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// src/lexer.c
#define CMMM__RS274NGC__LEXEME__STRIP_VENDOR
#define CMMM__RS274NGC__LEXER__STRIP_VENDOR
#include "cmmm/rs274ngc/lexer.h"
#include <regex.h>
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <ctype.h>
#define X(SYM, REG, ...) \
[RS274NGC__LEXEME__KIND__##SYM - RS274NGC__LEXEME__REGEX_OFFSET] = "^(" REG ")",
static const char *lexeme_regex_strings[RS274NGC__LEXEME__REGEX_COUNT] = {
RS274NGC__LEXEME__KINDS ()
};
#undef X
static regex_t lexeme_regexes[RS274NGC__LEXEME__REGEX_COUNT];
static void
print_regex_error (const regex_t *comp, const char *regex, int errcode)
{
size_t length = regerror (errcode, comp, NULL, 0);
char *buffer = malloc (length);
regerror (errcode, comp, buffer, length);
fprintf (stderr, "error: regcomp (\"%s\"): %s\n", regex, buffer);
free (buffer);
}
static void __attribute__((constructor))
compile_regexes (void)
{
bool errored = false;
for (int i = 0; i < RS274NGC__LEXEME__REGEX_COUNT; ++i) {
regex_t *compiled = &lexeme_regexes[i];
const char *pattern = lexeme_regex_strings[i];
int errcode = regcomp (compiled, pattern, REG_EXTENDED);
if (errcode) {
print_regex_error (compiled, pattern, errcode);
errored = true;
}
}
if (errored)
exit (EXIT_FAILURE);
}
struct rs274ngc__lexer
rs274ngc__lexer__from_string_view (struct cmmm__string_view sv,
const char *filename)
{
struct rs274ngc__lexer lexer = {
.sv = sv,
.cursor = sv.begin,
.filename = filename,
};
rs274ngc__lexer__next_lexeme (&lexer);
return lexer;
}
static void
skip_whitespace (struct rs274ngc__lexer *lexer)
{
while (lexer->cursor < lexer->sv.end && (*lexer->cursor == ' ' ||
*lexer->cursor == '\t'))
lexer->cursor += 1;
}
void
rs274ngc__lexer__next_lexeme (struct rs274ngc__lexer *lexer)
{
skip_whitespace (lexer);
lexer->lexeme = (struct rs274ngc__lexeme) { .sv.begin = lexer->cursor };
if (lexer->cursor >= lexer->sv.end) {
lexer->lexeme.kind = RS274NGC__LEXEME__KIND__END_OF_FILE;
lexer->lexeme.sv.end = lexer->sv.end;
return;
}
if (*lexer->cursor == '\r') {
if (*lexer->cursor == '\n')
lexer->cursor += 1;
lexer->lexeme.kind = RS274NGC__LEXEME__KIND__END_OF_LINE;
lexer->lexeme.sv.end = ++lexer->cursor;
return;
}
if (*lexer->cursor == '\n') {
lexer->lexeme.kind = RS274NGC__LEXEME__KIND__END_OF_LINE;
lexer->lexeme.sv.end = ++lexer->cursor;
return;
}
regmatch_t regmatch;
int longest_matching_regex = RS274NGC__LEXEME__REGEX_COUNT;
int longest_matching_regex_length = 0;
for (int i = 0; i < RS274NGC__LEXEME__REGEX_COUNT; ++i) {
if (regexec (&lexeme_regexes[i], lexer->cursor, 1, ®match, 0)) continue;
if (regmatch.rm_eo <= longest_matching_regex_length) continue;
longest_matching_regex_length = regmatch.rm_eo;
longest_matching_regex = i;
// HACK(cmmm): choose first match
#ifdef RS274NGC__LEXER__FIRST_MATCH
break;
#endif
}
if (longest_matching_regex != RS274NGC__LEXEME__REGEX_COUNT) {
lexer->lexeme.kind = longest_matching_regex + RS274NGC__LEXEME__REGEX_OFFSET;
lexer->lexeme.sv.end = lexer->cursor += longest_matching_regex_length;
// HACK(cmmm): right trim lexemes
#ifdef RS274NGC__LEXER__TRIM
while (lexer->lexeme.sv.end > lexer->lexeme.sv.begin &&
(lexer->lexeme.sv.end[-1] == ' ' ||
lexer->lexeme.sv.end[-1] == '\t')) {
lexer->lexeme.sv.end -= 1;
}
#endif
switch (lexer->lexeme.kind) {
#ifdef RS274NGC__LEXER__FILTER_COMMENTS
case RS274NGC__LEXEME__KIND__COMMENT:
return rs274ngc__lexer__next_lexeme (lexer);
#endif
default: return;
}
}
// INVALID
lexer->lexeme.sv.end = ++lexer->cursor;
}
// src/lexer.c ends here
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