PR #36 Emit link defs/footnotes as encountered

Merge branch 'footnote'

Makefile

@@ -29,7 +29,7 @@ check:
 suite:
 	git submodule update --init modules/djot.js
 	for f in $$(find modules/djot.js/test -name '*.test' | xargs basename -a); do \
-		ln -fs ../../modules/djot.js/test/$$f tests/suite/$$f; \
+		ln -fs ../../modules/djot.js/test/$$f tests/suite/djot_js_$$f; \
 	done
 	(cd tests/suite && make)
 	cargo test --features suite suite::
@@ -102,7 +102,7 @@ afl_tmin:
 clean:
 	cargo clean
 	git submodule deinit -f --all
-	rm -f tests/suite/*.test
+	find tests -type l -path 'tests/suite/*.test' -print0 | xargs -0 rm -f
 	(cd tests/suite && make clean)
 	rm -f tests/bench/*.dj
 	(cd tests/bench && make clean)

bench/input/block_footnotes.dj

@@ -0,0 +1,24 @@
+[^abc]: footnotes may appear before
+
+Some[^a] paragraph[^b] with[^c] a[^d] lot[^e] of[^f] footnotes[^g].
+
+[^a]: A typical footnote may have a single paragraph.
+[^b]: A typical footnote may have a single paragraph.
+[^c]: A typical footnote may have a single paragraph.
+[^d]: A typical footnote may have a single paragraph.
+[^e]: A typical footnote may have a single paragraph.
+[^f]: A typical footnote may have a single paragraph.
+[^g]: Footnotes may also be
+
+    - long and,
+    - contain multiple block elements.
+
+    such as
+
+    > blockquotes.
+
+Footnote [^labels may be long but not multi line]
+
+[^labels may be long but not multi line]: longer than the footnote..
+
+the reference[^abc] to it.

src/html.rs

@@ -5,61 +5,93 @@ use crate::Container;
 use crate::Event;
 use crate::LinkType;
 use crate::ListKind;
+use crate::Map;
 use crate::OrderedListNumbering::*;
 use crate::Render;
 use crate::SpanLinkType;
 
+#[derive(Default)]
+pub struct Renderer {}
+
+impl Render for Renderer {
+    fn push<'s, I, W>(&self, mut events: I, mut out: W) -> std::fmt::Result
+    where
+        I: Iterator<Item = Event<'s>>,
+        W: std::fmt::Write,
+    {
+        let mut w = Writer::default();
+        events.try_for_each(|e| w.render_event(&e, &mut out))?;
+        w.render_epilogue(&mut out)
+    }
+
+    fn push_borrowed<'s, E, I, W>(&self, mut events: I, mut out: W) -> std::fmt::Result
+    where
+        E: AsRef<Event<'s>>,
+        I: Iterator<Item = E>,
+        W: std::fmt::Write,
+    {
+        let mut w = Writer::default();
+        events.try_for_each(|e| w.render_event(e.as_ref(), &mut out))?;
+        w.render_epilogue(&mut out)
+    }
+}
+
 enum Raw {
     None,
     Html,
     Other,
 }
 
-pub struct Renderer {
+impl Default for Raw {
-    raw: Raw,
-    img_alt_text: usize,
-    list_tightness: Vec<bool>,
-    encountered_footnote: bool,
-    footnote_number: Option<std::num::NonZeroUsize>,
-    first_line: bool,
-    close_para: bool,
-}
-
-impl Default for Renderer {
     fn default() -> Self {
-        Self {
+        Self::None
-            raw: Raw::None,
-            img_alt_text: 0,
-            list_tightness: Vec::new(),
-            encountered_footnote: false,
-            footnote_number: None,
-            first_line: true,
-            close_para: false,
-        }
     }
 }
 
-impl Render for Renderer {
+#[derive(Default)]
-    fn render_event<'s, W>(&mut self, e: &Event<'s>, mut out: W) -> std::fmt::Result
+struct Writer<'s> {
+    raw: Raw,
+    img_alt_text: usize,
+    list_tightness: Vec<bool>,
+    not_first_line: bool,
+    ignore: bool,
+    footnotes: Footnotes<'s>,
+}
+
+impl<'s> Writer<'s> {
+    fn render_event<W>(&mut self, e: &Event<'s>, mut out: W) -> std::fmt::Result
     where
         W: std::fmt::Write,
     {
-        if matches!(&e, Event::Blankline | Event::Escape) {
+        if let Event::Start(Container::Footnote { label }, ..) = e {
+            self.footnotes.start(label, Vec::new());
+            return Ok(());
+        } else if let Some(events) = self.footnotes.current() {
+            if matches!(e, Event::End(Container::Footnote { .. })) {
+                self.footnotes.end();
+            } else {
+                events.push(e.clone());
+            }
             return Ok(());
         }
 
