inline: always push events from parse methods

in order to more conveniently allow pushing in arbitrary order

parse methods now return an Option<()> that functions kind of like a
std::ops::ControlFlow. Some(()) means the token was parsed, None means
continue parsing.
This commit is contained in:
Noah Hellman 2023-02-15 16:49:39 +01:00
parent 9429f90307
commit 491c5f2866

View file

@ -117,7 +117,16 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
self.span = self.span.empty_after();
}
fn parse_event(&mut self) -> Option<Event> {
fn push_sp(&mut self, kind: EventKind, span: Span) -> Option<()> {
self.events.push_back(Event { kind, span });
Some(())
}
fn push(&mut self, kind: EventKind) -> Option<()> {
self.push_sp(kind, self.span)
}
fn parse_event(&mut self) -> Option<()> {
self.reset_span();
self.eat().map(|first| {
self.parse_verbatim(&first)
@ -127,18 +136,17 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
.or_else(|| self.parse_footnote_reference(&first))
.or_else(|| self.parse_container(&first))
.or_else(|| self.parse_atom(&first))
.unwrap_or(Event {
kind: if matches!(first.kind, lex::Kind::Whitespace) {
.unwrap_or_else(|| {
self.push(if matches!(first.kind, lex::Kind::Whitespace) {
EventKind::Whitespace
} else {
EventKind::Str
},
span: self.span,
});
})
})
}
fn parse_verbatim(&mut self, first: &lex::Token) -> Option<Event> {
fn parse_verbatim(&mut self, first: &lex::Token) -> Option<()> {
match first.kind {
lex::Kind::Seq(lex::Sequence::Dollar) => {
let math_opt = (first.len <= 2)
@ -171,15 +179,9 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
}
.map(|(mut kind, opener_len)| {
let e_attr = self.events.len();
self.events.push_back(Event {
kind: EventKind::Placeholder,
span: Span::empty_at(self.span.start()),
});
self.push_sp(EventKind::Placeholder, Span::empty_at(self.span.start()));
let opener_event = self.events.len();
self.events.push_back(Event {
kind: EventKind::Enter(kind),
span: self.span,
});
self.push(EventKind::Enter(kind));
let mut span_inner = self.span.empty_after();
let mut span_outer = None;
@ -248,15 +250,8 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
span_inner = span_inner.with_end(pos);
}
self.events.push_back(Event {
kind: EventKind::Str,
span: span_inner,
});
let ev = Event {
kind: EventKind::Exit(kind),
span: span_outer.unwrap_or(self.span),
};
self.push_sp(EventKind::Str, span_inner);
self.push_sp(EventKind::Exit(kind), span_outer.unwrap_or(self.span));
if let Some((non_empty, span)) = self.ahead_attributes() {
self.span = span;
@ -267,12 +262,10 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
};
}
}
ev
})
}
fn parse_attributes(&mut self, first: &lex::Token) -> Option<Event> {
fn parse_attributes(&mut self, first: &lex::Token) -> Option<()> {
if first.kind == lex::Kind::Open(Delimiter::Brace) {
let mut ahead = self.lexer.chars();
let (mut attr_len, mut has_attr) = attr::valid(std::iter::once('{').chain(&mut ahead));
@ -293,7 +286,7 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
.back()
.map_or(false, |e| e.kind == EventKind::Str);
Some(if set_attr {
if set_attr {
let i = self
.events
.iter()
@ -304,38 +297,21 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
.union(self.events[self.events.len() - 1].span);
self.events.drain(i..);
self.events.push_back(Event {
kind: EventKind::Attributes,
span: self.span,
});
self.events.push_back(Event {
kind: EventKind::Enter(Container::Span),
span: span_str.empty_before(),
});
self.events.push_back(Event {
kind: EventKind::Str,
span: span_str,
});
self.push(EventKind::Attributes);
self.push_sp(EventKind::Enter(Container::Span), span_str.empty_before());
self.push_sp(EventKind::Str, span_str);
Event {
kind: EventKind::Exit(Container::Span),
span: span_str.empty_after(),
