388 lines
11 KiB
Rust
388 lines
11 KiB
Rust
use crate::lex;
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use crate::Span;
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use lex::Delimiter;
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use lex::Symbol;
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use Atom::*;
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use Container::*;
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use NodeKind::*;
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub enum Atom {
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Softbreak,
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Hardbreak,
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Escape,
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Nbsp,
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OpenMarker, // ??
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Ellipses,
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ImageMarker, // ??
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EmDash,
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EnDash,
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Lt,
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Gt,
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Ampersand,
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Quote,
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}
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub struct Node {
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pub kind: NodeKind,
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pub span: Span,
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}
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub enum NodeKind {
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Str,
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// link
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Url,
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ImageSource,
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LinkReference,
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FootnoteReference,
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// verbatim
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Verbatim,
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RawFormat,
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InlineMath,
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DisplayMath,
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}
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#[derive(Debug, Copy, Clone, PartialEq, Eq)]
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pub enum Container {
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Span,
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Attributes,
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// typesetting
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Subscript,
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Superscript,
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Insert,
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Delete,
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Emphasis,
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Strong,
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//Mark,
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// smart quoting
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SingleQuoted,
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DoubleQuoted,
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}
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#[derive(Debug, PartialEq, Eq)]
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pub enum Event {
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Enter(Container),
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Exit(Container),
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Atom(Atom),
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Node(Node),
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}
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#[derive(Debug, Clone, Copy)]
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pub enum Dir {
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Open,
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Close,
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Both,
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}
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pub struct Parser<'s> {
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openers: Vec<Container>,
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close_containers: Option<usize>,
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next: Option<Event>,
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span: Span,
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lexer: std::iter::Peekable<lex::Lexer<'s>>,
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}
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impl<'s> Parser<'s> {
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pub fn new() -> Self {
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Self {
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openers: Vec::new(),
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close_containers: None,
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next: None,
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span: Span::new(0, 0),
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lexer: lex::Lexer::new("").peekable(),
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}
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}
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pub fn parse(&mut self, src: &'s str) {
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self.lexer = lex::Lexer::new(src).peekable();
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}
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fn eat(&mut self) -> Option<lex::Token> {
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let tok = self.lexer.next();
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if let Some(t) = &tok {
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self.span = self.span.extend(t.len);
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}
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tok
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}
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fn peek(&mut self) -> Option<&lex::Token> {
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self.lexer.peek()
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}
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fn reset_span(&mut self) {
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self.span = Span::empty_at(self.span.end());
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}
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fn node(&self, kind: NodeKind) -> Event {
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Event::Node(Node {
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span: self.span,
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kind,
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})
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}
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fn parse_event(&mut self) -> Option<Event> {
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self.reset_span();
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self.eat().map(|first| {
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self.parse_verbatim(&first)
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.or_else(|| self.parse_container(&first))
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.or_else(|| self.parse_atom(&first))
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.unwrap_or_else(|| self.node(Str))
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})
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}
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fn parse_atom(&mut self, first: &lex::Token) -> Option<Event> {
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match first.kind {
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lex::Kind::Escape => Some(Event::Atom(Escape)),
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lex::Kind::Nbsp => Some(Event::Atom(Nbsp)),
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lex::Kind::Sym(lex::Symbol::Lt) => Some(Event::Atom(Lt)),
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lex::Kind::Sym(lex::Symbol::Gt) => Some(Event::Atom(Gt)),
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lex::Kind::Sym(lex::Symbol::Quote2) => Some(Event::Atom(Quote)),