-        let close_para = self.close_para;
+        if matches!(&e, Event::Start(Container::LinkDefinition { .. }, ..)) {
-        if close_para {
+            self.ignore = true;
-            self.close_para = false;
+            return Ok(());
-            if !matches!(&e, Event::End(Container::Footnote { .. })) {
+        }
-                // no need to add href before para close
+
-                out.write_str("</p>")?;
+        if matches!(&e, Event::End(Container::LinkDefinition { .. })) {
-            }
+            self.ignore = false;
+            return Ok(());
+        }
+
+        if self.ignore {
+            return Ok(());
         }
 
         match e {
             Event::Start(c, attrs) => {
-                if c.is_block() && !self.first_line {
+                if c.is_block() && self.not_first_line {
                     out.write_char('\n')?;
                 }
                 if self.img_alt_text > 0 && !matches!(c, Container::Image(..)) {
@@ -95,16 +127,7 @@ impl Render for Renderer {
                     }
                     Container::DescriptionList => out.write_str("<dl")?,
                     Container::DescriptionDetails => out.write_str("<dd")?,
-                    Container::Footnote { number, .. } => {
+                    Container::Footnote { .. } => unreachable!(),
-                        debug_assert!(self.footnote_number.is_none());
-                        self.footnote_number = Some((*number).try_into().unwrap());
-                        if !self.encountered_footnote {
-                            self.encountered_footnote = true;
-                            out.write_str("<section role=\"doc-endnotes\">\n<hr>\n<ol>\n")?;
-                        }
-                        write!(out, "<li id=\"fn{}\">", number)?;
-                        return Ok(());
-                    }
                     Container::Table => out.write_str("<table")?,
                     Container::TableRow { .. } => out.write_str("<tr")?,
                     Container::Section { .. } => out.write_str("<section")?,
@@ -158,6 +181,7 @@ impl Render for Renderer {
                     Container::Strong => out.write_str("<strong")?,
                     Container::Emphasis => out.write_str("<em")?,
                     Container::Mark => out.write_str("<mark")?,
+                    Container::LinkDefinition { .. } => return Ok(()),
                 }
 
                 for (a, v) in attrs.iter().filter(|(a, _)| *a != "class") {
@@ -263,7 +287,7 @@ impl Render for Renderer {
                 }
             }
             Event::End(c) => {
-                if c.is_block_container() && !matches!(c, Container::Footnote { .. }) {
+                if c.is_block_container() {
                     out.write_char('\n')?;
                 }
                 if self.img_alt_text > 0 && !matches!(c, Container::Image(..)) {
@@ -287,19 +311,7 @@ impl Render for Renderer {
                     }
                     Container::DescriptionList => out.write_str("</dl>")?,
                     Container::DescriptionDetails => out.write_str("</dd>")?,
-                    Container::Footnote { number, .. } => {
+                    Container::Footnote { .. } => unreachable!(),
-                        if !close_para {
-                            // create a new paragraph
-                            out.write_str("\n<p>")?;
-                        }
-                        write!(
-                            out,
-                            r##"<a href="#fnref{}" role="doc-backlink">↩︎︎</a></p>"##,
-                            number,
-                        )?;
-                        out.write_str("\n</li>")?;
-                        self.footnote_number = None;
-                    }
                     Container::Table => out.write_str("</table>")?,
                     Container::TableRow { .. } => out.write_str("</tr>")?,
                     Container::Section { .. } => out.write_str("</section>")?,
@@ -308,10 +320,8 @@ impl Render for Renderer {
                         if matches!(self.list_tightness.last(), Some(true)) {
                             return Ok(());
                         }
-                        if self.footnote_number.is_none() {
+                        if !self.footnotes.in_epilogue() {
                             out.write_str("</p>")?;
-                        } else {
-                            self.close_para = true;
                         }
                     }
                     Container::Heading { level, .. } => write!(out, "</h{}>", level)?,
@@ -350,6 +360,7 @@ impl Render for Renderer {
                     Container::Strong => out.write_str("</strong>")?,
                     Container::Emphasis => out.write_str("</em>")?,
                     Container::Mark => out.write_str("</mark>")?,
+                    Container::LinkDefinition { .. } => unreachable!(),
                 }
             }
             Event::Str(s) => match self.raw {
@@ -358,7 +369,8 @@ impl Render for Renderer {
                 Raw::Html => out.write_str(s)?,
                 Raw::Other => {}
             },
-            Event::FootnoteReference(_tag, number) => {
+            Event::FootnoteReference(label) => {
+                let number = self.footnotes.reference(label);
                 if self.img_alt_text == 0 {
                     write!(
                         out,
@@ -378,7 +390,7 @@ impl Render for Renderer {
             Event::NonBreakingSpace => out.write_str("&nbsp;")?,
             Event::Hardbreak => out.write_str("<br>\n")?,
             Event::Softbreak => out.write_char('\n')?,
-            Event::Escape | Event::Blankline => unreachable!("filtered out"),
+            Event::Escape | Event::Blankline => {}
             Event::ThematicBreak(attrs) => {
                 out.write_str("\n<hr")?;
                 for (a, v) in attrs.iter() {
@@ -389,7 +401,7 @@ impl Render for Renderer {
                 out.write_str(">")?;
             }
         }
-        self.first_line = false;
+        self.not_first_line = true;
 
