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#include "lexer.h"
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include "utils.h"
#include <assert.h>
Lexer *Lexer_new(char *filename, char *src, i64 len)
{
Lexer *self = calloc(1, sizeof(Lexer));
self->src = src;
self->len = len;
self->filename = filename;
return self;
}
Lexer *Lexer_new_open_file(char *filename)
{
FILE *fp = fopen(filename, "r");
fseek(fp, 0, SEEK_END);
i64 source_len = ftell(fp);
fseek(fp, 0, SEEK_SET);
char *source = malloc(source_len + 1);
fread(source, source_len, 1, fp);
source[source_len] = 0;
fclose(fp);
Lexer *self = calloc(1, sizeof(Lexer));
self->filename = filename;
self->src = source;
self->len = source_len;
return self;
}
static Location Lexer_loc(Lexer *lexer)
{
Location loc = {0};
loc.filename = lexer->filename;
loc.line = lexer->line;
loc.col = lexer->col;
return loc;
}
static void Lexer_skip_whitespace(Lexer *lexer)
{
while (lexer->pos < lexer->len && isspace(lexer->src[lexer->pos])) {
if (lexer->src[lexer->pos] == '\n') {
lexer->line++;
lexer->col = 0;
} else {
lexer->col++;
}
lexer->pos++;
}
}
bool Lexer_has_more(Lexer *lexer)
{
Lexer_skip_whitespace(lexer);
return lexer->pos < lexer->len;
}
static bool Lexer_starts_with(Lexer *lexer, char *str)
{
i64 len = strlen(str);
if (lexer->len - lexer->pos < len)
return false;
for (i64 i = 0; i < len; i++)
if (lexer->src[lexer->pos + i] != str[i])
return false;
i64 end_pos = lexer->pos + len;
if (end_pos == lexer->len)
return true;
char end_char = lexer->src[end_pos];
return !(isdigit(end_char) || isalpha(end_char) || end_char == '_');
}
static void advance(Lexer *lexer, i64 amount)
{
lexer->pos += amount;
lexer->col += amount;
}
static char peek(Lexer *lexer, int amount)
{
if (lexer->pos + amount >= lexer->len)
return '\0';
return lexer->src[lexer->pos + amount];
}
static Token Lexer_make_token(Lexer *lexer, TokenType type, int inc_amount)
{
Token token = {0};
token.type = type;
token.loc = Lexer_loc(lexer);
advance(lexer, inc_amount);
return token;
}
static char get_escaped(char c) {
switch (c)
{
case 'n': return '\n';
case 'r': return '\r';
case 't': return '\t';
case '\\': return '\\';
case '0': return '\0';
}
assert(false && "Unknown escape sequence");
}
Token Lexer_next(Lexer *lexer)
{
while (lexer->pos < lexer->len) {
switch (lexer->src[lexer->pos])
{
case ' ': case '\t': case '\r': advance(lexer, 1); continue;
case '\n': lexer->line++; lexer->col = 0; lexer->pos++; continue;
case '(': return Lexer_make_token(lexer, TOKEN_OPEN_PAREN, 1);
case ')': return Lexer_make_token(lexer, TOKEN_CLOSE_PAREN, 1);
case '{': return Lexer_make_token(lexer, TOKEN_OPEN_BRACE, 1);
case '}': return Lexer_make_token(lexer, TOKEN_CLOSE_BRACE, 1);
case '[': return Lexer_make_token(lexer, TOKEN_OPEN_BRACKET, 1);
case ']': return Lexer_make_token(lexer, TOKEN_CLOSE_BRACKET, 1);
case ';': return Lexer_make_token(lexer, TOKEN_SEMICOLON, 1);
case ':': return Lexer_make_token(lexer, TOKEN_COLON, 1);
case '~': return Lexer_make_token(lexer, TOKEN_TILDE, 1);
case '?': return Lexer_make_token(lexer, TOKEN_QUESTION, 1);
case '.': return Lexer_make_token(lexer, TOKEN_DOT, 1);
case ',': return Lexer_make_token(lexer, TOKEN_COMMA, 1);
case '*': return Lexer_make_token(lexer, TOKEN_STAR, 1);
case '%': return Lexer_make_token(lexer, TOKEN_PERCENT, 1);
case '&': {
if (peek(lexer, 1) == '&')
return Lexer_make_token(lexer, TOKEN_AND, 2);
return Lexer_make_token(lexer, TOKEN_AMPERSAND, 1);
}
case '!': {
if (peek(lexer, 1) == '=')