}
return self.push_sp(EventKind::Exit(Container::Span), span_str.empty_after());
} else {
Event {
kind: EventKind::Placeholder,
span: self.span.empty_before(),
}
})
} else {
None
return self.push_sp(EventKind::Placeholder, self.span.empty_before());
}
}
} else {
None
}
None
}
fn parse_autolink(&mut self, first: &lex::Token) -> Option<Event> {
fn parse_autolink(&mut self, first: &lex::Token) -> Option<()> {
if first.kind == lex::Kind::Sym(Symbol::Lt) {
let mut ahead = self.lexer.chars();
let mut end = false;
@ -355,29 +331,19 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
})
.map(char::len_utf8)
.sum();
(end && is_url).then(|| {
if end && is_url {
self.lexer = lex::Lexer::new(ahead);
self.span = self.span.after(len);
self.events.push_back(Event {
kind: EventKind::Enter(Autolink),
span: self.span,
});
self.events.push_back(Event {
kind: EventKind::Str,
span: self.span,
});
self.push(EventKind::Enter(Autolink));
self.push(EventKind::Str);
self.span = self.span.after(1);
Event {
kind: EventKind::Exit(Autolink),
span: self.span,
}
})
} else {
None
return self.push(EventKind::Exit(Autolink));
}
}
None
}
fn parse_symbol(&mut self, first: &lex::Token) -> Option<Event> {
fn parse_symbol(&mut self, first: &lex::Token) -> Option<()> {
if first.kind == lex::Kind::Sym(Symbol::Colon) {
let mut ahead = self.lexer.chars();
let mut end = false;
@ -393,22 +359,18 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
})
.map(char::len_utf8)
.sum();
(end && valid).then(|| {
if end && valid {
self.lexer = lex::Lexer::new(ahead);
self.span = self.span.after(len);
let span = self.span;
self.span = self.span.after(1);
Event {
kind: EventKind::Atom(Symbol),
span,
}
})
} else {
None
return self.push_sp(EventKind::Atom(Symbol), span);
}
}
None
}
fn parse_footnote_reference(&mut self, first: &lex::Token) -> Option<Event> {
fn parse_footnote_reference(&mut self, first: &lex::Token) -> Option<()> {
if first.kind == lex::Kind::Open(Delimiter::Bracket)
&& matches!(
self.peek(),
@ -440,22 +402,18 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
})
.map(char::len_utf8)
.sum();
end.then(|| {
if end {
self.lexer = lex::Lexer::new(ahead);
self.span = self.span.after(len);
let ev = Event {
kind: EventKind::Atom(FootnoteReference),
span: self.span,
};
self.push(EventKind::Atom(FootnoteReference));
self.span = self.span.after(1);
ev
})
} else {
None
return Some(());
}
}
None
}
fn parse_container(&mut self, first: &lex::Token) -> Option<Event> {
fn parse_container(&mut self, first: &lex::Token) -> Option<()> {
Delim::from_token(first.kind).and_then(|(delim, dir)| {
self.openers
.iter()
@ -482,27 +440,22 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
}
let inner_span = self.events[e_opener].span.between(self.span);
let mut event_closer = match DelimEventKind::from(d) {
let mut closed = match DelimEventKind::from(d) {
DelimEventKind::Container(cont) => {
self.events[e_opener].kind = EventKind::Enter(cont);
Some(Event {
kind: EventKind::Exit(cont),
span: self.span,
})
self.push(EventKind::Exit(cont))
}
DelimEventKind::Quote(ty) => {
self.events[e_opener].kind =
EventKind::Atom(Atom::Quote { ty, left: true });
Some(Event {
kind: EventKind::Atom(Atom::Quote { ty, left: false }),
span: self.span,
})
self.push(EventKind::Atom(Atom::Quote { ty, left: false }))
}
DelimEventKind::Span(ty) => self.post_span(ty, e_opener),
};
self.openers.drain(o..);
if let Some(event_closer) = &mut event_closer {
if closed.is_some() {
let event_closer = &mut self.events.back_mut().unwrap();
if event_closer.span.is_empty()
&& matches!(
event_closer.kind,
@ -511,7 +464,6 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
)
)
{
debug_assert_eq!(self.events[e_opener].span, event_closer.span);
