use text_scanner::{ext::CssScannerExt, Scanner};
use crate::{impl_lexer_from_scanner, ScanToken, ScannerExt, TokenSpan};
const DELIMITERS: [char; 6] = ['{', '}', '[', ']', '(', ')'];
const PUNCTUATIONS: [char; 12] = [',', '.', ';', ':', '-', '+', '*', '=', '#', '!', '@', '%'];
#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub enum CssToken {
Space,
BlockComment,
Ident,
AtKeyword,
Hash,
String,
Number,
Punct,
Delim,
Unknown,
}
impl ScanToken for CssToken {
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, _c)) = scanner.scan_css_identifier() {
return Some((Self::Ident, scanner.span(r)));
} else if let Ok((r, _c)) = scanner.scan_css_at_keyword() {
return Some((Self::AtKeyword, scanner.span(r)));
} else if let Ok((r, _c)) = scanner.scan_css_hash() {
return Some((Self::Hash, scanner.span(r)));
}
if let Ok((r, _c)) = scanner.scan_css_number() {
return Some((Self::Number, scanner.span(r)));
} else if let Ok((r, _c)) = scanner.scan_css_string() {
return Some((Self::String, scanner.span(r)));
}
if let Ok((r, _c)) = scanner.accept_char_any(&DELIMITERS) {
return Some((Self::Delim, scanner.span(r)));
} else if let Ok((r, _c)) = scanner.accept_char_any(&PUNCTUATIONS) {
return Some((Self::Punct, scanner.span(r)));
}
if let Ok((r, _c)) = scanner.scan_css_block_comment() {
return Some((Self::BlockComment, scanner.span(r)));
}
let (r, _c) = scanner.next().ok()?;
Some((Self::Unknown, scanner.span(r)))
}
}
#[derive(Clone, Debug)]
pub struct CssLexer<'text> {
scanner: Scanner<'text>,
}
impl<'text> CssLexer<'text> {
#[inline]
pub fn new(text: &'text str) -> Self {
Self {
scanner: Scanner::new(text),
}
}
}
impl_lexer_from_scanner!('text, CssLexer<'text>, CssToken, scanner);
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_css_lexer_spans() {
let input = include_str!("../../../text-scanner/src/ext/rust.rs");
let mut output = String::new();
let lexer = CssLexer::new(input);
for (_tok, span) in lexer {
output.push_str(span.as_str());
}
assert_eq!(input, output);
}
}