         Ok(())
     }
@@ -398,9 +410,41 @@ impl Render for Renderer {
     where
         W: std::fmt::Write,
     {
-        if self.encountered_footnote {
+        if self.footnotes.reference_encountered() {
+            out.write_str("\n<section role=\"doc-endnotes\">\n<hr>\n<ol>")?;
+
+            while let Some((number, events)) = self.footnotes.next() {
+                write!(out, "\n<li id=\"fn{}\">", number)?;
+
+                let mut unclosed_para = false;
+                for e in events.iter().flatten() {
+                    if matches!(&e, Event::Blankline | Event::Escape) {
+                        continue;
+                    }
+                    if unclosed_para {
+                        // not a footnote, so no need to add href before para close
+                        out.write_str("</p>")?;
+                    }
+                    self.render_event(e, &mut out)?;
+                    unclosed_para = matches!(e, Event::End(Container::Paragraph { .. }))
+                        && !matches!(self.list_tightness.last(), Some(true));
+                }
+                if !unclosed_para {
+                    // create a new paragraph
+                    out.write_str("\n<p>")?;
+                }
+                write!(
+                    out,
+                    r##"<a href="#fnref{}" role="doc-backlink">↩︎︎</a></p>"##,
+                    number,
+                )?;
+
+                out.write_str("\n</li>")?;
+            }
+
             out.write_str("\n</ol>\n</section>")?;
         }
+
         out.write_char('\n')?;
 
         Ok(())
@@ -445,3 +489,73 @@ where
     }
     out.write_str(s)
 }
+
+/// Helper to aggregate footnotes for rendering at the end of the document. It will cache footnote
+/// events until they should be emitted at the end.
+///
+/// When footnotes should be rendered, they can be pulled with the [`Footnotes::next`] function in
+/// the order they were first referenced.
+#[derive(Default)]
+struct Footnotes<'s> {
+    /// Stack of current open footnotes, with label and staging buffer.
+    open: Vec<(&'s str, Vec<Event<'s>>)>,
+    /// Footnote references in the order they were first encountered.
+    references: Vec<&'s str>,
+    /// Events for each footnote.
+    events: Map<&'s str, Vec<Event<'s>>>,
+    /// Number of last footnote that was emitted.
+    number: usize,
+}
+
+impl<'s> Footnotes<'s> {
+    /// Returns `true` if any reference has been encountered.
+    fn reference_encountered(&self) -> bool {
+        !self.references.is_empty()
+    }
+
+    /// Returns `true` if within the epilogue, i.e. if any footnotes have been pulled.
+    fn in_epilogue(&self) -> bool {
+        self.number > 0
+    }
+
+    /// Add a footnote reference.
+    fn reference(&mut self, label: &'s str) -> usize {
+        self.references
+            .iter()
+            .position(|t| *t == label)
+            .map_or_else(
+                || {
+                    self.references.push(label);
+                    self.references.len()
+                },
+                |i| i + 1,
+            )
+    }
+
+    /// Start aggregating a footnote.
+    fn start(&mut self, label: &'s str, events: Vec<Event<'s>>) {
+        self.open.push((label, events));
+    }
+
+    /// Obtain the current (most recently started) footnote.
+    fn current(&mut self) -> Option<&mut Vec<Event<'s>>> {
+        self.open.last_mut().map(|(_, e)| e)
+    }
+
+    /// End the current (most recently started) footnote.
+    fn end(&mut self) {
+        let (label, stage) = self.open.pop().unwrap();
+        self.events.insert(label, stage);
+    }
+}
+
+impl<'s> Iterator for Footnotes<'s> {
+    type Item = (usize, Option<Vec<Event<'s>>>);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.references.get(self.number).map(|label| {
+            self.number += 1;
+            (self.number, self.events.remove(label))
+        })
+    }
+}

