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Refactor parser a bit

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This commit is contained in:
Laurenz 2021-05-21 23:58:34 +02:00
parent 6472c1e425
commit a175d37ff2
1 changed files with 27 additions and 32 deletions
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59
src/parse/parser.rs
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@ -51,7 +51,7 @@ pub enum Group {
Subheader,
/// A group ended by a semicolon or a line break: `;`, `\n`.
Stmt,
/// A group for a single expression. Not ended by something specific.
/// A group for a single expression, ended by a line break.
Expr,
}
@ -330,25 +330,23 @@ impl<'s> Parser<'s> {
scanner
}
/// Move to the next token, skipping whitespace and comments in code mode.
/// Move to the next token.
fn bump(&mut self) {
self.last_end = self.tokens.pos();
self.next_start = self.tokens.pos();
self.next = self.tokens.next();
match self.tokens.mode() {
TokenMode::Markup => {}
TokenMode::Code => loop {
match self.next {
Some(Token::Space(n)) if n < 1 || !self.in_line_group() => {}
Some(Token::LineComment(_)) => {}
Some(Token::BlockComment(_)) => {}
_ => break,
}
if self.tokens.mode() == TokenMode::Code {
// Skip whitespace and comments.
while match self.next {
Some(Token::Space(n)) => n < 1 || !self.stop_at_newline(),
Some(Token::LineComment(_)) => true,
Some(Token::BlockComment(_)) => true,
_ => false,
} {
self.next_start = self.tokens.pos();
self.next = self.tokens.next();
},
}
}
self.repeek();
@ -362,31 +360,28 @@ impl<'s> Parser<'s> {
None => return,
};
let inside = |x| self.kinds().any(|k| k == x);
match token {
Token::RightParen if inside(Group::Paren) => {}
Token::RightBracket if inside(Group::Bracket) => {}
Token::RightBrace if inside(Group::Brace) => {}
Token::Semicolon if inside(Group::Stmt) => {}
Token::Pipe if inside(Group::Subheader) => {}
Token::Space(n) if n >= 1 && self.in_line_group() => {}
_ => return,
if match token {
Token::RightParen => self.inside(Group::Paren),
Token::RightBracket => self.inside(Group::Bracket),
Token::RightBrace => self.inside(Group::Brace),
Token::Semicolon => self.inside(Group::Stmt),
Token::Pipe => self.inside(Group::Subheader),
Token::Space(n) => n >= 1 && self.stop_at_newline(),
_ => false,
} {
self.peeked = None;
}
self.peeked = None;
}
/// Whether the active group ends at a newline.
fn in_line_group(&self) -> bool {
matches!(
self.kinds().next_back(),
Some(Group::Stmt) | Some(Group::Expr)
)
fn stop_at_newline(&self) -> bool {
let active = self.groups.last().map(|group| group.kind);
matches!(active, Some(Group::Stmt) | Some(Group::Expr))
}
/// The outer groups.
fn kinds(&self) -> impl DoubleEndedIterator<Item = Group> + '_ {
self.groups.iter().map(|group| group.kind)
/// Whether we are inside the given group.
fn inside(&self, kind: Group) -> bool {
self.groups.iter().any(|g| g.kind == kind)
}
}