406 lines
13 KiB
Rust
406 lines
13 KiB
Rust
use nom::branch::alt;
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use nom::bytes::complete::tag;
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use nom::character::complete;
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use nom::character::complete::{anychar, line_ending, not_line_ending, tab};
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use nom::combinator::{fail, not, opt};
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use nom::error::ErrorKind;
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use nom::multi::{many1, separated_list1};
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use nom::sequence::tuple;
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use nom::{IResult, Offset, Slice};
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use nom_locate::LocatedSpan;
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use std::borrow::Cow;
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enum Token<'a> {
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PlainText(Cow<'a, str>),
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Sequence(Vec<Token<'a>>),
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Quote(Box<Token<'a>>),
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Small(Box<Token<'a>>),
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Big(Box<Token<'a>>),
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BoldItalic(Box<Token<'a>>),
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Bold(Box<Token<'a>>),
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Italic(Box<Token<'a>>),
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Center(Box<Token<'a>>),
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Strikethrough(Box<Token<'a>>),
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PlainTag(Cow<'a, str>),
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InlineCode(Cow<'a, str>),
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InlineMath(Cow<'a, str>),
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}
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impl Token<'_> {
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fn owned(&self) -> Token<'static> {
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match self {
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Token::PlainText(text) => Token::PlainText(Cow::Owned(text.clone().into_owned())),
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Token::Sequence(tokens) => Token::Sequence(tokens.iter().map(Token::owned).collect()),
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Token::Quote(inner) => Token::Quote(Box::new(inner.owned())),
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Token::Small(inner) => Token::Small(Box::new(inner.owned())),
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Token::Big(inner) => Token::Big(Box::new(inner.owned())),
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Token::BoldItalic(inner) => Token::BoldItalic(Box::new(inner.owned())),
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Token::Bold(inner) => Token::Bold(Box::new(inner.owned())),
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Token::Italic(inner) => Token::Italic(Box::new(inner.owned())),
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Token::Center(inner) => Token::Center(Box::new(inner.owned())),
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Token::Strikethrough(inner) => Token::Strikethrough(Box::new(inner.owned())),
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Token::PlainTag(tag) => Token::PlainTag(Cow::Owned(tag.clone().into_owned())),
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Token::InlineCode(code) => Token::InlineCode(Cow::Owned(code.clone().into_owned())),
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Token::InlineMath(math) => Token::InlineMath(Cow::Owned(math.clone().into_owned())),
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}
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}
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}
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type Span<'a> = LocatedSpan<&'a str>;
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trait SliceOffset {
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fn up_to(&self, other: &Self) -> Self;
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fn fragment_between<'a>(&self, other: &Self) -> &'a str
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where
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Self: 'a;
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}
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impl SliceOffset for Span<'_> {
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fn up_to(&self, other: &Self) -> Self {
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self.slice(..self.offset(other))
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}
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fn fragment_between<'a>(&self, other: &Self) -> &'a str
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where
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Self: 'a,
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{
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self.up_to(other).into_fragment()
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}
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}
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const fn boxing_sequence<'a>(
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func: impl Fn(Box<Token<'a>>) -> Token<'a>,
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) -> impl Fn(Vec<Token<'a>>) -> Token<'a> {
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move |tokens| func(Box::new(Token::Sequence(tokens)))
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}
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const fn collect_char_sequence<'a>(
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func: impl Fn(Cow<'a, str>) -> Token<'a>,
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) -> impl Fn(Vec<char>) -> Token<'a> {
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move |chars| func(Cow::Owned(chars.into_iter().collect()))
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}
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fn spliced<'a>(
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segments: &[Span<'a>],
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func: impl Fn(Span) -> IResult<Span, Token>,
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parent: Span<'a>,
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) -> IResult<Span<'a>, Token<'static>, nom::error::Error<Span<'a>>> {
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let combined = segments
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.iter()
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.copied()
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.map(Span::into_fragment)
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.collect::<String>();
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let cum_offset_combined = segments
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.iter()
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.scan(0, |acc, &x| {
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*acc += x.len();
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Some(*acc)
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})
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.collect::<Vec<_>>();
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let current_seg = |input: Span| {
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cum_offset_combined
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.iter()
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.enumerate()
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.filter(|(_, &o)| o >= input.location_offset())
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.map(|(i, o)| (segments[i], o))
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.last()
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};
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type NE<E> = nom::Err<E>;
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type NomError<'x> = nom::error::Error<Span<'x>>;
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let quote_span = Span::new(&combined);
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let (input, inner) = match func(quote_span) {
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Ok((input, token)) => (input, token.owned()),
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Err(e) => {
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return match e {
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NE::Error(e) => {
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let offset_new = e.input.location_offset();
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if let Some((seg_parent, offset_seg_new)) = current_seg(e.input) {
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let offset = offset_new - offset_seg_new;
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let offset_orig = offset + seg_parent.location_offset();
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Err(NE::Error(NomError::new(
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Span::new(&parent.into_fragment()[offset_orig..]),
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e.code,
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)))
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} else {
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// ???