src/lib.rs

@@ -75,11 +75,6 @@ type CowStr<'s> = std::borrow::Cow<'s, str>;
 /// If ownership of the [`Event`]s cannot be given to the renderer, use [`Render::push_borrowed`]
 /// or [`Render::write_borrowed`].
 ///
-/// An implementor needs to at least implement the [`Render::render_event`] function that renders a
-/// single event to the output. If anything needs to be rendered at the beginning or end of the
-/// output, the [`Render::render_prologue`] and [`Render::render_epilogue`] can be implemented as
-/// well.
-///
 /// # Examples
 ///
 /// Push to a [`String`] (implements [`std::fmt::Write`]):
@@ -90,7 +85,7 @@ type CowStr<'s> = std::borrow::Cow<'s, str>;
 /// # use jotdown::Render;
 /// # let events = std::iter::empty();
 /// let mut output = String::new();
-/// let mut renderer = jotdown::html::Renderer::default();
+/// let renderer = jotdown::html::Renderer::default();
 /// renderer.push(events, &mut output);
 /// # }
 /// ```
@@ -103,54 +98,22 @@ type CowStr<'s> = std::borrow::Cow<'s, str>;
 /// # use jotdown::Render;
 /// # let events = std::iter::empty();
 /// let mut out = std::io::BufWriter::new(std::io::stdout());
-/// let mut renderer = jotdown::html::Renderer::default();
+/// let renderer = jotdown::html::Renderer::default();
 /// renderer.write(events, &mut out).unwrap();
 /// # }
 /// ```
 pub trait Render {
-    /// Render a single event.
-    fn render_event<'s, W>(&mut self, e: &Event<'s>, out: W) -> std::fmt::Result
-    where
-        W: std::fmt::Write;
-
-    /// Render something before any events have been provided.
-    ///
-    /// This does nothing by default, but an implementation may choose to prepend data at the
-    /// beginning of the output if needed.
-    fn render_prologue<W>(&mut self, _out: W) -> std::fmt::Result
-    where
-        W: std::fmt::Write,
-    {
-        Ok(())
-    }
-
-    /// Render something after all events have been provided.
-    ///
-    /// This does nothing by default, but an implementation may choose to append extra data at the
-    /// end of the output if needed.
-    fn render_epilogue<W>(&mut self, _out: W) -> std::fmt::Result
-    where
-        W: std::fmt::Write,
-    {
-        Ok(())
-    }
-
     /// Push owned [`Event`]s to a unicode-accepting buffer or stream.
-    fn push<'s, I, W>(&mut self, mut events: I, mut out: W) -> fmt::Result
+    fn push<'s, I, W>(&self, events: I, out: W) -> fmt::Result
     where
         I: Iterator<Item = Event<'s>>,
-        W: fmt::Write,
+        W: fmt::Write;
-    {
-        self.render_prologue(&mut out)?;
-        events.try_for_each(|e| self.render_event(&e, &mut out))?;
-        self.render_epilogue(&mut out)
-    }
 