event_closer.span = inner_span;
self.events[e_opener].span = inner_span;
}
@ -525,18 +477,15 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
};
}
if event_closer.is_none() {
if closed.is_none() {
self.events[e_opener].kind = EventKind::Enter(Container::Span);
event_closer = Some(Event {
kind: EventKind::Exit(Container::Span),
span: self.span,
});
closed = self.push(EventKind::Exit(Container::Span));
}
self.span = span;
}
event_closer
closed
})
.or_else(|| {
if matches!(dir, Dir::Close) {
@ -559,24 +508,18 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
}
self.openers.push((delim, self.events.len()));
// push dummy event in case attributes are encountered after closing delimiter
self.events.push_back(Event {
kind: EventKind::Placeholder,
span: Span::empty_at(self.span.start()),
});
self.push_sp(EventKind::Placeholder, Span::empty_at(self.span.start()));
// use non-opener for now, replace if closed later
Some(Event {
kind: match delim {
Delim::SingleQuoted => EventKind::Atom(Quote {
ty: QuoteType::Single,
left: false,
}),
Delim::DoubleQuoted => EventKind::Atom(Quote {
ty: QuoteType::Double,
left: true,
}),
_ => EventKind::Str,
},
span: self.span,
self.push(match delim {
Delim::SingleQuoted => EventKind::Atom(Quote {
ty: QuoteType::Single,
left: false,
}),
Delim::DoubleQuoted => EventKind::Atom(Quote {
ty: QuoteType::Double,
left: true,
}),
_ => EventKind::Str,
})
})
})
@ -601,7 +544,7 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
}
}
fn post_span(&mut self, ty: SpanType, opener_event: usize) -> Option<Event> {
fn post_span(&mut self, ty: SpanType, opener_event: usize) -> Option<()> {
let mut ahead = self.lexer.chars();
match ahead.next() {
Some(opener @ ('[' | '(')) => {
@ -636,14 +579,11 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
self.events[opener_event].kind = EventKind::Enter(kind);
self.events[opener_event].span = span;
self.span = span.translate(1);
Event {
kind: EventKind::Exit(kind),
span,
}
self.push_sp(EventKind::Exit(kind), span);
})
}
fn parse_atom(&mut self, first: &lex::Token) -> Option<Event> {
fn parse_atom(&mut self, first: &lex::Token) -> Option<()> {
let atom =
match first.kind {
lex::Kind::Newline => Softbreak,
@ -652,19 +592,13 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
lex::Kind::Nbsp => Nbsp,
lex::Kind::Seq(lex::Sequence::Period) if first.len >= 3 => {
while self.span.len() > 3 {
self.events.push_back(Event {
kind: EventKind::Atom(Ellipsis),
span: self.span.with_len(3),
});
self.push_sp(EventKind::Atom(Ellipsis), self.span.with_len(3));
self.span = self.span.skip(3);
}
if self.span.len() == 3 {
Ellipsis
} else {
return Some(Event {
kind: EventKind::Str,
span: self.span,
});
return self.push(EventKind::Str);
}
}
lex::Kind::Seq(lex::Sequence::Hyphen) if first.len >= 2 => {
@ -681,13 +615,10 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
.chain(std::iter::repeat(EnDash).take(n))
.for_each(|atom| {
let l = if matches!(atom, EnDash) { 2 } else { 3 };
self.events.push_back(Event {
kind: EventKind::Atom(atom),
span: self.span.with_len(l),
});
self.push_sp(EventKind::Atom(atom), self.span.with_len(l));
self.span = self.span.skip(l);
});
return self.events.pop_back();
return Some(());
}
lex::Kind::Open(lex::Delimiter::BraceQuote1) => Quote {
ty: QuoteType::Single,
@ -710,10 +641,7 @@ impl<I: Iterator<Item = char> + Clone> Parser<I> {
_ => return None,
};
Some(Event {
kind: EventKind::Atom(atom),
span: self.span,
})
self.push(EventKind::Atom(atom))
}
}
@ -826,9 +754,7 @@ impl<I: Iterator<Item = char> + Clone> Iterator for Parser<I> {
matches!(ev.kind, EventKind::Str | EventKind::Whitespace)
})
{
if let Some(ev) = self.parse_event() {
self.events.push_back(ev);
} else {
if self.parse_event().is_none() {
break;
}
}