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use crate::scanner::*;
use crate::token::{Token, TokenKind};
pub struct CssScanner;
fn at(b: &[u8], i: usize) -> u8 {
if i < b.len() { b[i] } else { 0 }
}
impl Scanner for CssScanner {
fn scan(&self, code: &str) -> Vec<Token> {
let b = code.as_bytes();
let mut tokens = Vec::new();
let mut i = 0;
let mut in_block = false; // inside { ... }
while i < b.len() {
let c = b[i];
if c == b' ' || c == b'\t' || c == b'\n' || c == b'\r' {
i += 1;
continue;
}
// Comments
if let Some(end) = scan_block_comment(b, i) {
tokens.push(Token {
kind: TokenKind::Comment,
start: i,
end,
});
i = end;
continue;
}
// Strings
if c == b'"'
&& let Some(end) = scan_double_string(b, i)
{
tokens.push(Token {
kind: TokenKind::String,
start: i,
end,
});
i = end;
continue;
}
if c == b'\''
&& let Some(end) = scan_single_string(b, i)
{
tokens.push(Token {
kind: TokenKind::String,
start: i,
end,
});
i = end;
continue;
}
// @ rules
if c == b'@' {
let start = i;
i += 1;
while i < b.len() && (b[i].is_ascii_alphanumeric() || b[i] == b'-') {
i += 1;
}
tokens.push(Token {
kind: TokenKind::Keyword,
start,
end: i,
});
continue;
}
// Track block depth
if c == b'{' {
in_block = true;
tokens.push(Token {
kind: TokenKind::Punctuation,
start: i,
end: i + 1,
});
i += 1;
continue;
}
if c == b'}' {
in_block = false;
tokens.push(Token {
kind: TokenKind::Punctuation,
start: i,
end: i + 1,
});
i += 1;
continue;
}
// Inside block: property: value;
if in_block {
// Property name (before colon)
if c.is_ascii_alphabetic() || c == b'-' || c == b'_' {
let start = i;
while i < b.len()
&& (b[i].is_ascii_alphanumeric() || b[i] == b'-' || b[i] == b'_')
{
i += 1;
}
let after = skip_whitespace_no_newline(b, i);
if at(b, after) == b':' {
tokens.push(Token {
kind: TokenKind::Property,
start,
end: i,
});
} else {
tokens.push(Token {
kind: TokenKind::Plain,
start,
end: i,
});
}
continue;
}
if c == b':' {
tokens.push(Token {
kind: TokenKind::Punctuation,
start: i,
end: i + 1,
});
i += 1;
continue;
}
// Numbers with units
if (c.is_ascii_digit() || (c == b'.' && at(b, i + 1).is_ascii_digit()))
&& let Some(end) = scan_number(b, i)
{
let mut e = end;
// Consume CSS units
while e < b.len() && (b[e].is_ascii_alphabetic() || b[e] == b'%') {
e += 1;
}
tokens.push(Token {
kind: TokenKind::Number,
start: i,
end: e,
});
i = e;
continue;
}
// Hash colors
if c == b'#' {
let start = i;
i += 1;
while i < b.len() && b[i].is_ascii_hexdigit() {
i += 1;
}
tokens.push(Token {
kind: TokenKind::Number,
start,
end: i,
});
continue;
}
// Function calls in values (rgb, calc, etc)
if c.is_ascii_alphabetic() || c == b'-' {
let start = i;
while i < b.len()
&& (b[i].is_ascii_alphanumeric() || b[i] == b'-' || b[i] == b'_')
{
i += 1;
}
if at(b, i) == b'(' {
tokens.push(Token {
kind: TokenKind::Function,
start,
end: i,
});
} else {
tokens.push(Token {
kind: TokenKind::Plain,
start,
end: i,
});
}
continue;
}
} else {
// Selectors (outside blocks)
if c == b'.' || c == b'#' || c == b'*' || c == b':' || c == b'[' {
let start = i;
// Just consume selector chars
if c == b'.' || c == b'#' {
i += 1;
while i < b.len()
&& (b[i].is_ascii_alphanumeric() || b[i] == b'-' || b[i] == b'_')
{
i += 1;
}
} else if c == b':' {
i += 1;
if at(b, i) == b':' {
i += 1;
}
while i < b.len() && (b[i].is_ascii_alphanumeric() || b[i] == b'-') {
i += 1;
}
} else {
i += 1;
}
tokens.push(Token {
kind: TokenKind::Keyword,
start,
end: i,
});
continue;
}
// Tag selectors
if c.is_ascii_alphabetic() {
let start = i;
while i < b.len() && (b[i].is_ascii_alphanumeric() || b[i] == b'-') {
i += 1;
}
tokens.push(Token {
kind: TokenKind::Keyword,
start,
end: i,
});
continue;
}
}
// Punctuation
if let Some(end) = scan_punctuation(b, i) {
tokens.push(Token {
kind: TokenKind::Punctuation,
start: i,
end,
});
i = end;
continue;
}
i += 1;
}
tokens
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::token::render;
fn hl(code: &str) -> String {
let tokens = CssScanner.scan(code);
render(code, &tokens)
}
#[test]
fn selector_and_property() {
let out = hl("body { color: red; }");
assert!(out.contains("tok-keyword")); // selector
assert!(out.contains("tok-property")); // color
}
#[test]
fn at_rule() {
let out = hl("@media screen");
assert!(out.contains("tok-keyword"));
}
#[test]
fn comment() {
let out = hl("/* comment */");
assert!(out.contains("tok-comment"));
}
#[test]
fn number_with_unit() {
let out = hl("body { width: 100px; }");
assert!(out.contains("tok-number"));
}
#[test]
fn class_selector() {
let out = hl(".foo { }");
assert!(out.contains("tok-keyword"));
}
}