return Lexer_make_token(lexer, TOKEN_NEQ, 2);
return Lexer_make_token(lexer, TOKEN_EXCLAMATION, 1);
}
case '<': {
if (peek(lexer, 1) == '=')
return Lexer_make_token(lexer, TOKEN_LEQ, 2);
return Lexer_make_token(lexer, TOKEN_LT, 1);
}
case '>': {
if (peek(lexer, 1) == '=')
return Lexer_make_token(lexer, TOKEN_GEQ, 2);
return Lexer_make_token(lexer, TOKEN_GT, 1);
}
case '=': {
if (peek(lexer, 1) == '=')
return Lexer_make_token(lexer, TOKEN_EQ, 2);
return Lexer_make_token(lexer, TOKEN_ASSIGN, 1);
}
case '|': {
if (peek(lexer, 1) == '|')
return Lexer_make_token(lexer, TOKEN_OR, 2);
return Lexer_make_token(lexer, TOKEN_BAR, 1);
}
case '+': {
if (peek(lexer, 1) == '+')
return Lexer_make_token(lexer, TOKEN_PLUSPLUS, 2);
if (peek(lexer, 1) == '=')
return Lexer_make_token(lexer, TOKEN_PLUSEQUALS, 2);
return Lexer_make_token(lexer, TOKEN_PLUS, 1);
}
case '-': {
if (peek(lexer, 1) == '-')
return Lexer_make_token(lexer, TOKEN_MINUSMINUS, 2);
if (peek(lexer, 1) == '=')
return Lexer_make_token(lexer, TOKEN_MINUSEQUALS, 2);
return Lexer_make_token(lexer, TOKEN_MINUS, 1);
}
case '/': {
if (peek(lexer, 1) == '/') {
lexer->pos += 2; // skip the '//'
while (lexer->pos < lexer->len && lexer->src[lexer->pos] != '\n')
lexer->pos++;
continue;
}
return Lexer_make_token(lexer, TOKEN_SLASH, 1);
}
default: {
// Handle keywords explicitly
#define LEX_KEYWORD(token_type, str) if (Lexer_starts_with(lexer, str)) return Lexer_make_token(lexer, token_type, strlen(str));
ENUM_KEYWORDS(LEX_KEYWORD)
#undef LEX_KEYWORD
if (isdigit(lexer->src[lexer->pos])) {
// TODO: Parse hex and octal numbers
i64 pos = lexer->pos;
while (pos < lexer->len && isdigit(lexer->src[pos]))
pos++;
Token token = Token_from_int(atoi(lexer->src + lexer->pos), Lexer_loc(lexer));
advance(lexer, pos - lexer->pos);
return token;
}
if (isalpha(lexer->src[lexer->pos]) || lexer->src[lexer->pos] == '_') {
i64 pos = lexer->pos;
while (pos < lexer->len && (isalnum(lexer->src[pos]) || lexer->src[pos] == '_'))
pos++;
int str_len = pos - lexer->pos;
char *str = calloc(str_len + 1, 1);
strncpy(str, lexer->src + lexer->pos, str_len);
Token token = Token_from_identifier(str, Lexer_loc(lexer));
advance(lexer, str_len);
return token;
}
// TODO: Handle escapes
if (lexer->src[lexer->pos] == '"') {
i64 pos = lexer->pos + 1;
while (pos < lexer->len && lexer->src[pos] != '"')
pos++;
if (pos == lexer->len) {
die_location(Lexer_loc(lexer), ": ERROR: Reached end-of-file while parsing string literal beginning here.\n");
}
// Careful with indexing here, because we want to skip opening and closing quotes
char *str = calloc(pos - lexer->pos, 1);
strncpy(str, lexer->src + lexer->pos + 1, pos - lexer->pos - 1);
Token token = Token_from_string(str, Lexer_loc(lexer));
advance(lexer, pos - lexer->pos + 1);
return token;
}
if (lexer->src[lexer->pos] == '\'') {
i64 pos = lexer->pos + 1;
// TODO: Handle malformed / incomplete literals
// TODO: Handle escapes
char c = lexer->src[pos];
if (c == '\\') {
pos++;
c = get_escaped(lexer->src[pos]);
}
Token token = Token_from_char(c, Lexer_loc(lexer));
advance(lexer, pos - lexer->pos + 2);
return token;
}
die_location(Lexer_loc(lexer), ": ERROR: Unexpected character '%c'\n", lexer->src[lexer->pos]);
advance(lexer, 1);
}
}
}
return Token_from_type(TOKEN_EOF, Lexer_loc(lexer));
}
Token Lexer_peek(Lexer *lexer)
{
i64 pos = lexer->pos;
i64 col = lexer->col;
i64 line = lexer->line;
Token token = Lexer_next(lexer);
lexer->pos = pos;
lexer->col = col;
lexer->line = line;
return token;
}
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