PR #39 add source map

Merge branch 'spans2'

.github/workflows/ci.yml

@@ -72,7 +72,6 @@ jobs:
       matrix:
         target:
           - parse
-          - parse_balance
           - html
     runs-on: ubuntu-latest
     steps:

examples/jotdown_wasm/demo.html

@@ -21,7 +21,10 @@
             output.innerText = jotdown_render(input.innerText);
         } else if (fmt.value == "events") {
             output.classList.add("verbatim")
-            output.innerText = jotdown_parse(input.innerText);
+            output.innerText = jotdown_parse(input.innerText, false);
+        } else if (fmt.value == "events_spans") {
+            output.classList.add("verbatim")
+            output.innerText = jotdown_parse(input.innerText, true);
         } else if (fmt.value == "events_indent") {
             output.classList.add("verbatim")
             output.innerText = jotdown_parse_indent(input.innerText);
@@ -50,6 +53,7 @@
         <option value="preview">preview</option>
         <option value="html">html</option>
         <option value="events">events</option>
+        <option value="events_spans">events (with offsets)</option>
         <option value="events_indent">events (indented)</option>
       </select>
     </div>

examples/jotdown_wasm/src/lib.rs

@@ -22,10 +22,16 @@ pub fn jotdown_render(djot: &str) -> String {
 
 #[must_use]
 #[wasm_bindgen]
-pub fn jotdown_parse(djot: &str) -> String {
+pub fn jotdown_parse(djot: &str, spans: bool) -> String {
-    jotdown::Parser::new(djot)
+    let mut out = String::new();
-        .map(|e| format!("{:?}\n", e))
+    for (e, sp) in jotdown::Parser::new(djot).into_offset_iter() {
-        .collect()
+        write!(out, "{:?}", e).unwrap();
+        if spans {
+            write!(out, " {:?} {:?}", &djot[sp.clone()], sp).unwrap();
+        }
+        writeln!(out).unwrap();
+    }
+    out
 }
 
 #[must_use]

src/inline.rs

@@ -12,9 +12,9 @@ use Container::*;
 use ControlFlow::*;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub enum Atom {
+pub enum Atom<'s> {
-    FootnoteReference,
+    FootnoteReference { label: &'s str },
-    Symbol,
+    Symbol(&'s str),
     Softbreak,
     Hardbreak,
     Escape,
@@ -26,7 +26,7 @@ pub enum Atom {
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum Container {
+pub enum Container<'s> {
     Span,
     Subscript,
     Superscript,
@@ -36,16 +36,14 @@ pub enum Container {
     Strong,
     Mark,
     Verbatim,
-    /// Span is the format.
+    RawFormat { format: &'s str },
-    RawFormat,
     InlineMath,
     DisplayMath,
     ReferenceLink(CowStrIndex),
     ReferenceImage(CowStrIndex),
     InlineLink(CowStrIndex),
     InlineImage(CowStrIndex),
-    /// Open delimiter span is URL, closing is '>'.
+    Autolink(&'s str),
-    Autolink,
 }
 
 type CowStrIndex = u32;
@@ -57,10 +55,10 @@ pub enum QuoteType {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub enum EventKind {
+pub enum EventKind<'s> {
-    Enter(Container),
+    Enter(Container<'s>),
-    Exit(Container),
+    Exit(Container<'s>),
-    Atom(Atom),
+    Atom(Atom<'s>),
     Str,
     Attributes {
         container: bool,
@@ -72,8 +70,8 @@ pub enum EventKind {
 type AttributesIndex = u32;
 
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub struct Event {
+pub struct Event<'s> {
-    pub kind: EventKind,
+    pub kind: EventKind<'s>,
     pub span: Span,
 }
 
@@ -218,7 +216,7 @@ pub struct Parser<'s> {
     openers: Vec<(Opener, usize)>,
     /// Buffer queue for next events. Events are buffered until no modifications due to future
     /// characters are needed.
-    events: std::collections::VecDeque<Event>,
+    events: std::collections::VecDeque<Event<'s>>,
     /// State if inside a verbatim container.
     verbatim: Option<VerbatimState>,
     /// State if currently parsing potential attributes.
@@ -268,12 +266,12 @@ impl<'s> Parser<'s> {
         self.store_attributes.clear();
     }
 
-    fn push_sp(&mut self, kind: EventKind, span: Span) -> Option<ControlFlow> {
+    fn push_sp(&mut self, kind: EventKind<'s>, span: Span) -> Option<ControlFlow> {
         self.events.push_back(Event { kind, span });
         Some(Continue)
     }
 
-    fn push(&mut self, kind: EventKind) -> Option<ControlFlow> {
+    fn push(&mut self, kind: EventKind<'s>) -> Option<ControlFlow> {
         self.push_sp(kind, self.input.span)
     }
 
@@ -310,17 +308,16 @@ impl<'s> Parser<'s> {
                 && matches!(first.kind, lex::Kind::Seq(Sequence::Backtick))
             {
                 let raw_format = self.input.ahead_raw_format();
-                let mut span_closer = self.input.span;
                 if let Some(span_format) = raw_format {
-                    self.events[event_opener].kind = EventKind::Enter(RawFormat);
+                    self.events[event_opener].kind = EventKind::Enter(RawFormat {
-                    self.events[event_opener].span = span_format;
+                        format: span_format.of(self.input.src),
-                    self.input.span = span_format.translate(1);
+                    });
-                    span_closer = span_format;
+                    self.input.span = Span::new(self.input.span.start(), span_format.end() + 1);
                 };
                 let ty_opener = if let EventKind::Enter(ty) = self.events[event_opener].kind {
                     debug_assert!(matches!(
                         ty,
-                        Verbatim | RawFormat | InlineMath | DisplayMath
+                        Verbatim | RawFormat { .. } | InlineMath | DisplayMath
                     ));
                     ty
                 } else {
@@ -330,7 +327,7 @@ impl<'s> Parser<'s> {
                 {
                     self.events.drain(*event_skip..);
                 }
-                self.push_sp(EventKind::Exit(ty_opener), span_closer);
+                self.push(EventKind::Exit(ty_opener));
                 self.verbatim = None;
                 if raw_format.is_none()
                     && self.input.peek().map_or(false, |t| {
@@ -527,7 +524,13 @@ impl<'s> Parser<'s> {
         self.input.span = Span::new(start_attr, state.end_attr);
         self.input.lexer = lex::Lexer::new(&self.input.src[state.end_attr..line_end]);
 