     /// Write owned [`Event`]s to a byte sink, encoded as UTF-8.
     ///
     /// NOTE: This performs many small writes, so IO writes should be buffered with e.g.
     /// [`std::io::BufWriter`].
-    fn write<'s, I, W>(&mut self, events: I, out: W) -> io::Result<()>
+    fn write<'s, I, W>(&self, events: I, out: W) -> io::Result<()>
     where
         I: Iterator<Item = Event<'s>>,
         W: io::Write,
@@ -177,26 +140,21 @@ pub trait Render {
     /// # use jotdown::Render;
     /// # let events: &[jotdown::Event] = &[];
     /// let mut output = String::new();
-    /// let mut renderer = jotdown::html::Renderer::default();
+    /// let renderer = jotdown::html::Renderer::default();
     /// renderer.push_borrowed(events.iter(), &mut output);
     /// # }
     /// ```
-    fn push_borrowed<'s, E, I, W>(&mut self, mut events: I, mut out: W) -> fmt::Result
+    fn push_borrowed<'s, E, I, W>(&self, events: I, out: W) -> fmt::Result
     where
         E: AsRef<Event<'s>>,
         I: Iterator<Item = E>,
-        W: fmt::Write,
+        W: fmt::Write;
-    {
-        self.render_prologue(&mut out)?;
-        events.try_for_each(|e| self.render_event(e.as_ref(), &mut out))?;
-        self.render_epilogue(&mut out)
-    }
 
     /// Write borrowed [`Event`]s to a byte sink, encoded as UTF-8.
     ///
     /// NOTE: This performs many small writes, so IO writes should be buffered with e.g.
     /// [`std::io::BufWriter`].
-    fn write_borrowed<'s, E, I, W>(&mut self, events: I, out: W) -> io::Result<()>
+    fn write_borrowed<'s, E, I, W>(&self, events: I, out: W) -> io::Result<()>
     where
         E: AsRef<Event<'s>>,
         I: Iterator<Item = E>,
@@ -251,7 +209,7 @@ pub enum Event<'s> {
     /// A string object, text only.
     Str(CowStr<'s>),
     /// A footnote reference.
-    FootnoteReference(&'s str, usize),
+    FootnoteReference(&'s str),
     /// A symbol, by default rendered literally but may be treated specially.
     Symbol(CowStr<'s>),
     /// Left single quotation mark.
@@ -304,7 +262,7 @@ pub enum Container<'s> {
     /// Details describing a term within a description list.
     DescriptionDetails,
     /// A footnote definition.
-    Footnote { tag: &'s str, number: usize },
+    Footnote { label: &'s str },
     /// A table element.
     Table,
     /// A row element of a table.
@@ -327,6 +285,8 @@ pub enum Container<'s> {
     Caption,
     /// A term within a description list.
     DescriptionTerm,
+    /// A link definition.
+    LinkDefinition { label: &'s str },
     /// A block with raw markup for a specific output format.
     RawBlock { format: &'s str },
     /// A block with code in a specific language.
@@ -381,6 +341,7 @@ impl<'s> Container<'s> {
             | Self::TableCell { .. }
             | Self::Caption
             | Self::DescriptionTerm
+            | Self::LinkDefinition { .. }
             | Self::RawBlock { .. }
             | Self::CodeBlock { .. } => true,
             Self::Span
@@ -419,6 +380,7 @@ impl<'s> Container<'s> {
             | Self::TableCell { .. }
             | Self::Caption
             | Self::DescriptionTerm
+            | Self::LinkDefinition { .. }
             | Self::RawBlock { .. }
             | Self::CodeBlock { .. }
             | Self::Span
@@ -607,15 +569,6 @@ pub struct Parser<'s> {
     /// Currently within a verbatim code block.
     verbatim: bool,
 