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_ => None,
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}
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}
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fn parse_verbatim(&mut self, first: &lex::Token) -> Option<Event> {
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match first.kind {
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lex::Kind::Seq(lex::Sequence::Dollar) => {
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let math_opt = (first.len <= 2)
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.then(|| {
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if let Some(lex::Token {
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kind: lex::Kind::Seq(lex::Sequence::Backtick),
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len,
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}) = self.peek()
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{
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Some((
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if first.len == 2 {
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DisplayMath
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} else {
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InlineMath
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},
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*len,
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))
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} else {
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None
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}
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})
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.flatten();
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if math_opt.is_some() {
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self.eat(); // backticks
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}
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math_opt
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}
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lex::Kind::Seq(lex::Sequence::Backtick) => Some((Verbatim, first.len)),
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_ => None,
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}
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.map(|(kind, opener_len)| {
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let mut span = Span::empty_at(self.span.end());
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while let Some(tok) = self.eat() {
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if matches!(tok.kind, lex::Kind::Seq(lex::Sequence::Backtick))
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&& tok.len == opener_len
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{
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break;
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}
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span = span.extend(tok.len);
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}
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Event::Node(Node { kind, span })
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})
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}
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fn parse_container(&mut self, first: &lex::Token) -> Option<Event> {
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match first.kind {
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lex::Kind::Sym(Symbol::Asterisk) => Some((Strong, Dir::Both)),
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lex::Kind::Sym(Symbol::Underscore) => Some((Emphasis, Dir::Both)),
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lex::Kind::Sym(Symbol::Caret) => Some((Superscript, Dir::Both)),
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lex::Kind::Sym(Symbol::Tilde) => Some((Subscript, Dir::Both)),
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lex::Kind::Sym(Symbol::Quote1) => Some((SingleQuoted, Dir::Both)),
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lex::Kind::Sym(Symbol::Quote2) => Some((DoubleQuoted, Dir::Both)),
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lex::Kind::Open(Delimiter::Bracket) => Some((Span, Dir::Open)),
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lex::Kind::Close(Delimiter::Bracket) => Some((Span, Dir::Close)),
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lex::Kind::Open(Delimiter::BraceAsterisk) => Some((Strong, Dir::Open)),
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lex::Kind::Close(Delimiter::BraceAsterisk) => Some((Strong, Dir::Close)),
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lex::Kind::Open(Delimiter::BraceCaret) => Some((Superscript, Dir::Open)),
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lex::Kind::Close(Delimiter::BraceCaret) => Some((Superscript, Dir::Close)),
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//lex::Kind::Open(Delimiter::BraceEqual) => Some((Mark, Dir::Open)),
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//lex::Kind::Close(Delimiter::BraceEqual) => Some((Mark, Dir::Close)),
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lex::Kind::Open(Delimiter::BraceHyphen) => Some((Delete, Dir::Open)),
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lex::Kind::Close(Delimiter::BraceHyphen) => Some((Delete, Dir::Close)),
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lex::Kind::Open(Delimiter::BracePlus) => Some((Insert, Dir::Open)),
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lex::Kind::Close(Delimiter::BracePlus) => Some((Insert, Dir::Close)),
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lex::Kind::Open(Delimiter::BraceTilde) => Some((Subscript, Dir::Open)),
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lex::Kind::Close(Delimiter::BraceTilde) => Some((Subscript, Dir::Close)),
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lex::Kind::Open(Delimiter::BraceUnderscore) => Some((Emphasis, Dir::Open)),
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lex::Kind::Close(Delimiter::BraceUnderscore) => Some((Emphasis, Dir::Close)),
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_ => None,
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}
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.and_then(|(cont, dir)| {
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if matches!(dir, Dir::Close | Dir::Both) && self.openers.contains(&cont) {
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self.close_containers = self.openers.iter().rposition(|o| *o == cont);
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Some(Event::Exit(self.openers.pop().unwrap()))
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} else if matches!(dir, Dir::Open | Dir::Both) {
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self.openers.push(cont);
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Some(Event::Enter(cont))
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} else {
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None
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}
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})
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}
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}
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impl<'s> Iterator for Parser<'s> {
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type Item = Event;
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fn next(&mut self) -> Option<Self::Item> {
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self.next.take().or_else(|| {
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self.close_containers
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.and_then(|i| {
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if i < self.openers.len() {
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Some(Event::Exit(self.openers.pop().unwrap()))
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} else {
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self.close_containers = None;
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None
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}
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})
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.or_else(|| {
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let mut current = self.parse_event();
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if let Some(Event::Node(Node { kind: Str, span })) = &mut current {
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self.next = self.parse_event();