-        if !attrs.is_empty() {
+        if attrs.is_empty() {
+            if matches!(state.elem_ty, AttributesElementType::Container { .. }) {
+                let last = self.events.len() - 1;
+                self.events[last].span =
+                    Span::new(self.events[last].span.start(), self.input.span.end());
+            }
+        } else {
             let attr_index = self.store_attributes.len() as AttributesIndex;
             self.store_attributes.push(attrs);
             let attr_event = Event {
@@ -540,11 +543,13 @@ impl<'s> Parser<'s> {
             match state.elem_ty {
                 AttributesElementType::Container { e_placeholder } => {
                     self.events[e_placeholder] = attr_event;
+                    let last = self.events.len() - 1;
                     if matches!(self.events[e_placeholder + 1].kind, EventKind::Str) {
                         self.events[e_placeholder + 1].kind = EventKind::Enter(Span);
-                        let last = self.events.len() - 1;
                         self.events[last].kind = EventKind::Exit(Span);
                     }
+                    self.events[last].span =
+                        Span::new(self.events[last].span.start(), self.input.span.end());
                 }
                 AttributesElementType::Word => {
                     self.events.push_back(attr_event);
@@ -577,12 +582,13 @@ impl<'s> Parser<'s> {
                 .sum();
             if end && is_url {
                 self.input.lexer = lex::Lexer::new(ahead.as_str());
-                self.input.span = self.input.span.after(len);
+                let span_url = self.input.span.after(len);
-                self.push(EventKind::Enter(Autolink));
+                let url = span_url.of(self.input.src);
+                self.push(EventKind::Enter(Autolink(url)));
+                self.input.span = span_url;
                 self.push(EventKind::Str);
-                self.push(EventKind::Exit(Autolink));
                 self.input.span = self.input.span.after(1);
-                return Some(Continue);
+                return self.push(EventKind::Exit(Autolink(url)));
             }
         }
         None
@@ -606,10 +612,11 @@ impl<'s> Parser<'s> {
                 .sum();
             if end && valid {
                 self.input.lexer = lex::Lexer::new(ahead.as_str());
-                self.input.span = self.input.span.after(len);
+                let span_symbol = self.input.span.after(len);
-                self.push(EventKind::Atom(Symbol));
+                self.input.span = Span::new(self.input.span.start(), span_symbol.end() + 1);
-                self.input.span = self.input.span.after(1);
+                return self.push(EventKind::Atom(Atom::Symbol(
-                return Some(Continue);
+                    span_symbol.of(self.input.src),
+                )));
             }
         }
         None
@@ -649,10 +656,10 @@ impl<'s> Parser<'s> {
                 .sum();
             if end {
                 self.input.lexer = lex::Lexer::new(ahead.as_str());
-                self.input.span = self.input.span.after(len);
+                let span_label = self.input.span.after(len);
-                self.push(EventKind::Atom(FootnoteReference));
+                let label = span_label.of(self.input.src);
-                self.input.span = self.input.span.after(1);
+                self.input.span = Span::new(self.input.span.start(), span_label.end() + 1);
-                return Some(Continue);
+                return self.push(EventKind::Atom(FootnoteReference { label }));
             }
         }
         None
@@ -925,7 +932,7 @@ impl<'s> Parser<'s> {
         self.push(EventKind::Atom(atom))
     }
 
-    fn merge_str_events(&mut self, span_str: Span) -> Event {
+    fn merge_str_events(&mut self, span_str: Span) -> Event<'s> {
         let mut span = span_str;
         let should_merge = |e: &Event, span: Span| {
             matches!(e.kind, EventKind::Str | EventKind::Placeholder)
@@ -952,7 +959,7 @@ impl<'s> Parser<'s> {
         }
     }
 
-    fn apply_word_attributes(&mut self, span_str: Span) -> Event {
+    fn apply_word_attributes(&mut self, span_str: Span) -> Event<'s> {
         if let Some(i) = span_str
             .of(self.input.src)
             .bytes()
@@ -972,7 +979,7 @@ impl<'s> Parser<'s> {
             let attr = self.events.pop_front().unwrap();
             self.events.push_front(Event {
                 kind: EventKind::Exit(Span),
-                span: span_str.empty_after(),
+                span: attr.span,
             });
             self.events.push_front(Event {
                 kind: EventKind::Str,
@@ -1089,8 +1096,8 @@ impl Opener {
     }
 }
 
-enum DelimEventKind {
+enum DelimEventKind<'s> {
-    Container(Container),
+    Container(Container<'s>),
     Span(SpanType),
     Quote(QuoteType),
     Link {
@@ -1100,7 +1107,7 @@ enum DelimEventKind {
     },
 }
 
-impl From<Opener> for DelimEventKind {
+impl<'s> From<Opener> for DelimEventKind<'s> {
     fn from(d: Opener) -> Self {
         match d {
             Opener::Span(ty) => Self::Span(ty),
@@ -1127,7 +1134,7 @@ impl From<Opener> for DelimEventKind {
 }
 
 impl<'s> Iterator for Parser<'s> {
-    type Item = Event;
+    type Item = Event<'s>;
 
     fn next(&mut self) -> Option<Self::Item> {
         while self.events.is_empty()
@@ -1158,7 +1165,7 @@ impl<'s> Iterator for Parser<'s> {
             let ty_opener = if let EventKind::Enter(ty) = self.events[event_opener].kind {
                 debug_assert!(matches!(
                     ty,
-                    Verbatim | RawFormat | InlineMath | DisplayMath
+                    Verbatim | RawFormat { .. } | InlineMath | DisplayMath
                 ));
                 ty
             } else {
@@ -1266,7 +1273,7 @@ mod test {
             ),
             (Enter(Verbatim), "`"),
             (Str, "raw"),
-            (Exit(Verbatim), "`"),
+            (Exit(Verbatim), "`{#id}"),
             (Str, " post"),
         );
     }
@@ -1336,16 +1343,16 @@ mod test {
     fn raw_format() {
         test_parse!(
             "`raw`{=format}",
-            (Enter(RawFormat), "format"),
+            (Enter(RawFormat { format: "format" }), "`"),
             (Str, "raw"),
-            (Exit(RawFormat), "format"),
+            (Exit(RawFormat { format: "format" }), "`{=format}"),
         );
         test_parse!(
             "before `raw`{=format} after",
             (Str, "before "),
-            (Enter(RawFormat), "format"),
+            (Enter(RawFormat { format: "format" }), "`"),
             (Str, "raw"),
-            (Exit(RawFormat), "format"),
+            (Exit(RawFormat { format: "format" }), "`{=format}"),
             (Str, " after"),
         );
     }
@@ -1456,7 +1463,7 @@ mod test {
             ),
             (Enter(Span), ""),
             (Str, "[text]("),
-            (Exit(Span), ""),
+            (Exit(Span), "{.cls}"),
         );
     }
 
@@ -1520,7 +1527,7 @@ mod test {
                 "{.cls}",
             ),
             (Enter(Span), "["),
-            (Exit(Span), "]")
+            (Exit(Span), "]{.cls}")
         );
     }
 
@@ -1537,7 +1544,7 @@ mod test {
             ),
             (Enter(Span), "["),
             (Str, "abc"),
-            (Exit(Span), "]"),
+            (Exit(Span), "]{.def}"),
         );
         test_parse!("not a [span] {#id}.", (Str, "not a [span] "), (Str, "."));
     }
@@ -1555,7 +1562,7 @@ mod test {
             ),
             (Enter(Span), "["),
             (Str, "x_y"),
-            (Exit(Span), "]"),
+            (Exit(Span), "]{.bar_}"),
         );
     }
 
