)) n++;
return n;
}
inline bool is_name_char(char input) {
return (('A' <= input && input <= 'Z') ||
('a' <= input && input <= 'z') ||
input == '_');
}
/* The number of bytes that should be read to read a name */
unsigned char lex_name_length(char *input) {
unsigned char n = 0;
while (is_name_char(*input++)) n++;
return n;
}
struct token_list *lex(struct token_list *list, char *input) {
struct token_list *first_list;
bool create_new_token;
while (*input && is_space_char(*input)) input++;
if (*input == 0) {
return list;
}
if (list) {
first_list = list;
while (list->rest) list = list->rest;
list->rest = my_calloc(1, sizeof(struct token_list));
list = list->rest;
} else {
first_list = list = my_calloc(1, sizeof(struct token_list));
}
create_new_token = 1;
while (*input) {
list->elem.var = NULL;
switch (*input) {
case ';': list->elem.kind = TOKEN_SEMICOLON; break;
case ':': list->elem.kind = TOKEN_COLON; break;
case '(': list->elem.kind = TOKEN_OPEN_P; break;
case ')': list->elem.kind = TOKEN_CLOSE_P; break;
case '[': list->elem.kind = TOKEN_OPEN_SQ; break;
case ']': list->elem.kind = TOKEN_CLOSE_SQ; break;
case '=': list->elem.kind = TOKEN_EQUALS; break;
case ',': list->elem.kind = TOKEN_COMMA; break;
default:
if (input[0] == '/' && input[1] == '/') {
while (input && input[0] != '\n') input++;
break;
}
if (input[0] == 'c' && input[1] == 'o' && input[2] == 'd' &&
input[3] == 'e' && is_space_char(input[4])) {
list->elem.kind = TOKEN_CODE;
input += 4;
break;
}
if (input[0] == 'i' && input[1] == 'm' && input[2] == 'p' &&
input[3] == 'o' && input[4] == 'r' &&
input[5] == 't' && is_space_char(input[6])) {
list->elem.kind = TOKEN_IMPORT;
input += 6;
break;
}
if (is_int_char(*input)) {
char *s;
unsigned char len = lex_int_length(input);
s = my_calloc(1, len + 1);
list->elem.kind = TOKEN_INT;
list->elem.var = my_calloc(1, sizeof(int));
strncpy(s, input, len);
*((int*) list->elem.var) = atoi(s);
my_free(s);
input += len - 1;
} else if (is_name_char(*input)) {
unsigned char len = lex_name_length(input);
list->elem.kind = TOKEN_NAME;
list->elem.var = my_calloc(1, len + 1);
strncpy(list->elem.var, input, len);
input += len - 1;
} else if (is_space_char(*input)) {
create_new_token = 0;
} else {
free_token_list(first_list);
my_free(first_list);
return NULL;
}
}
do input++; while (*input && is_space_char(*input));
if (*input && create_new_token) {
list->rest = my_calloc(1, sizeof(struct token_list));
list = list->rest;
}
}
return first_list;
}
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