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while let Some(Event::Node(Node { kind: Str, span: s })) = self.next {
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*span = span.union(s);
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self.next = self.parse_event();
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}
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}
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current
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})
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.or_else(|| self.openers.pop().map(Event::Exit))
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})
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}
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}
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#[cfg(test)]
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mod test {
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use crate::Span;
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use super::Atom::*;
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use super::Container::*;
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use super::Event::*;
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use super::NodeKind::*;
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macro_rules! test_parse {
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($($st:ident,)? $src:expr $(,$($token:expr),* $(,)?)?) => {
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#[allow(unused)]
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let mut p = super::Parser::new();
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p.parse($src);
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let actual = p.collect::<Vec<_>>();
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let expected = &[$($($token),*,)?];
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assert_eq!(actual, expected, "\n\n{}\n\n", $src);
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};
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}
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impl super::NodeKind {
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pub fn span(self, start: usize, end: usize) -> super::Node {
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super::Node {
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span: Span::new(start, end),
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kind: self,
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}
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}
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}
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#[test]
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fn str() {
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test_parse!("abc", Node(Str.span(0, 3)));
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test_parse!("abc def", Node(Str.span(0, 7)));
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}
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#[test]
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fn verbatim() {
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test_parse!("`abc`", Node(Verbatim.span(1, 4)));
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test_parse!("`abc", Node(Verbatim.span(1, 4)));
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test_parse!("``abc``", Node(Verbatim.span(2, 5)));
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test_parse!("abc `def`", Node(Str.span(0, 4)), Node(Verbatim.span(5, 8)));
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}
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#[test]
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fn math() {
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test_parse!("$`abc`", Node(InlineMath.span(2, 5)));
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test_parse!("$$```abc", Node(DisplayMath.span(5, 8)));
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}
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#[test]
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fn container_basic() {
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test_parse!(
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"_abc_",
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Enter(Emphasis),
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Node(Str.span(1, 4)),
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Exit(Emphasis)
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);
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test_parse!(
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"{_abc_}",
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Enter(Emphasis),
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Node(Str.span(2, 5)),
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Exit(Emphasis)
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);
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}
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#[test]
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fn container_nest() {
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test_parse!(
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"{_{_abc_}_}",
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Enter(Emphasis),
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Enter(Emphasis),
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Node(Str.span(4, 7)),
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Exit(Emphasis),
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Exit(Emphasis)
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);
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test_parse!(
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"*_abc_*",
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Enter(Strong),
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Enter(Emphasis),
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Node(Str.span(2, 5)),
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Exit(Emphasis),
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Exit(Strong)
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);
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}
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#[test]
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fn container_unopened() {
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test_parse!("*}abc", Node(Str.span(0, 5)),);
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}
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#[test]
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fn container_close_parent() {
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test_parse!(
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"{*{_abc*}",
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Enter(Strong),
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Enter(Emphasis),
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Node(Str.span(4, 7)),
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Exit(Emphasis),
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Exit(Strong)
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);
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}
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#[test]
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fn container_close_block() {
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test_parse!(
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"{_abc",
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Enter(Emphasis),
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Node(Str.span(2, 5)),
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Exit(Emphasis)
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);
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test_parse!(
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"{_{*{_abc",
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Enter(Emphasis),
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Enter(Strong),
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Enter(Emphasis),
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Node(Str.span(6, 9)),
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Exit(Emphasis),
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Exit(Strong),
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Exit(Emphasis),
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);
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}
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}
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