@@ -1563,24 +1570,24 @@ mod test {
     fn autolink() {
         test_parse!(
             "<https://example.com>",
-            (Enter(Autolink), "https://example.com"),
+            (Enter(Autolink("https://example.com",)), "<"),
             (Str, "https://example.com"),
-            (Exit(Autolink), "https://example.com")
+            (Exit(Autolink("https://example.com",)), ">")
         );
         test_parse!(
             "<a@b.c>",
-            (Enter(Autolink), "a@b.c"),
+            (Enter(Autolink("a@b.c")), "<"),
             (Str, "a@b.c"),
-            (Exit(Autolink), "a@b.c"),
+            (Exit(Autolink("a@b.c")), ">"),
         );
         test_parse!(
             "<http://a.b><http://c.d>",
-            (Enter(Autolink), "http://a.b"),
+            (Enter(Autolink("http://a.b")), "<"),
             (Str, "http://a.b"),
-            (Exit(Autolink), "http://a.b"),
+            (Exit(Autolink("http://a.b")), ">"),
-            (Enter(Autolink), "http://c.d"),
+            (Enter(Autolink("http://c.d")), "<"),
             (Str, "http://c.d"),
-            (Exit(Autolink), "http://c.d"),
+            (Exit(Autolink("http://c.d")), ">"),
         );
         test_parse!("<not-a-url>", (Str, "<not-a-url>"));
     }
@@ -1590,7 +1597,7 @@ mod test {
         test_parse!(
             "text[^footnote]. more text",
             (Str, "text"),
-            (Atom(FootnoteReference), "footnote"),
+            (Atom(FootnoteReference { label: "footnote" }), "[^footnote]"),
             (Str, ". more text"),
         );
     }
@@ -1687,7 +1694,7 @@ mod test {
             ),
             (Enter(Emphasis), "_"),
             (Str, "abc def"),
-            (Exit(Emphasis), "_"),
+            (Exit(Emphasis), "_{.attr}"),
         );
     }
 
@@ -1697,13 +1704,13 @@ mod test {
             "_abc def_{}",
             (Enter(Emphasis), "_"),
             (Str, "abc def"),
-            (Exit(Emphasis), "_"),
+            (Exit(Emphasis), "_{}"),
         );
         test_parse!(
             "_abc def_{ % comment % } ghi",
             (Enter(Emphasis), "_"),
             (Str, "abc def"),
-            (Exit(Emphasis), "_"),
+            (Exit(Emphasis), "_{ % comment % }"),
             (Str, " ghi"),
         );
     }
@@ -1721,7 +1728,7 @@ mod test {
             ),
             (Enter(Emphasis), "_"),
             (Str, "abc def"),
-            (Exit(Emphasis), "_"),
+            (Exit(Emphasis), "_{.a}{.b}{.c}"),
             (Str, " "),
         );
     }
@@ -1739,7 +1746,7 @@ mod test {
             ),
             (Enter(Span), ""),
             (Str, "word"),
-            (Exit(Span), ""),
+            (Exit(Span), "{a=b}"),
         );
         test_parse!(
             "some word{.a}{.b} with attrs",
@@ -1753,7 +1760,7 @@ mod test {
             ),
             (Enter(Span), ""),
             (Str, "word"),
-            (Exit(Span), ""),
+            (Exit(Span), "{.a}{.b}"),
             (Str, " with attrs"),
         );
     }

src/lib.rs

@@ -51,6 +51,7 @@
 use std::fmt;
 use std::fmt::Write as FmtWrite;
 use std::io;
+use std::ops::Range;
 
 #[cfg(feature = "html")]
 pub mod html;
@@ -60,7 +61,6 @@ mod block;
 mod inline;
 mod lex;
 mod span;
-mod tree;
 
 use span::Span;
 
@@ -555,13 +555,14 @@ pub struct Parser<'s> {
     src: &'s str,
 
     /// Block tree parsed at first.
-    tree: block::Tree,
+    blocks: std::iter::Peekable<std::vec::IntoIter<block::Event<'s>>>,
 
     /// Contents obtained by the prepass.
     pre_pass: PrePass<'s>,
 
-    /// Last parsed block attributes
+    /// Last parsed block attributes, and its starting offset.
     block_attributes: Attributes<'s>,
+    block_attributes_pos: Option<usize>,
 
     /// Current table row is a head row.
     table_head_row: bool,
@@ -576,7 +577,7 @@ pub struct Parser<'s> {
 #[derive(Clone)]
 struct Heading {
     /// Location of heading in src.
-    location: usize,
+    location: u32,
     /// Automatically generated id from heading text.
     id_auto: String,
     /// Text of heading, formatting stripped.
@@ -598,28 +599,50 @@ struct PrePass<'s> {
 
 impl<'s> PrePass<'s> {
     #[must_use]
-    fn new(src: &'s str, mut tree: block::Tree, inline_parser: &mut inline::Parser<'s>) -> Self {
+    fn new(
+        src: &'s str,
+        blocks: std::slice::Iter<block::Event<'s>>,
+        inline_parser: &mut inline::Parser<'s>,
+    ) -> Self {
         let mut link_definitions = Map::new();
         let mut headings: Vec<Heading> = Vec::new();
         let mut used_ids: Set<&str> = Set::new();
 
+        let mut blocks = blocks.peekable();
+
         let mut attr_prev: Option<Span> = None;
-        while let Some(e) = tree.next() {
+        while let Some(e) = blocks.next() {
             match e.kind {
-                tree::EventKind::Enter(block::Node::Leaf(block::Leaf::LinkDefinition)) => {
+                block::EventKind::Enter(block::Node::Leaf(block::Leaf::LinkDefinition {
+                    label,
+                })) => {
+                    fn next_is_inline(
+                        bs: &mut std::iter::Peekable<std::slice::Iter<block::Event>>,
+                    ) -> bool {
+                        matches!(bs.peek().map(|e| &e.kind), Some(block::EventKind::Inline))
+                    }
+
                     // All link definition tags have to be obtained initially, as references can
                     // appear before the definition.
-                    let tag = e.span.of(src);
                     let attrs =
                         attr_prev.map_or_else(Attributes::new, |sp| attr::parse(sp.of(src)));
-                    let url = match tree.count_children() {
+                    let url = if !next_is_inline(&mut blocks) {
-                        0 => "".into(),
+                        "".into()
-                        1 => tree.take_inlines().next().unwrap().of(src).trim().into(),
+                    } else {
-                        _ => tree.take_inlines().map(|sp| sp.of(src).trim()).collect(),
+                        let start = blocks.next().unwrap().span.of(src).trim();
-                    };
+                        if !next_is_inline(&mut blocks) {
-                    link_definitions.insert(tag, (url, attrs));
+                            start.into()
+                        } else {
+                            let mut url = start.to_string();
+                            while next_is_inline(&mut blocks) {
+                                url.push_str(blocks.next().unwrap().span.of(src).trim());
                             }
-                tree::EventKind::Enter(block::Node::Leaf(block::Leaf::Heading { .. })) => {
+                            url.into()
+                        }
+                    };
+                    link_definitions.insert(label, (url, attrs));
+                }
+                block::EventKind::Enter(block::Node::Leaf(block::Leaf::Heading { .. })) => {
                     // All headings ids have to be obtained initially, as references can appear
                     // before the heading. Additionally, determining the id requires inline parsing
                     // as formatting must be removed.
@@ -634,10 +657,21 @@ impl<'s> PrePass<'s> {
                     let mut id_auto = String::new();
                     let mut text = String::new();
                     let mut last_whitespace = true;
-                    let inlines = tree.take_inlines().collect::<Vec<_>>();
                     inline_parser.reset();
-                    inlines.iter().enumerate().for_each(|(i, sp)| {
+                    let mut last_end = 0;
-                        inline_parser.feed_line(*sp, i == inlines.len() - 1);
+                    loop {
+                        let span_inline = blocks.next().and_then(|e| {
+                            if matches!(e.kind, block::EventKind::Inline) {
+                                last_end = e.span.end();
+                                Some(e.span)
+                            } else {
+                                None
+                            }
+                        });
+                        inline_parser.feed_line(
+                            span_inline.unwrap_or_else(|| Span::empty_at(last_end)),
+                            span_inline.is_none(),
+                        );
                         inline_parser.for_each(|ev| match ev.kind {
                             inline::EventKind::Str => {
                                 text.push_str(ev.span.of(src));
@@ -662,8 +696,11 @@ impl<'s> PrePass<'s> {
                                 id_auto.push('-');
                             }
                             _ => {}
-                        })
                         });
+                        if span_inline.is_none() {
+                            break;
+                        }
+                    }
                     id_auto.drain(id_auto.trim_end_matches('-').len()..);
 