-    /// Footnote references in the order they were encountered, without duplicates.
-    footnote_references: Vec<&'s str>,
-    /// Cache of footnotes to emit at the end.
-    footnotes: Map<&'s str, block::Tree>,
-    /// Next or current footnote being parsed and emitted.
-    footnote_index: usize,
-    /// Currently within a footnote.
-    footnote_active: bool,
-
     /// Inline parser.
     inline_parser: inline::Parser<'s>,
 }
@@ -793,10 +746,6 @@ impl<'s> Parser<'s> {
             block_attributes: Attributes::new(),
             table_head_row: false,
             verbatim: false,
-            footnote_references: Vec::new(),
-            footnotes: Map::new(),
-            footnote_index: 0,
-            footnote_active: false,
             inline_parser,
         }
     }
@@ -885,19 +834,7 @@ impl<'s> Parser<'s> {
                 }
                 inline::EventKind::Atom(a) => match a {
                     inline::Atom::FootnoteReference => {
-                        let tag = inline.span.of(self.src);
+                        Event::FootnoteReference(inline.span.of(self.src))
-                        let number = self
-                            .footnote_references
-                            .iter()
-                            .position(|t| *t == tag)
-                            .map_or_else(
-                                || {
-                                    self.footnote_references.push(tag);
-                                    self.footnote_references.len()
-                                },
-                                |i| i + 1,
-                            );
-                        Event::FootnoteReference(inline.span.of(self.src), number)
                     }
                     inline::Atom::Symbol => Event::Symbol(inline.span.of(self.src).into()),
                     inline::Atom::Quote { ty, left } => match (ty, left) {
@@ -941,14 +878,6 @@ impl<'s> Parser<'s> {
                     let cont = match c {
                         block::Node::Leaf(l) => {
                             self.inline_parser.reset();
-                            if matches!(l, block::Leaf::LinkDefinition) {
-                                // ignore link definitions
-                                if enter {
-                                    self.tree.take_inlines().last();
-                                }
-                                self.block_attributes = Attributes::new();
-                                continue;
-                            }
                             match l {
                                 block::Leaf::Paragraph => Container::Paragraph,
                                 block::Leaf::Heading { has_section } => Container::Heading {
@@ -977,7 +906,9 @@ impl<'s> Parser<'s> {
                                     head: self.table_head_row,
                                 },
                                 block::Leaf::Caption => Container::Caption,
-                                block::Leaf::LinkDefinition => unreachable!(),
+                                block::Leaf::LinkDefinition => {
+                                    Container::LinkDefinition { label: content }
+                                }
                             }
                         }
                         block::Node::Container(c) => match c {
@@ -985,12 +916,7 @@ impl<'s> Parser<'s> {
                             block::Container::Div { .. } => Container::Div {
                                 class: (!ev.span.is_empty()).then(|| content),
                             },
-                            block::Container::Footnote => {
+                            block::Container::Footnote => Container::Footnote { label: content },
-                                debug_assert!(enter);
-                                self.footnotes.insert(content, self.tree.take_branch());
-                                self.block_attributes = Attributes::new();
-                                continue;
-                            }
                             block::Container::List(block::ListKind { ty, tight }) => {
                                 if matches!(ty, block::ListType::Description) {
                                     Container::DescriptionList
@@ -1057,43 +983,13 @@ impl<'s> Parser<'s> {
         }
         None
     }
-
-    fn footnote(&mut self) -> Option<Event<'s>> {
-        if self.footnote_active {
-            let tag = self.footnote_references.get(self.footnote_index).unwrap();
-            self.footnote_index += 1;
-            self.footnote_active = false;
-            Some(Event::End(Container::Footnote {
-                tag,
-                number: self.footnote_index,
-            }))
-        } else if let Some(tag) = self.footnote_references.get(self.footnote_index) {
-            self.tree = self
-                .footnotes
-                .remove(tag)
-                .unwrap_or_else(block::Tree::empty);
-            self.footnote_active = true;
-
-            Some(Event::Start(
-                Container::Footnote {
-                    tag,
-                    number: self.footnote_index + 1,
-                },
-                Attributes::new(),
-            ))
-        } else {
-            None
-        }
-    }
 }
 
 impl<'s> Iterator for Parser<'s> {
     type Item = Event<'s>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        self.inline()
+        self.inline().or_else(|| self.block())
-            .or_else(|| self.block())
-            .or_else(|| self.footnote())
     }
 }
 
@@ -1418,6 +1314,9 @@ mod test {
             End(Link("url".into(), LinkType::Span(SpanLinkType::Reference))),
             End(Paragraph),
             Blankline,
+            Start(LinkDefinition { label: "tag" }, Attributes::new()),
+            Str("url".into()),
+            End(LinkDefinition { label: "tag" }),
         );
         test_parse!(
             concat!(
@@ -1434,6 +1333,9 @@ mod test {
             End(Image("url".into(), SpanLinkType::Reference)),
             End(Paragraph),
             Blankline,
+            Start(LinkDefinition { label: "tag" }, Attributes::new()),
+            Str("url".into()),
+            End(LinkDefinition { label: "tag" }),
         );
     }
 
