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use std::ops::RangeInclusive;
use winnow::combinator::alt;
use winnow::combinator::eof;
use winnow::combinator::opt;
use winnow::combinator::repeat;
use winnow::combinator::terminated;
use winnow::prelude::*;
use winnow::token::one_of;
use winnow::token::take_while;
use crate::parser::prelude::*;
pub(crate) unsafe fn from_utf8_unchecked<'b>(
bytes: &'b [u8],
safety_justification: &'static str,
) -> &'b str {
if cfg!(debug_assertions) {
// Catch problems more quickly when testing
std::str::from_utf8(bytes).expect(safety_justification)
} else {
std::str::from_utf8_unchecked(bytes)
}
}
// wschar = ( %x20 / ; Space
// %x09 ) ; Horizontal tab
pub(crate) const WSCHAR: (u8, u8) = (b' ', b'\t');
// ws = *wschar
pub(crate) fn ws<'i>(input: &mut Input<'i>) -> PResult<&'i str> {
take_while(0.., WSCHAR)
.map(|b| unsafe { from_utf8_unchecked(b, "`is_wschar` filters out on-ASCII") })
.parse_next(input)
}
// non-ascii = %x80-D7FF / %xE000-10FFFF
// - ASCII is 0xxxxxxx
// - First byte for UTF-8 is 11xxxxxx
// - Subsequent UTF-8 bytes are 10xxxxxx
pub(crate) const NON_ASCII: RangeInclusive<u8> = 0x80..=0xff;
// non-eol = %x09 / %x20-7E / non-ascii
pub(crate) const NON_EOL: (u8, RangeInclusive<u8>, RangeInclusive<u8>) =
(0x09, 0x20..=0x7E, NON_ASCII);
// comment-start-symbol = %x23 ; #
pub(crate) const COMMENT_START_SYMBOL: u8 = b'#';
// comment = comment-start-symbol *non-eol
pub(crate) fn comment<'i>(input: &mut Input<'i>) -> PResult<&'i [u8]> {
(COMMENT_START_SYMBOL, take_while(0.., NON_EOL))
.recognize()
.parse_next(input)
}
// newline = ( %x0A / ; LF
// %x0D.0A ) ; CRLF
pub(crate) fn newline(input: &mut Input<'_>) -> PResult<u8> {
alt((
one_of(LF).value(b'\n'),
(one_of(CR), one_of(LF)).value(b'\n'),
))
.parse_next(input)
}
pub(crate) const LF: u8 = b'\n';
pub(crate) const CR: u8 = b'\r';
// ws-newline = *( wschar / newline )
pub(crate) fn ws_newline<'i>(input: &mut Input<'i>) -> PResult<&'i str> {
repeat(
0..,
alt((newline.value(&b"\n"[..]), take_while(1.., WSCHAR))),
)
.map(|()| ())
.recognize()
.map(|b| unsafe { from_utf8_unchecked(b, "`is_wschar` and `newline` filters out on-ASCII") })
.parse_next(input)
}
// ws-newlines = newline *( wschar / newline )
pub(crate) fn ws_newlines<'i>(input: &mut Input<'i>) -> PResult<&'i str> {
(newline, ws_newline)
.recognize()
.map(|b| unsafe {
from_utf8_unchecked(b, "`is_wschar` and `newline` filters out on-ASCII")
})
.parse_next(input)
}
// note: this rule is not present in the original grammar
// ws-comment-newline = *( ws-newline-nonempty / comment )
pub(crate) fn ws_comment_newline<'i>(input: &mut Input<'i>) -> PResult<&'i [u8]> {
repeat(
0..,
alt((
repeat(
1..,
alt((take_while(1.., WSCHAR), newline.value(&b"\n"[..]))),
)
.map(|()| ()),
comment.value(()),
)),
)
.map(|()| ())
.recognize()
.parse_next(input)
}
// note: this rule is not present in the original grammar
// line-ending = newline / eof
pub(crate) fn line_ending<'i>(input: &mut Input<'i>) -> PResult<&'i str> {
alt((newline.value("\n"), eof.value(""))).parse_next(input)
}
// note: this rule is not present in the original grammar
// line-trailing = ws [comment] skip-line-ending
pub(crate) fn line_trailing(input: &mut Input<'_>) -> PResult<std::ops::Range<usize>> {
terminated((ws, opt(comment)).span(), line_ending).parse_next(input)
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn trivia() {
let inputs = [
"",
r#" "#,
r#"
"#,
r#"
# comment
# comment2
"#,
r#"
"#,
r#"# comment
# comment2
"#,
];
for input in inputs {
dbg!(input);
let parsed = ws_comment_newline.parse(new_input(input));
assert!(parsed.is_ok(), "{:?}", parsed);
let parsed = parsed.unwrap();
assert_eq!(parsed, input.as_bytes());
}
}
}
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