                     // ensure id unique
@@ -689,17 +726,17 @@ impl<'s> PrePass<'s> {
                         std::mem::transmute::<&str, &'static str>(id_auto.as_ref())
                     });
                     headings.push(Heading {
-                        location: e.span.start(),
+                        location: e.span.start() as u32,
                         id_auto,
                         text,
                         id_override,
                     });
                 }
-                tree::EventKind::Atom(block::Atom::Attributes) => {
+                block::EventKind::Atom(block::Atom::Attributes) => {
                     attr_prev = Some(e.span);
                 }
-                tree::EventKind::Enter(..)
+                block::EventKind::Enter(..)
-                | tree::EventKind::Exit(block::Node::Container(block::Container::Section {
+                | block::EventKind::Exit(block::Node::Container(block::Container::Section {
                     ..
                 })) => {}
                 _ => {
@@ -723,7 +760,7 @@ impl<'s> PrePass<'s> {
         h.id_override.as_ref().unwrap_or(&h.id_auto)
     }
 
-    fn heading_id_by_location(&self, location: usize) -> Option<&str> {
+    fn heading_id_by_location(&self, location: u32) -> Option<&str> {
         self.headings
             .binary_search_by_key(&location, |h| h.location)
             .ok()
@@ -741,22 +778,133 @@ impl<'s> PrePass<'s> {
 impl<'s> Parser<'s> {
     #[must_use]
     pub fn new(src: &'s str) -> Self {
-        let tree = block::parse(src);
+        let blocks = block::parse(src);
         let mut inline_parser = inline::Parser::new(src);
-        let pre_pass = PrePass::new(src, tree.clone(), &mut inline_parser);
+        let pre_pass = PrePass::new(src, blocks.iter(), &mut inline_parser);
 
         Self {
             src,
-            tree,
+            blocks: blocks.into_iter().peekable(),
             pre_pass,
             block_attributes: Attributes::new(),
+            block_attributes_pos: None,
             table_head_row: false,
             verbatim: false,
             inline_parser,
         }
     }
 
-    fn inline(&mut self) -> Option<Event<'s>> {
+    /// Turn the [`Parser`] into an iterator of tuples, each with an [`Event`] and a start/end byte
+    /// offset for its corresponding input (as a [`Range<usize>`]).
+    ///
+    /// Generally, the range of each event does not overlap with any other event and the ranges are
+    /// in same order as the events are emitted, i.e. the start offset of an event must be greater
+    /// or equal to the (exclusive) end offset of all events that were emitted before that event.
+    /// However, there are some exceptions to this rule:
+    ///
+    /// - Blank lines inbetween block attributes and the block causes the blankline events to
+    /// overlap with the block start event.
+    /// - Caption events are emitted before the table rows while the input for the caption content
+    /// is located after the table rows, causing the ranges to be out of order.
+    ///
+    /// Characters between events, that are not part of any event range, are typically whitespace
+    /// but may also consist of unattached attributes or `>` characters from blockquotes.
+    ///
+    /// # Examples
+    ///
+    /// Start and end events of containers correspond only to the start and end markers for that
+    /// container, not its inner content:
+    ///
+    /// ```
+    /// # use jotdown::*;
+    /// # use jotdown::Event::*;
+    /// # use jotdown::Container::*;
+    /// let input = "> _hello_ [text](url)\n";
+    /// assert!(matches!(
+    ///     Parser::new(input)
+    ///         .into_offset_iter()
+    ///         .map(|(e, r)| (&input[r], e))
+    ///         .collect::<Vec<_>>()
+    ///         .as_slice(),
+    ///     &[
+    ///         (">", Start(Blockquote, ..)),
+    ///         ("", Start(Paragraph, ..)),
+    ///         ("_", Start(Emphasis, ..)),
+    ///         ("hello", Str(..)),
+    ///         ("_", End(Emphasis)),
+    ///         (" ", Str(..)),
+    ///         ("[", Start(Link { .. }, ..)),
+    ///         ("text", Str(..)),
+    ///         ("](url)", End(Link { .. })),
+    ///         ("", End(Paragraph)),
+    ///         ("", End(Blockquote)),
+    ///     ],
+    /// ));
+    /// ```
+    ///
+    /// _Block_ attributes that belong to a container are included in the  _start_ event.  _Inline_
+    /// attributes that belong to a container are included in the _end_ event:
+    ///
+    /// ```
+    /// # use jotdown::*;
+    /// # use jotdown::Event::*;
+    /// # use jotdown::Container::*;
+    /// let input = "
+    /// {.quote}
+    /// > [Hello]{lang=en} world!";
+    /// assert!(matches!(
+    ///     Parser::new(input)
+    ///         .into_offset_iter()
+    ///         .map(|(e, r)| (&input[r], e))
+    ///         .collect::<Vec<_>>()
+    ///         .as_slice(),
+    ///     &[
+    ///         ("\n", Blankline),
+    ///         ("{.quote}\n>", Start(Blockquote, ..)),
+    ///         ("", Start(Paragraph, ..)),
+    ///         ("[", Start(Span, ..)),
+    ///         ("Hello", Str(..)),
+    ///         ("]{lang=en}", End(Span)),
+    ///         (" world!", Str(..)),
+    ///         ("", End(Paragraph)),
+    ///         ("", End(Blockquote)),
+    ///     ],
+    /// ));
+    /// ```
+    ///
+    /// Inline events that span multiple lines may contain characters from outer block containers
+    /// (e.g. `>` characters from blockquotes or whitespace from list items):
+    ///
+    /// ```
+    /// # use jotdown::*;
+    /// # use jotdown::Event::*;
+    /// # use jotdown::Container::*;
+    /// let input = "
+    /// > [txt](multi
+    /// > line)";
+    /// assert!(matches!(
+    ///     Parser::new(input)
+    ///         .into_offset_iter()
+    ///         .map(|(e, r)| (&input[r], e))
+    ///         .collect::<Vec<_>>()
+    ///         .as_slice(),
+    ///     &[
+    ///         ("\n", Blankline),
+    ///         (">", Start(Blockquote, ..)),
+    ///         ("", Start(Paragraph, ..)),
+    ///         ("[", Start(Link { .. }, ..)),
+    ///         ("txt", Str(..)),
+    ///         ("](multi\n> line)", End(Link { .. })),
+    ///         ("", End(Paragraph)),
+    ///         ("", End(Blockquote)),
+    ///     ],
+    /// ));
+    /// ```
+    pub fn into_offset_iter(self) -> OffsetIter<'s> {
+        OffsetIter { parser: self }
+    }
+
+    fn inline(&mut self) -> Option<(Event<'s>, Range<usize>)> {
         let next = self.inline_parser.next()?;
 