@@ -1483,6 +1385,9 @@ mod test {
             End(Paragraph),
             End(Blockquote),
             Blankline,
+            Start(LinkDefinition { label: "a b" }, Attributes::new()),
+            Str("url".into()),
+            End(LinkDefinition { label: "a b" }),
         );
     }
 
@@ -1504,6 +1409,11 @@ mod test {
             End(Link("url".into(), LinkType::Span(SpanLinkType::Reference))),
             End(Paragraph),
             Blankline,
+            Start(LinkDefinition { label: "tag" }, Attributes::new()),
+            Str("u".into()),
+            Softbreak,
+            Str("rl".into()),
+            End(LinkDefinition { label: "tag" }),
         );
         test_parse!(
             concat!(
@@ -1521,6 +1431,9 @@ mod test {
             End(Link("url".into(), LinkType::Span(SpanLinkType::Reference))),
             End(Paragraph),
             Blankline,
+            Start(LinkDefinition { label: "tag" }, Attributes::new()),
+            Str("url".into()),
+            End(LinkDefinition { label: "tag" }),
         );
     }
 
@@ -1543,6 +1456,12 @@ mod test {
             End(Link("url".into(), LinkType::Span(SpanLinkType::Reference))),
             End(Paragraph),
             Blankline,
+            Start(
+                LinkDefinition { label: "tag" },
+                [("a", "b")].into_iter().collect()
+            ),
+            Str("url".into()),
+            End(LinkDefinition { label: "tag" }),
             Start(Paragraph, Attributes::new()),
             Str("para".into()),
             End(Paragraph),
@@ -1584,43 +1503,10 @@ mod test {
         test_parse!(
             "[^a][^b][^c]",
             Start(Paragraph, Attributes::new()),
-            FootnoteReference("a", 1),
+            FootnoteReference("a"),
-            FootnoteReference("b", 2),
+            FootnoteReference("b"),
-            FootnoteReference("c", 3),
+            FootnoteReference("c"),
             End(Paragraph),
-            Start(
-                Footnote {
-                    tag: "a",
-                    number: 1
-                },
-                Attributes::new()
-            ),
-            End(Footnote {
-                tag: "a",
-                number: 1
-            }),
-            Start(
-                Footnote {
-                    tag: "b",
-                    number: 2
-                },
-                Attributes::new()
-            ),
-            End(Footnote {
-                tag: "b",
-                number: 2
-            }),
-            Start(
-                Footnote {
-                    tag: "c",
-                    number: 3
-                },
-                Attributes::new()
-            ),
-            End(Footnote {
-                tag: "c",
-                number: 3
-            }),
         );
     }
 
@@ -1629,23 +1515,14 @@ mod test {
         test_parse!(
             "[^a]\n\n[^a]: a\n",
             Start(Paragraph, Attributes::new()),
-            FootnoteReference("a", 1),
+            FootnoteReference("a"),
             End(Paragraph),
             Blankline,
-            Start(
+            Start(Footnote { label: "a" }, Attributes::new()),
-                Footnote {
-                    tag: "a",
-                    number: 1
-                },
-                Attributes::new()
-            ),
             Start(Paragraph, Attributes::new()),
             Str("a".into()),
             End(Paragraph),
-            End(Footnote {
+            End(Footnote { label: "a" }),
-                tag: "a",
-                number: 1
-            }),
         );
     }
 
@@ -1660,16 +1537,10 @@ mod test {
                 " def", //
             ),
             Start(Paragraph, Attributes::new()),
-            FootnoteReference("a", 1),
+            FootnoteReference("a"),
             End(Paragraph),
             Blankline,
-            Start(
+            Start(Footnote { label: "a" }, Attributes::new()),
-                Footnote {
-                    tag: "a",
-                    number: 1
-                },
-                Attributes::new()
-            ),
             Start(Paragraph, Attributes::new()),
             Str("abc".into()),
             End(Paragraph),
@@ -1677,10 +1548,7 @@ mod test {
             Start(Paragraph, Attributes::new()),
             Str("def".into()),
             End(Paragraph),
-            End(Footnote {
+            End(Footnote { label: "a" }),
-                tag: "a",
-                number: 1
-            }),
         );
     }
 