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Err(NE::Failure(NomError::new(parent, ErrorKind::Fail)))
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}
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}
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NE::Failure(e) => Err(NE::Error(NomError::new(parent, e.code))),
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NE::Incomplete(i) => Err(NE::Incomplete(i)),
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};
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}
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};
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let out = if let Some((seg_parent, offset_seg_new)) = current_seg(input) {
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let offset = input.location_offset() - offset_seg_new;
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let offset_orig = offset + seg_parent.location_offset();
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parent.slice(offset_orig..)
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} else {
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parent
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};
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Ok((out, Token::Quote(Box::new(inner.owned()))))
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}
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fn space(input: Span) -> IResult<Span, Token> {
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let start = input;
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let (input, _) = alt((complete::char('\u{0020}'), complete::char('\u{3000}'), tab))(input)?;
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Ok((
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input,
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Token::PlainText(start.fragment_between(&input).into()),
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))
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}
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struct Context;
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impl Context {
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const fn partial<'a>(
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&self,
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func: impl Fn(&Self, Span<'a>) -> IResult<Span<'a>, Token<'a>> + 'static,
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) -> impl Fn(Span<'a>) -> IResult<Span<'a>, Token<'a>> + '_ {
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move |input| func(self, input)
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}
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fn root<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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let (input, token) = alt((self.partial(Self::tag_quote),))(input)?;
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Ok((input, token))
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}
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fn inline<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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let (input, token) = alt((self.partial(Self::tag_small), self.partial(Self::text)))(input)?;
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Ok((input, token))
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}
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fn tag_quote<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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let (input, leading_spaces) = tuple((opt(line_ending), opt(line_ending)))(input)?;
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if let (None, None) = leading_spaces {
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if input.get_column() != 0 {
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return fail(input);
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}
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}
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let quote_line = |input| tuple((tag(">"), opt(space), not_line_ending))(input);
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let orig_input = input;
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let (input, lines) = separated_list1(line_ending, quote_line)(input)?;
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let quote_lines = lines
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.into_iter()
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.map(|(_, _, text)| text)
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.collect::<Vec<_>>();
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if quote_lines.len() == 1
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&& quote_lines
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.iter()
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.map(Span::fragment)
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.copied()
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.any(&str::is_empty)
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{
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return fail(input);
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}
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let (_, inner) = spliced("e_lines, space, orig_input)?;
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let (input, _) = tuple((opt(line_ending), opt(line_ending)))(input)?;
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Ok((input, Token::Quote(Box::new(inner))))
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}
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const fn tag_delimited<'a, 'b: 'a, T>(
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&'a self,
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start: &'b str,
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end: &'b str,
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escape: bool,
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matcher_inner: impl Fn(Span<'b>) -> IResult<Span<'b>, T> + 'a,
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mapper: impl Fn(Vec<T>) -> Token<'b> + 'a,
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) -> impl Fn(Span<'b>) -> IResult<Span<'b>, Token<'b>> + '_ {
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move |input| {
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let opening_tag = &tag(start);
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let closing_tag = &tag(end);
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if escape {
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if let Ok((input_escaped, (_, mark))) = tuple((tag("\\"), opening_tag))(input) {
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return Ok((input_escaped, Token::PlainText(Cow::Borrowed(&mark))));
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}
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}
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let begin = input;
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let (post_open, _) = opening_tag(input)?;
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let res = tuple((
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many1(tuple((not(closing_tag), &matcher_inner))),
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closing_tag,
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))(post_open);
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if let Err(nom::Err::Error(nom::error::Error { .. })) = res {
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return Ok((
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post_open,
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Token::PlainText(begin.fragment_between(&post_open).into()),
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));
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}
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let (input, (inner, _)) = res?;
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let inner = inner.into_iter().map(|(_, t)| t).collect::<Vec<_>>();
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Ok((input, mapper(inner)))
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}
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}
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fn tag_small<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"<small>",
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"</small>",
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false,
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self.partial(Self::inline),