         let (inline, mut attributes) = match next {
@@ -772,16 +920,14 @@ impl<'s> Parser<'s> {
 
         inline.map(|inline| {
             let enter = matches!(inline.kind, inline::EventKind::Enter(_));
-            match inline.kind {
+            let event = match inline.kind {
                 inline::EventKind::Enter(c) | inline::EventKind::Exit(c) => {
                     let t = match c {
                         inline::Container::Span => Container::Span,
                         inline::Container::Verbatim => Container::Verbatim,
                         inline::Container::InlineMath => Container::Math { display: false },
                         inline::Container::DisplayMath => Container::Math { display: true },
-                        inline::Container::RawFormat => Container::RawInline {
+                        inline::Container::RawFormat { format } => Container::RawInline { format },
-                            format: inline.span.of(self.src),
-                        },
                         inline::Container::Subscript => Container::Subscript,
                         inline::Container::Superscript => Container::Superscript,
                         inline::Container::Insert => Container::Insert,
@@ -822,14 +968,13 @@ impl<'s> Parser<'s> {
                                 Container::Image(url_or_tag, ty)
                             }
                         }
-                        inline::Container::Autolink => {
+                        inline::Container::Autolink(url) => {
-                            let url: CowStr = inline.span.of(self.src).into();
                             let ty = if url.contains('@') {
                                 LinkType::Email
                             } else {
                                 LinkType::AutoLink
                             };
-                            Container::Link(url, ty)
+                            Container::Link(url.into(), ty)
                         }
                     };
                     if enter {
@@ -839,10 +984,8 @@ impl<'s> Parser<'s> {
                     }
                 }
                 inline::EventKind::Atom(a) => match a {
-                    inline::Atom::FootnoteReference => {
+                    inline::Atom::FootnoteReference { label } => Event::FootnoteReference(label),
-                        Event::FootnoteReference(inline.span.of(self.src))
+                    inline::Atom::Symbol(sym) => Event::Symbol(sym.into()),
-                    }
-                    inline::Atom::Symbol => Event::Symbol(inline.span.of(self.src).into()),
                     inline::Atom::Quote { ty, left } => match (ty, left) {
                         (inline::QuoteType::Single, true) => Event::LeftSingleQuote,
                         (inline::QuoteType::Single, false) => Event::RightSingleQuote,
@@ -861,48 +1004,58 @@ impl<'s> Parser<'s> {
                 inline::EventKind::Attributes { .. } | inline::EventKind::Placeholder => {
                     panic!("{:?}", inline)
                 }
-            }
+            };
+            (event, inline.span.into())
         })
     }
 
-    fn block(&mut self) -> Option<Event<'s>> {
+    fn block(&mut self) -> Option<(Event<'s>, Range<usize>)> {
-        while let Some(ev) = &mut self.tree.next() {
+        while let Some(mut ev) = &mut self.blocks.next() {
-            let content = ev.span.of(self.src);
             let event = match ev.kind {
-                tree::EventKind::Atom(a) => match a {
+                block::EventKind::Atom(a) => match a {
                     block::Atom::Blankline => Event::Blankline,
                     block::Atom::ThematicBreak => {
+                        if let Some(pos) = self.block_attributes_pos.take() {
+                            ev.span = Span::new(pos, ev.span.end());
+                        }
                         Event::ThematicBreak(self.block_attributes.take())
                     }
                     block::Atom::Attributes => {
-                        self.block_attributes.parse(content);
+                        if self.block_attributes_pos.is_none() {
+                            self.block_attributes_pos = Some(ev.span.start());
+                        }
+                        self.block_attributes.parse(ev.span.of(self.src));
                         continue;
                     }
                 },
-                tree::EventKind::Enter(c) | tree::EventKind::Exit(c) => {
+                block::EventKind::Enter(c) | block::EventKind::Exit(c) => {
-                    let enter = matches!(ev.kind, tree::EventKind::Enter(..));
+                    let enter = matches!(ev.kind, block::EventKind::Enter(..));
                     let cont = match c {
                         block::Node::Leaf(l) => {
                             self.inline_parser.reset();
                             match l {
                                 block::Leaf::Paragraph => Container::Paragraph,
-                                block::Leaf::Heading { has_section } => Container::Heading {
+                                block::Leaf::Heading {
-                                    level: content.len().try_into().unwrap(),
+                                    level,
+                                    has_section,
+                                    pos,
+                                } => Container::Heading {
+                                    level,
                                     has_section,
                                     id: self
                                         .pre_pass
-                                        .heading_id_by_location(ev.span.start())
+                                        .heading_id_by_location(pos)
                                         .unwrap_or_default()
                                         .to_string()
                                         .into(),
                                 },
                                 block::Leaf::DescriptionTerm => Container::DescriptionTerm,
-                                block::Leaf::CodeBlock => {
+                                block::Leaf::CodeBlock { language } => {
                                     self.verbatim = enter;
-                                    if let Some(format) = content.strip_prefix('=') {
+                                    if let Some(format) = language.strip_prefix('=') {
                                         Container::RawBlock { format }
                                     } else {
-                                        Container::CodeBlock { language: content }
+                                        Container::CodeBlock { language }
                                     }
                                 }
                                 block::Leaf::TableCell(alignment) => Container::TableCell {
@@ -910,16 +1063,20 @@ impl<'s> Parser<'s> {
                                     head: self.table_head_row,
                                 },
                                 block::Leaf::Caption => Container::Caption,
-                                block::Leaf::LinkDefinition => {
+                                block::Leaf::LinkDefinition { label } => {
-                                    Container::LinkDefinition { label: content }
+                                    self.verbatim = enter;
+                                    Container::LinkDefinition { label }
                                 }
                             }
                         }
                         block::Node::Container(c) => match c {
                             block::Container::Blockquote => Container::Blockquote,
-                            block::Container::Div => Container::Div { class: content },
+                            block::Container::Div { class } => Container::Div { class },
-                            block::Container::Footnote => Container::Footnote { label: content },
+                            block::Container::Footnote { label } => Container::Footnote { label },
-                            block::Container::List(block::ListKind { ty, tight }) => {
+                            block::Container::List {
+                                kind: block::ListKind { ty, tight },
+                                marker,
+                            } => {
                                 if matches!(ty, block::ListType::Description) {
                                     Container::DescriptionList
                                 } else {
@@ -927,9 +1084,8 @@ impl<'s> Parser<'s> {
                                         block::ListType::Unordered(..) => ListKind::Unordered,
                                         block::ListType::Task => ListKind::Task,
                                         block::ListType::Ordered(numbering, style) => {
-                                            let start = numbering
+                                            let start =
-                                                .parse_number(style.number(content))
+                                                numbering.parse_number(style.number(marker)).max(1);
-                                                .max(1);
                                             ListKind::Ordered {
                                                 numbering,
                                                 style,
@@ -941,12 +1097,12 @@ impl<'s> Parser<'s> {
                                     Container::List { kind, tight }
                                 }
                             }
-                            block::Container::ListItem(ty) => match ty {
+                            block::Container::ListItem(kind) => match kind {
-                                block::ListType::Task => Container::TaskListItem {
+                                block::ListItemKind::Task { checked } => {
-                                    checked: content.as_bytes()[3] != b' ',
+                                    Container::TaskListItem { checked }
-                                },
+                                }
-                                block::ListType::Description => Container::DescriptionDetails,
+                                block::ListItemKind::Description => Container::DescriptionDetails,
-                                _ => Container::ListItem,
+                                block::ListItemKind::List => Container::ListItem,
                             },
                             block::Container::Table => Container::Table,
                             block::Container::TableRow { head } => {
@@ -955,10 +1111,10 @@ impl<'s> Parser<'s> {
                                 }
                                 Container::TableRow { head }
                             }
-                            block::Container::Section => Container::Section {
+                            block::Container::Section { pos } => Container::Section {
                                 id: self
                                     .pre_pass
-                                    .heading_id_by_location(ev.span.start())
+                                    .heading_id_by_location(pos)
                                     .unwrap_or_default()
                                     .to_string()
                                     .into(),
@@ -966,32 +1122,63 @@ impl<'s> Parser<'s> {
                         },
                     };
                     if enter {
+                        if let Some(pos) = self.block_attributes_pos.take() {
+                            ev.span = Span::new(pos, ev.span.end());
+                        }
                         Event::Start(cont, self.block_attributes.take())
                     } else {
+                        self.block_attributes = Attributes::new();
+                        self.block_attributes_pos = None;
                         Event::End(cont)
                     }
                 }
-                tree::EventKind::Inline => {
+                block::EventKind::Inline => {
                     if self.verbatim {
-                        Event::Str(content.into())
+                        Event::Str(ev.span.of(self.src).into())
                     } else {
-                        self.inline_parser
+                        self.inline_parser.feed_line(
-                            .feed_line(ev.span, self.tree.branch_is_empty());
+                            ev.span,
-                        return self.next();
+                            !matches!(
+                                self.blocks.peek().map(|e| &e.kind),
+                                Some(block::EventKind::Inline),
+                            ),
+                        );
+                        return self.next_span();
                     }
                 }
+                block::EventKind::Stale => continue,
             };
-            return Some(event);
+            return Some((event, ev.span.into()));
         }
         None
     }
+
+    fn next_span(&mut self) -> Option<(Event<'s>, Range<usize>)> {
+        self.inline().or_else(|| self.block())
+    }
 }
 
