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inline: add ControlFlow enum
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needed to indicate that more input is needed

this is needed only for multiline attributes that require backtracking
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@hellux
hellux committed Mar 20, 2023
1 parent 53a192b commit bb65a06
Showing 1 changed file with 44 additions and 30 deletions.
74 changes: 44 additions & 30 deletions src/inline.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@ use lex::Symbol;

use Atom::*;
use Container::*;
use ControlFlow::*;

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Atom {
Expand Down Expand Up @@ -220,6 +221,15 @@ pub struct Parser<'s> {
verbatim: Option<VerbatimState>,
}

pub enum ControlFlow {
/// At least one event has been emitted, continue parsing the line.
Continue,
/// More lines are needed to emit an event.
More,
/// Parsing of the line is completed.
Done,
}

impl<'s> Parser<'s> {
pub fn new(src: &'s str) -> Self {
Self {
Expand All @@ -242,18 +252,18 @@ impl<'s> Parser<'s> {
debug_assert!(self.verbatim.is_none());
}

fn push_sp(&mut self, kind: EventKind<'s>, span: Span) -> Option<()> {
fn push_sp(&mut self, kind: EventKind<'s>, span: Span) -> Option<ControlFlow> {
self.events.push_back(Event { kind, span });
Some(())
Some(Continue)
}

fn push(&mut self, kind: EventKind<'s>) -> Option<()> {
fn push(&mut self, kind: EventKind<'s>) -> Option<ControlFlow> {
self.push_sp(kind, self.input.span)
}

fn parse_event(&mut self) -> Option<()> {
fn parse_event(&mut self) -> ControlFlow {
self.input.reset_span();
self.input.eat().map(|first| {
if let Some(first) = self.input.eat() {
let ctrl = self
.parse_verbatim(&first)
.or_else(|| self.parse_attributes(&first))
Expand All @@ -262,19 +272,21 @@ impl<'s> Parser<'s> {
.or_else(|| self.parse_footnote_reference(&first))
.or_else(|| self.parse_container(&first))
.or_else(|| self.parse_atom(&first))
.unwrap_or_else(|| {
self.push(EventKind::Str);
});
.unwrap_or_else(|| self.push(EventKind::Str).unwrap());

if matches!(first.kind, lex::Kind::Newline) {
self.input.span_line = Span::new(self.input.span.end(), self.input.span_line.end());
}

ctrl
})
} else if self.input.last() {
Done
} else {
More
}
}

fn parse_verbatim(&mut self, first: &lex::Token) -> Option<()> {
fn parse_verbatim(&mut self, first: &lex::Token) -> Option<ControlFlow> {
if let Some(VerbatimState {
event_opener,
len_opener,
Expand Down Expand Up @@ -336,15 +348,15 @@ impl<'s> Parser<'s> {
)
})
{
return Some(()); // skip whitespace
return Some(Continue); // skip whitespace
}
} else {
*non_whitespace_encountered = true;
*non_whitespace_last = Some((first.kind, self.events.len() + 1));
}
self.push(EventKind::Str);
};
Some(())
Some(Continue)
} else {
let (ty, len_opener) = match first.kind {
lex::Kind::DollarBacktick(l) if first.len - l as usize == 1 => {
Expand All @@ -369,7 +381,7 @@ impl<'s> Parser<'s> {
}
}

fn parse_attributes(&mut self, first: &lex::Token) -> Option<()> {
fn parse_attributes(&mut self, first: &lex::Token) -> Option<ControlFlow> {
if first.kind == lex::Kind::Open(Delimiter::Brace) {
let mut ahead = self.input.lexer.ahead().chars();
let (mut attr_len, mut has_attr) = attr::valid(std::iter::once('{').chain(&mut ahead));
Expand All @@ -395,14 +407,14 @@ impl<'s> Parser<'s> {
} else {
self.push_sp(EventKind::Placeholder, self.input.span.empty_before());
}
return Some(());
return Some(Continue);
}
}

None
}

fn parse_autolink(&mut self, first: &lex::Token) -> Option<()> {
fn parse_autolink(&mut self, first: &lex::Token) -> Option<ControlFlow> {
if first.kind == lex::Kind::Sym(Symbol::Lt) {
let mut ahead = self.input.lexer.ahead().chars();
let mut end = false;
Expand Down Expand Up @@ -434,7 +446,7 @@ impl<'s> Parser<'s> {
None
}

fn parse_symbol(&mut self, first: &lex::Token) -> Option<()> {
fn parse_symbol(&mut self, first: &lex::Token) -> Option<ControlFlow> {
if first.kind == lex::Kind::Sym(Symbol::Colon) {
let mut ahead = self.input.lexer.ahead().chars();
let mut end = false;
Expand All @@ -455,13 +467,13 @@ impl<'s> Parser<'s> {
self.input.span = self.input.span.after(len);
self.push(EventKind::Atom(Symbol));
self.input.span = self.input.span.after(1);
return Some(());
return Some(Continue);
}
}
None
}

fn parse_footnote_reference(&mut self, first: &lex::Token) -> Option<()> {
fn parse_footnote_reference(&mut self, first: &lex::Token) -> Option<ControlFlow> {
if first.kind == lex::Kind::Open(Delimiter::Bracket)
&& matches!(
self.input.peek(),
Expand Down Expand Up @@ -498,13 +510,13 @@ impl<'s> Parser<'s> {
self.input.span = self.input.span.after(len);
self.push(EventKind::Atom(FootnoteReference));
self.input.span = self.input.span.after(1);
return Some(());
return Some(Continue);
}
}
None
}

fn parse_container(&mut self, first: &lex::Token) -> Option<()> {
fn parse_container(&mut self, first: &lex::Token) -> Option<ControlFlow> {
self.openers
.iter()
.rposition(|(o, _)| o.closed_by(first.kind))
Expand Down Expand Up @@ -631,7 +643,7 @@ impl<'s> Parser<'s> {
span: span_spec,
};
self.events.drain(e_opener..);
Some(())
Some(Continue)
}
};

Expand Down Expand Up @@ -702,7 +714,7 @@ impl<'s> Parser<'s> {
})
}

fn parse_atom(&mut self, first: &lex::Token) -> Option<()> {
fn parse_atom(&mut self, first: &lex::Token) -> Option<ControlFlow> {
let atom = match first.kind {
lex::Kind::Newline => Softbreak,
lex::Kind::Hardbreak => Hardbreak,
Expand Down Expand Up @@ -736,7 +748,7 @@ impl<'s> Parser<'s> {
self.push_sp(EventKind::Atom(atom), self.input.span.with_len(l));
self.input.span = self.input.span.skip(l);
});
return Some(());
return Some(Continue);
}
lex::Kind::Open(Delimiter::BraceQuote1) => Quote {
ty: QuoteType::Single,
Expand Down Expand Up @@ -970,13 +982,15 @@ impl<'s> Iterator for Parser<'s> {
.back()
.map_or(false, |ev| matches!(ev.kind, EventKind::Str))
{
if self.parse_event().is_none() {
if self.input.last() {
break;
} else if let Some(l) = self.input.ahead.pop_front() {
self.input.set_current_line(l);
} else {
return None;
match self.parse_event() {
Continue => {}
Done => break,
More => {
if let Some(l) = self.input.ahead.pop_front() {
self.input.set_current_line(l);
} else {
return None;
}
}
}
}
Expand Down

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