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boxing_sequence(Token::Small),
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)(input)
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}
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// TODO: CommonMark flanking rules
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fn tag_bold_italic_asterisk<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"***",
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"***",
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true,
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self.partial(Self::inline),
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boxing_sequence(Token::BoldItalic),
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)(input)
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}
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// TODO: CommonMark flanking rules
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fn tag_bold_italic_underscore<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"___",
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"___",
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true,
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self.partial(Self::inline),
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boxing_sequence(Token::BoldItalic),
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)(input)
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}
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fn tag_bold<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"<b>",
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"</b>",
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false,
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self.partial(Self::inline),
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boxing_sequence(Token::Bold),
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)(input)
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}
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// TODO: CommonMark flanking rules
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fn tag_bold_asterisk<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"**",
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"**",
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true,
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self.partial(Self::inline),
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boxing_sequence(Token::Bold),
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)(input)
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}
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// TODO: CommonMark flanking rules
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fn tag_bold_underscore<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"__",
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"__",
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true,
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self.partial(Self::inline),
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boxing_sequence(Token::Bold),
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)(input)
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}
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fn tag_italic<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"<i>",
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"</i>",
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false,
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self.partial(Self::inline),
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boxing_sequence(Token::Italic),
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)(input)
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}
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// TODO: CommonMark flanking rules
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fn tag_italic_asterisk<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"*",
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"*",
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true,
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self.partial(Self::inline),
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boxing_sequence(Token::Italic),
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)(input)
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}
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// TODO: CommonMark flanking rules
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fn tag_italic_underscore<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"_",
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"_",
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true,
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self.partial(Self::inline),
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boxing_sequence(Token::Italic),
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)(input)
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}
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fn tag_strikethrough<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"<s>",
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"</s>",
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false,
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self.partial(Self::inline),
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boxing_sequence(Token::Strikethrough),
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)(input)
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}
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// TODO: CommonMark flanking rules
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fn tag_strikethrough_tilde<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"~~",
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"~~",
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true,
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move |input| {
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tuple((not_line_ending, self.partial(Self::inline)))(input).map(|(i, t)| (i, t.1))
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},
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boxing_sequence(Token::Strikethrough),
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)(input)
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}
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fn tag_inline_code<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"`",
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"",
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true,
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move |input| {
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tuple((not(alt((tag("`"), tag("´"), line_ending))), anychar))(input)
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.map(|(i, (_skip, c))| (i, c))
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},
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collect_char_sequence(Token::InlineCode),
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)(input)
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}
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fn tag_inline_math<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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self.tag_delimited(
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"\\(",
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"\\)",
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false,
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move |input| tuple((not_line_ending, anychar))(input).map(|(i, (_skip, c))| (i, c)),
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collect_char_sequence(Token::InlineMath),
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)(input)
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}
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fn text<'a>(&self, input: Span<'a>) -> IResult<Span<'a>, Token<'a>> {
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let before = input;
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let (input, _) = anychar(input)?;
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Ok((
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input,
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Token::PlainText(before.fragment_between(&input).into()),
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))
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}
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}
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