 impl<'s> Iterator for Parser<'s> {
     type Item = Event<'s>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        self.inline().or_else(|| self.block())
+        self.next_span().map(|(e, _)| e)
+    }
+}
+
+/// An iterator that is identical to a [`Parser`], except that it also emits the location of each
+/// event within the input.
+///
+/// See the documentation of [`Parser::into_offset_iter`] for more information.
+pub struct OffsetIter<'s> {
+    parser: Parser<'s>,
+}
+
+impl<'s> Iterator for OffsetIter<'s> {
+    type Item = (Event<'s>, Range<usize>);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.parser.next_span()
     }
 }
 
@@ -1523,7 +1710,6 @@ mod test {
             Blankline,
             Start(LinkDefinition { label: "tag" }, Attributes::new()),
             Str("u".into()),
-            Softbreak,
             Str("rl".into()),
             End(LinkDefinition { label: "tag" }),
         );
@@ -1533,18 +1719,23 @@ mod test {
                 "\n",
                 "[tag]:\n",
                 " url\n",  //
+                " cont\n", //
             ),
             Start(Paragraph, Attributes::new()),
             Start(
-                Link("url".into(), LinkType::Span(SpanLinkType::Reference)),
+                Link("urlcont".into(), LinkType::Span(SpanLinkType::Reference)),
                 Attributes::new()
             ),
             Str("text".into()),
-            End(Link("url".into(), LinkType::Span(SpanLinkType::Reference))),
+            End(Link(
+                "urlcont".into(),
+                LinkType::Span(SpanLinkType::Reference)
+            )),
             End(Paragraph),
             Blankline,
             Start(LinkDefinition { label: "tag" }, Attributes::new()),
             Str("url".into()),
+            Str("cont".into()),
             End(LinkDefinition { label: "tag" }),
         );
     }

src/span.rs

@@ -4,6 +4,12 @@ pub struct Span {
     end: u32,
 }
 
+impl From<Span> for std::ops::Range<usize> {
+    fn from(span: Span) -> Self {
+        span.start()..span.end()
+    }
+}
+
 impl Span {
     pub fn new(start: usize, end: usize) -> Self {
         Self::by_len(start, end.checked_sub(start).unwrap())

