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#include <stdlib.h>
#include <stdio.h>
#include "lex.h"
#include "arena.h"
#include "strio.h"
void lex_start(Lexer *l, const char *path) {
l->ofs = 0;
l->filename = str_dup(str_from_cstr(path), &l->arena);
FILE *f = fopen(path, "r/o");
if (!f) {
fprintf(stderr, "Couldn't open file %s\n", path);
exit(1);
}
if (read_all(f, &l->buf, &l->arena)) {
fprintf(stderr, "Couldn't read file %s\n", path);
fclose(f);
exit(1);
}
lex_next(l);
}
void lex_free(Lexer *l) {
arena_free(&l->arena);
}
Str lex_mask_str(Lexer *l, TokMask t) {
Str s = S("");
for (Token i = 0; i < TOK_MAX; i++) {
if (t & TMASK(i)) {
if (s.n > 0) str_cat(&s, S(" or "), &l->arena);
str_cat(&s, str_from_cstr(lex_tok_str[i]), &l->arena);
}
}
return s;
}
void lex_expect(Lexer *l, TokMask t) {
lex_next(l);
lex_expected(l, t);
}
void lex_expect_not(Lexer *l, TokMask t) {
lex_next(l);
lex_expected_not(l, t);
}
void lex_expected(Lexer *l, TokMask t) {
if (!(TMASK(l->tok) & t)) {
lex_error(l, LE_ERROR, str_fmt(&l->arena, "expected %S but got %s", lex_mask_str(l, t), lex_tok_str[l->tok]));
}
}
void lex_expected_not(Lexer *l, TokMask t) {
if (TMASK(l->tok) & t) {
lex_error(l, LE_ERROR, str_fmt(&l->arena, "unexpected %s", lex_tok_str[l->tok]));
}
}
/* should only be called in the event of errors, so probably not
* much of an issue that this has to scan the whole file */
void lex_pos(Lexer *l, int ofs, int *line, int *col) {
int ln = 0, c = 0;
for (int i = 0; i < ofs; i++) {
if (l->buf.s[i] == '\n') {
ln++;
c = 0;
} else {
c++;
if (l->buf.s[i] == '\t') {
c += (unsigned)-c & 7;
}
}
}
*line = ln;
*col = c;
}
void lex_error(Lexer *l, LexErr e, Str msg) {
lex_error_at(l, l->pos, e, msg);
}
void lex_err_color(LexErr e) {
fprintf(stderr, "%s", e == LE_NONE ? "\x1b[0m" : (e == LE_ERROR ? "\x1b[1;31m" : "\x1b[1;33m"));
}
void lex_error_at(Lexer *l, LexSpan pos, LexErr e, Str msg) {
int line, col;
lex_pos(l, pos.ofs, &line, &col);
fprintf(stderr, "\x1b[1m%.*s:%d:%d:\x1b[0m ", (int)l->filename.n, l->filename.s, line + 1, col + 1);
lex_err_color(e);
if (e != LE_NONE) fprintf(stderr, "%s", e == LE_ERROR ? "error" : "warn");
lex_err_color(LE_NONE);
fprintf(stderr, ": %.*s\n", (int)msg.n, msg.s);
{
int ofs = pos.ofs;
int line_start = ofs;
while (line_start > 0 && l->buf.s[line_start - 1] != '\n') line_start--;
int line_end = line_start;
while (line_end < l->buf.n && l->buf.s[line_end] != '\n') line_end++;
lex_err_color(e);
fprintf(stderr, "%.*s\n", line_end - line_start, &l->buf.s[line_start]);
for (int i = 0; i < col; i++) fputc(' ', stderr);
fputc('^', stderr);
for (int i = ofs + 1; i < ofs + pos.n && i < line_end; i++) fputc('~', stderr);
lex_err_color(LE_NONE);
fputc('\n', stderr);
}
if (e == LE_ERROR) {
exit(1);
}
}
static inline int is_digit(int c) {
return c >= '0' && c <= '9';
}
static inline int is_ident_first_char(int c) {
return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_';
}
static inline int is_ident_next_char(int c) {
return is_ident_first_char(c) || is_digit(c);
}
Token ident_to_keyword(Str ident) {
/* evil & stupid hack to avoid keeping a separate table of keywords */
for (Token t = 0; t < TOK_MAX; t++) {
if (str_eql(str_from_cstr(lex_tok_str[t]), ident)) {
return t;
}
}
return TOK_IDENT;
}
#define T(t) (l->tok = t)
void lex_next(Lexer *l) {
recurse:
int i = l->ofs;
while (i < l->buf.n && is_space(l->buf.s[i])) {
i++;
}
if (str_starts(str_skip(l->buf, i), S("/*"))) {
Str f = str_find(str_skip(l->buf, i), S("*/"));
l->ofs = (f.s - l->buf.s) + 2;
goto recurse;
}
if (str_starts(str_skip(l->buf, i), S("//"))) {
Str f = str_findc(str_skip(l->buf, i), '\n');
l->ofs = f.s - l->buf.s;
goto recurse;
}
int start_ofs = i;
l->ident = (Str) { &l->buf.s[start_ofs], 0 };
l->pos = (LexSpan) { start_ofs, 0 };
if (i >= l->buf.n) {
l->tok = TOK_EOF;
return;
}
char c = l->buf.s[i++];
l->tok = TOK_MAX;
if (is_ident_first_char(c)) {
T(TOK_IDENT);
while (i < l->buf.n && is_ident_next_char(l->buf.s[i])) i++;
} else if (is_digit(c)) {
T(TOK_LIT_NUM);
while (i < l->buf.n && (is_digit(l->buf.s[i]) || l->buf.s[i] == '.' || l->buf.s[i] == 'e')) i++;
} else {
switch (c) {
#define X(a,b) case b: T(a); break;
LEX_TOK_CHAR_LIST
#undef X
case '\'':
T(TOK_LIT_CHAR);
if (i < l->buf.n && l->buf.s[i] == '\\') i += 2;
else i++;
if (i >= l->buf.n) lex_error(l, LE_ERROR, S("unterminated character literal"));
if (l->buf.s[i] != '\'') lex_error(l, LE_ERROR, S("overlong character literal"));
i++;
break;
case '"':
T(TOK_LIT_STR);
for (;;) {
if (i >= l->buf.n) {
lex_error(l, LE_ERROR, S("unterminated string literal"));
}
if (l->buf.s[i] == '\\') {
i += 2;
continue;
}
if (l->buf.s[i++] == '"') break;
}
break;
case '<':
switch (l->buf.s[i]) {
case '=': T(TOK_LTE); i++; break;
case '>': T(TOK_NEQ); i++; break;
case '<': T(TOK_SHL); i++; break;
default: T(TOK_LES); break;
}
break;
case '>':
switch (l->buf.s[i]) {
case '=': T(TOK_GTE); i++; break;
case '>': T(TOK_SHR); i++; break;
default: T(TOK_GTR); break;
}
break;
case ':':
switch (l->buf.s[i]) {
case '=': T(TOK_ASSIGN); i++; break;
case '>': T(TOK_SHR); break;
}
break;
}
}
if (l->tok == TOK_MAX) {
lex_error(l, LE_ERROR, S("parse error"));
}
l->ident.n = i - start_ofs;
l->pos.n = i - start_ofs;
l->ofs = i;
if (l->tok == TOK_IDENT) {
l->tok = ident_to_keyword(l->ident);
}
}
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