use text_scanner::{ext::CScannerExt, Scanner};
use crate::{impl_lexer_from_scanner, ScanToken, ScannerExt, TokenSpan};
#[rustfmt::skip]
const KEYWORDS: [&str; 46] = [
"alignas", "alignof", "auto", "break", "case", "char", "const", "continue",
"default", "do", "double", "else", "enum", "extern", "float", "for", "goto",
"if", "inline", "int", "long", "register", "restrict", "return", "short",
"signed", "sizeof", "static", "struct", "switch", "typedef", "union",
"unsigned", "void", "volatile", "while", "_Alignas", "_Alignof", "_Atomic",
"_Bool", "_Complex", "_Generic", "_Imaginary", "_Noreturn", "_Static_assert",
"_Thread_local",
];
#[rustfmt::skip]
const KEYWORDS_MS: [&str; 21] = [
"__asm", "__based", "__cdecl", "__declspec", "__except", "__fastcall", "__finally",
"__inline", "__int16", "__int32", "__int64", "__int8", "__leave", "__restrict",
"__stdcall", "__try", "dllexport", "dllimport", "naked", "static_assert", "thread",
];
#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub enum CToken {
Space,
LineComment,
BlockComment,
Ident,
Keyword,
Char,
String,
Int,
Float,
Delim,
Punct,
Unknown,
}
impl ScanToken for CToken {
fn scan_token<'text>(scanner: &mut Scanner<'text>) -> Option<(Self, TokenSpan<'text>)> {
let (r, _s) = scanner.skip_whitespace();
if !r.is_empty() {
return Some((Self::Space, scanner.span(r)));
}
if let Ok((r, _s)) = scanner.scan_c_line_comment() {
return Some((Self::LineComment, scanner.span(r)));
} else if let Ok((r, _s)) = scanner.scan_c_block_comment() {
return Some((Self::BlockComment, scanner.span(r)));
}
if let Ok((r, ident)) = scanner.scan_c_identifier() {
let tok = if KEYWORDS.contains(&ident) || KEYWORDS_MS.contains(&ident) {
Self::Keyword
} else {
Self::Ident
};
return Some((tok, scanner.span(r)));
}
if let Ok((r, _s)) = scanner.scan_c_char() {
return Some((Self::Char, scanner.span(r)));
} else if let Ok((r, _s)) = scanner.scan_c_string() {
return Some((Self::String, scanner.span(r)));
}
if let Ok((r, _s)) = scanner.scan_c_float() {
return Some((Self::Float, scanner.span(r)));
} else if let Ok((r, _s)) = scanner
.scan_c_int_hex()
.or_else(|_| scanner.scan_c_int_oct())
.or_else(|_| scanner.scan_c_int_dec())
{
return Some((Self::Int, scanner.span(r)));
}
if let Ok((r, _c)) = scanner.accept_char_any(&['{', '}', '[', ']', '(', ')']) {
return Some((Self::Delim, scanner.span(r)));
}
let res = scanner.scan_with(|scanner| {
let (r, c) = scanner.next()?;
match c {
'=' => {
_ = scanner.accept_char_any(&['=', '>']);
}
'+' => {
_ = scanner.accept_char_any(&['+', '=']);
}
'-' => {
_ = scanner.accept_char_any(&['-', '=']);
}
'*' | '/' | '%' | '^' | '!' => {
_ = scanner.accept_char('=');
}
'&' => {
_ = scanner.accept_char_any(&['&', '=']);
}
'|' => {
_ = scanner.accept_char_any(&['|', '=']);
}
'<' => {
_ = scanner.accept_char('<');
_ = scanner.accept_char('=');
}
'>' => {
_ = scanner.accept_char('>');
_ = scanner.accept_char('=');
}
'.' => {
_ = scanner.scan_with(|scanner| {
scanner.accept_char('.')?;
scanner.accept_char('.')?;
Ok(())
});
}
'#' => {
_ = scanner.accept_char('#');
}
',' | ';' | ':' | '?' | '~' => {}
_ => return Err(scanner.ranged_text(r)),
}
Ok(())
});
if let Ok((r, _s)) = res {
return Some((Self::Punct, scanner.span(r)));
}
let (r, _c) = scanner.next().ok()?;
Some((Self::Unknown, scanner.span(r)))
}
}
#[derive(Clone, Debug)]
pub struct CLexer<'text> {
scanner: Scanner<'text>,
}
impl<'text> CLexer<'text> {
#[inline]
pub fn new(text: &'text str) -> Self {
Self {
scanner: Scanner::new(text),
}
}
}
impl_lexer_from_scanner!('text, CLexer<'text>, CToken, scanner);
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_c_lexer_spans() {
let input = include_str!("../../../text-scanner/src/ext/rust.rs");
let mut output = String::new();
let lexer = CLexer::new(input);
for (_tok, span) in lexer {
output.push_str(span.as_str());
}
assert_eq!(input, output);
}
}