src/tree.rs

@@ -1,427 +0,0 @@
-use crate::Span;
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum EventKind<C, A> {
-    Enter(C),
-    Inline,
-    Exit(C),
-    Atom(A),
-}
-
-#[derive(Debug)]
-pub struct Node<'a, C, A> {
-    pub index: NodeIndex,
-    pub elem: Element<'a, C, A>,
-    pub span: Span,
-}
-
-#[derive(Debug)]
-pub enum Element<'a, C, A> {
-    Container(&'a mut C),
-    Atom(&'a mut A),
-    Inline,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct Event<C, A> {
-    pub kind: EventKind<C, A>,
-    pub span: Span,
-}
-
-#[derive(Clone)]
-pub struct Tree<C: 'static, A: 'static> {
-    nodes: std::rc::Rc<[InternalNode<C, A>]>,
-    branch: Vec<NodeIndex>,
-    head: Option<NodeIndex>,
-}
-
-impl<C: Clone, A: Clone> Tree<C, A> {
-    /// Count number of direct children nodes.
-    pub fn count_children(&self) -> usize {
-        let mut head = self.head;
-        let mut count = 0;
-        while let Some(h) = head {
-            let n = &self.nodes[h.index()];
-            head = n.next;
-            count += 1;
-        }
-        count
-    }
-
-    /// Retrieve all inlines until the end of the current container. Panics if any upcoming node is
-    /// not an inline node.
-    pub fn take_inlines(&mut self) -> impl Iterator<Item = Span> + '_ {
-        let mut head = self.head.take();
-        std::iter::from_fn(move || {
-            head.take().map(|h| {
-                let n = &self.nodes[h.index()];
-                debug_assert!(matches!(n.kind, NodeKind::Inline));
-                head = n.next;
-                n.span
-            })
-        })
-    }
-
-    pub fn branch_is_empty(&self) -> bool {
-        matches!(self.head, None)
-    }
-}
-
-impl<C: Clone, A: Clone> Iterator for Tree<C, A> {
-    type Item = Event<C, A>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        if let Some(head) = self.head {
-            let n = &self.nodes[head.index()];
-            let kind = match &n.kind {
-                NodeKind::Root => unreachable!(),
-                NodeKind::Container(c, child) => {
-                    self.branch.push(head);
-                    self.head = *child;
-                    EventKind::Enter(c.clone())
-                }
-                NodeKind::Atom(a) => {
-                    self.head = n.next;
-                    EventKind::Atom(a.clone())
-                }
-                NodeKind::Inline => {
-                    self.head = n.next;
-                    EventKind::Inline
-                }
-            };
-            Some(Event { kind, span: n.span })
-        } else if let Some(block_ni) = self.branch.pop() {
-            let InternalNode { next, kind, span } = &self.nodes[block_ni.index()];
-            let kind = EventKind::Exit(kind.container().unwrap().clone());
-            self.head = *next;
-            Some(Event { kind, span: *span })
-        } else {
-            None
-        }
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct NodeIndex(std::num::NonZeroUsize);
-
-impl NodeIndex {
-    fn new(i: usize) -> Self {
-        debug_assert_ne!(i, usize::MAX);
-        Self((i + 1).try_into().unwrap())
-    }
-
-    fn root() -> Self {
-        Self::new(0)
-    }
-
-    fn index(self) -> usize {
-        usize::from(self.0) - 1
-    }
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-enum NodeKind<C, A> {
-    Root,
-    Container(C, Option<NodeIndex>),
-    Atom(A),
-    Inline,
-}
-
-#[derive(Debug, Clone)]
-struct InternalNode<C, A> {
-    span: Span,
-    kind: NodeKind<C, A>,
-    next: Option<NodeIndex>,
-}
-
-#[derive(Clone)]
-pub struct Builder<C, A> {
-    nodes: Vec<InternalNode<C, A>>,
-    branch: Vec<NodeIndex>,
-    head: Option<NodeIndex>,
-    depth: usize,
-}
-
-impl<C, A> NodeKind<C, A> {
-    fn child(&self) -> Option<NodeIndex> {
-        if let NodeKind::Container(_, child) = self {
-            *child
-        } else {
-            None
-        }
-    }
-
-    fn child_mut(&mut self) -> &mut Option<NodeIndex> {
-        if let NodeKind::Container(_, child) = self {
-            child
-        } else {
-            panic!()
-        }
-    }
-
-    fn container(&self) -> Option<&C> {
-        if let NodeKind::Container(c, _) = self {
-            Some(c)
-        } else {
-            None
-        }
-    }
-}
-
-impl<'a, C, A> From<&'a mut NodeKind<C, A>> for Element<'a, C, A> {
-    fn from(kind: &'a mut NodeKind<C, A>) -> Self {
-        match kind {
-            NodeKind::Root => unreachable!(),
-            NodeKind::Container(c, ..) => Element::Container(c),
-            NodeKind::Atom(a) => Element::Atom(a),
-            NodeKind::Inline => Element::Inline,
-        }
-    }
-}
-
-impl<C, A> Builder<C, A> {
-    pub(super) fn new() -> Self {
-        Builder {
-            nodes: vec![InternalNode {
-                span: Span::default(),
-                kind: NodeKind::Root,
-                next: None,
-            }],
-            branch: vec![],
-            head: Some(NodeIndex::root()),
-            depth: 0,
-        }
-    }
-
-    pub(super) fn atom(&mut self, a: A, span: Span) {
-        self.add_node(InternalNode {
-            span,
-            kind: NodeKind::Atom(a),
-            next: None,
-        });
-    }
-
-    pub(super) fn inline(&mut self, span: Span) {
-        self.add_node(InternalNode {
-            span,
-            kind: NodeKind::Inline,
-            next: None,
-        });
-    }
-
-    pub(super) fn enter(&mut self, c: C, span: Span) -> NodeIndex {
-        self.depth += 1;
-        self.add_node(InternalNode {
-            span,
-            kind: NodeKind::Container(c, None),
-            next: None,
-        })
-    }
-
-    pub(super) fn exit(&mut self) {
-        self.depth -= 1;
-        if let Some(head) = self.head.take() {
-            if matches!(self.nodes[head.index()].kind, NodeKind::Container(..)) {
-                self.branch.push(head);
-            }
-        } else {
-            let last = self.branch.pop();
-            debug_assert_ne!(last, None);
-        }
-    }
-
-    /// Exit and discard all the contents of the current container.
-    pub(super) fn exit_discard(&mut self) {
-        self.exit();
-        let exited = self.branch.pop().unwrap();
-        self.nodes.drain(exited.index()..);
-        let (prev, has_parent) = self.replace(exited, None);
-        if has_parent {
-            self.head = Some(prev);
-        } else {
-            self.branch.push(prev);
-        }
-    }
-
-    /// Swap the node and its children with either its parent or the node before.
-    pub fn swap_prev(&mut self, node: NodeIndex) {
-        let next = self.nodes[node.index()].next;
-        if let Some(n) = next {
-            self.replace(n, None);
-        }
-        let (prev, _) = self.replace(node, next);
-        self.replace(prev, Some(node));
-        self.nodes[node.index()].next = Some(prev);
-    }
-
-    /// Remove the specified node and its children.
-    pub fn remove(&mut self, node: NodeIndex) {
-        let next = self.nodes[node.index()].next;
-        self.replace(node, next);
-    }
-
-    pub(super) fn depth(&self) -> usize {
-        self.depth
-    }
-
-    pub(super) fn elem(&mut self, ni: NodeIndex) -> Element<C, A> {
-        match &mut self.nodes[ni.index()].kind {
-            NodeKind::Root => unreachable!(),
-            NodeKind::Container(c, ..) => Element::Container(c),
-            NodeKind::Atom(a) => Element::Atom(a),
-            NodeKind::Inline => Element::Inline,
-        }
-    }
-
-    /// Retrieve all children nodes for the specified node, in the order that they were added.
-    pub(super) fn children(&mut self, node: NodeIndex) -> impl Iterator<Item = Node<C, A>> {
-        // XXX assumes no modifications
-        let n = &self.nodes[node.index()];
-        let range = if let Some(start) = n.kind.child() {
-            start.index()..n.next.map_or(self.nodes.len(), NodeIndex::index)
-        } else {
-            0..0
-        };
-        range
-            .clone()
-            .map(NodeIndex::new)
-            .zip(self.nodes[range].iter_mut())
-            .map(|(index, n)| Node {
-                index,
-                elem: Element::from(&mut n.kind),
-                span: n.span,
-            })
-    }
-
-    pub(super) fn finish(self) -> Tree<C, A> {
-        debug_assert_eq!(self.depth, 0);
-        let head = self.nodes[NodeIndex::root().index()].next;
-        Tree {
-            nodes: self.nodes.into_boxed_slice().into(),
-            branch: Vec::new(),
-            head,
-        }
-    }
-
-    fn add_node(&mut self, node: InternalNode<C, A>) -> NodeIndex {
-        let ni = NodeIndex::new(self.nodes.len());
-        self.nodes.push(node);
-        if let Some(head_ni) = &mut self.head {
-            let mut head = &mut self.nodes[head_ni.index()];
-            match &mut head.kind {
-                NodeKind::Root | NodeKind::Inline | NodeKind::Atom(_) => {
-                    // set next pointer of previous node
-                    debug_assert_eq!(head.next, None);
-                    head.next = Some(ni);
-                }
-                NodeKind::Container(_, child) => {
-                    self.branch.push(*head_ni);
-                    // set child pointer of current container
-                    debug_assert_eq!(*child, None);
-                    *child = Some(ni);
-                }
-            }
-        } else if let Some(block) = self.branch.pop() {
-            let mut block = &mut self.nodes[block.index()];
-            debug_assert!(matches!(block.kind, NodeKind::Container(..)));
-            block.next = Some(ni);
-        } else {
-            panic!()
-        }
-        self.head = Some(ni);
-        ni
-    }
-
-    /// Remove the link from the node that points to the specified node. Optionally replace the
-    /// node with another node. Return the pointer node and whether it is a container or not.
-    fn replace(&mut self, node: NodeIndex, next: Option<NodeIndex>) -> (NodeIndex, bool) {
-        for (i, n) in self.nodes.iter_mut().enumerate().rev() {
-            let ni = NodeIndex::new(i);
-            if n.next == Some(node) {
-                n.next = next;
-                return (ni, false);
-            } else if n.kind.child() == Some(node) {
-                *n.kind.child_mut() = next;
-                return (ni, true);
-            }
-        }
-        panic!("node is never linked to")
-    }
-}
-
-impl<C: std::fmt::Debug + Clone + 'static, A: std::fmt::Debug + Clone + 'static> std::fmt::Debug
-    for Builder<C, A>
-{
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        self.clone().finish().fmt(f)
-    }
-}
-
-impl<C: std::fmt::Debug + Clone, A: std::fmt::Debug + Clone> std::fmt::Debug for Tree<C, A> {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        const INDENT: &str = "  ";
-        let mut level = 0;
-        writeln!(f)?;
-        for e in self.clone() {
-            let indent = INDENT.repeat(level);
-            match e.kind {
-                EventKind::Enter(c) => {
-                    write!(f, "{}{:?}", indent, c)?;
-                    level += 1;
-                }
-                EventKind::Inline => write!(f, "{}Inline", indent)?,
-                EventKind::Exit(..) => {
-                    level -= 1;
-                    continue;
-                }
-                EventKind::Atom(a) => write!(f, "{}{:?}", indent, a)?,
-            }
-            writeln!(f, " ({}:{})", e.span.start(), e.span.end())?;
-        }
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use crate::Span;
-
-    #[test]
-    fn fmt() {
-        let mut tree = super::Builder::new();
-        tree.enter(1, Span::new(0, 1));
-        tree.atom(11, Span::new(0, 1));
-        tree.atom(12, Span::new(0, 1));
-        tree.exit();
-        tree.enter(2, Span::new(1, 5));
-        tree.enter(21, Span::new(2, 5));
-        tree.enter(211, Span::new(3, 4));
-        tree.atom(2111, Span::new(3, 4));
-        tree.exit();
-        tree.exit();
-        tree.enter(22, Span::new(4, 5));
-        tree.atom(221, Span::new(4, 5));
-        tree.exit();
-        tree.exit();
-        tree.enter(3, Span::new(5, 6));
-        tree.atom(31, Span::new(5, 6));
-        tree.exit();
-        assert_eq!(
-            format!("{:?}", tree.finish()),
-            concat!(
-                "\n",
-                "1 (0:1)\n",
-                "  11 (0:1)\n",
-                "  12 (0:1)\n",
-                "2 (1:5)\n",
-                "  21 (2:5)\n",
-                "    211 (3:4)\n",
-                "      2111 (3:4)\n",
-                "  22 (4:5)\n",
-                "    221 (4:5)\n",
-                "3 (5:6)\n",
-                "  31 (5:6)\n",
-            )
-        );
-    }
-}

tests/afl/Cargo.toml

@@ -17,10 +17,6 @@ path = "src/main.rs"
 name = "parse"
 path = "src/parse.rs"
 
-[[bin]]
-name = "parse_balance"
-path = "src/parse_balance.rs"
-
 [[bin]]
 name = "html"
 path = "src/html.rs"

tests/afl/src/lib.rs

@@ -5,27 +5,66 @@ use html5ever::tendril::TendrilSink;
 use html5ever::tokenizer;
 use html5ever::tree_builder;
 
+/// Perform sanity checks on events.
 pub fn parse(data: &[u8]) {
     if let Ok(s) = std::str::from_utf8(data) {
-        jotdown::Parser::new(s).last();
+        let whitelist_whitespace = s.contains('{') && s.contains('}'); // attributes are outside events
-    }
-}
-
-/// Ensure containers are always balanced, i.e. opened and closed in correct order.
-pub fn parse_balance(data: &[u8]) {
-    if let Ok(s) = std::str::from_utf8(data) {
         let mut open = Vec::new();
-        for event in jotdown::Parser::new(s) {
+        let mut last = (jotdown::Event::Str("".into()), 0..0);
+        for (event, range) in jotdown::Parser::new(s).into_offset_iter() {
+            // no overlap, out of order
+            assert!(
+                last.1.end <= range.start
+                // block attributes may overlap with start event
+                || (
+                    matches!(last.0, jotdown::Event::Blankline)
+                    && (
+                        matches!(
+                            event,
+                            jotdown::Event::Start(ref cont, ..) if cont.is_block()
+                        )
+                        || matches!(event, jotdown::Event::ThematicBreak(..))
+                    )
+                )
+                // caption event is before table rows but src is after
+                || (
+                    matches!(
+                        last.0,
+                        jotdown::Event::Start(jotdown::Container::Caption, ..)
+                        | jotdown::Event::End(jotdown::Container::Caption)
+                    )
+                    && range.end <= last.1.start
+                ),
+                "{} > {} {:?} {:?}",
+                last.1.end,
+                range.start,
+                last.0,
+                event
+            );
+            last = (event.clone(), range.clone());
+            // range is valid unicode, does not cross char boundary
+            let _ = &s[range];
             match event {
                 jotdown::Event::Start(c, ..) => open.push(c.clone()),
-                jotdown::Event::End(c) => assert_eq!(open.pop().unwrap(), c),
+                jotdown::Event::End(c) => {
+                    // closes correct event
+                    assert_eq!(open.pop().unwrap(), c);
+                }
                 _ => {}
             }
         }
+        // no missing close
         assert_eq!(open, &[]);
+        // only whitespace after last event
+        assert!(
+            whitelist_whitespace || s[last.1.end..].chars().all(char::is_whitespace),
+            "non whitespace {:?}",
+            &s[last.1.end..],
+        );
     }
 }
 
+/// Validate rendered html output.
 pub fn html(data: &[u8]) {
     if data.iter().any(|i| *i == 0) {
         return;
@@ -132,9 +171,6 @@ impl<'a> tree_builder::TreeSink for Dom<'a> {
             "Found special tag while closing generic tag",
             "Formatting element not current node",
             "Formatting element not open",
-            // FIXME bug caused by empty table at end of list
-            "No matching tag to close",
-            "Unexpected open element while closing",
         ];
         if !whitelist.iter().any(|e| msg.starts_with(e)) {
             #[cfg(feature = "debug")]

tests/afl/src/main.rs

@@ -8,7 +8,6 @@ fn main() {
 
     let f = match target.as_str() {
         "parse" => jotdown_afl::parse,
-        "parse_balance" => jotdown_afl::parse_balance,
         "html" => jotdown_afl::html,
         _ => panic!("unknown target '{}'", target),
     };

tests/afl/src/parse_balance.rs

@@ -1,3 +0,0 @@
-fn main() {
-    afl::fuzz!(|data: &[u8]| { jotdown_afl::parse_balance(data) });
-}