@@ -1694,26 +1562,17 @@ mod test {
                 "para\n", //
             ),
             Start(Paragraph, Attributes::new()),
-            FootnoteReference("a", 1),
+            FootnoteReference("a"),
             End(Paragraph),
             Blankline,
-            Start(Paragraph, Attributes::new()),
+            Start(Footnote { label: "a" }, Attributes::new()),
-            Str("para".into()),
-            End(Paragraph),
-            Start(
-                Footnote {
-                    tag: "a",
-                    number: 1
-                },
-                Attributes::new()
-            ),
             Start(Paragraph, Attributes::new()),
             Str("note".into()),
             End(Paragraph),
-            End(Footnote {
+            End(Footnote { label: "a" }),
-                tag: "a",
+            Start(Paragraph, Attributes::new()),
-                number: 1
+            Str("para".into()),
-            }),
+            End(Paragraph),
         );
     }
 

src/main.rs

@@ -68,7 +68,7 @@ fn run() -> Result<(), std::io::Error> {
     };
 
     let parser = jotdown::Parser::new(&content);
-    let mut renderer = jotdown::html::Renderer::default();
+    let renderer = jotdown::html::Renderer::default();
 
     match app.output {
         Some(path) => renderer.write(parser, File::create(path)?)?,

src/tree.rs

@@ -36,14 +36,6 @@ pub struct Tree<C: 'static, A: 'static> {
 }
 
 impl<C: Clone, A: Clone> Tree<C, A> {
-    pub fn empty() -> Self {
-        Self {
-            nodes: vec![].into_boxed_slice().into(),
-            branch: Vec::new(),
-            head: None,
-        }
-    }
-
     /// Count number of direct children nodes.
     pub fn count_children(&self) -> usize {
         let mut head = self.head;
@@ -56,22 +48,6 @@ impl<C: Clone, A: Clone> Tree<C, A> {
         count
     }
 
-    /// Split off the remaining part of the current branch. The returned [`Tree`] will continue on
-    /// the branch, this [`Tree`] will skip over the current branch.
-    pub fn take_branch(&mut self) -> Self {
-        let head = self.head.take();
-        self.head = self.branch.pop();
-        if let Some(h) = self.head {
-            let n = &self.nodes[h.index()];
-            self.head = n.next;
-        }
-        Self {
-            nodes: self.nodes.clone(),
-            branch: Vec::new(),
-            head,
-        }
-    }
-
     /// 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> + '_ {
@@ -410,9 +386,6 @@ impl<C: std::fmt::Debug + Clone, A: std::fmt::Debug + Clone> std::fmt::Debug for
 mod test {
     use crate::Span;
 
-    use super::Event;
-    use super::EventKind;
-
     #[test]
     fn fmt() {
         let mut tree = super::Builder::new();
@@ -451,81 +424,4 @@ mod test {
             )
         );
     }
-
-    #[test]
-    fn branch_take_branch() {
-        let mut b = super::Builder::new();
-        let sp = Span::new(0, 0);
-        b.enter(1, sp);
-        b.atom(11, sp);
-        b.exit();
-        b.enter(2, sp);
-        b.enter(21, sp);
-        b.atom(211, sp);
-        b.exit();
-        b.exit();
-        b.enter(3, sp);
-        b.atom(31, sp);
-        b.exit();
-        let mut tree = b.finish();
-
-        assert_eq!(
-            (&mut tree).take(3).collect::<Vec<_>>(),
-            &[
-                Event {
-                    kind: EventKind::Enter(1),
-                    span: sp
-                },
-                Event {
-                    kind: EventKind::Atom(11),
-                    span: sp
-                },
-                Event {
-                    kind: EventKind::Exit(1),
-                    span: sp
-                },
-            ]
-        );
-        assert_eq!(
-            tree.next(),
-            Some(Event {
-                kind: EventKind::Enter(2),
-                span: sp
-            })
-        );
-        assert_eq!(
-            tree.take_branch().collect::<Vec<_>>(),
-            &[
-                Event {
-                    kind: EventKind::Enter(21),
-                    span: sp
-                },
-                Event {
-                    kind: EventKind::Atom(211),
-                    span: sp
-                },
-                Event {
-                    kind: EventKind::Exit(21),
-                    span: sp
-                },
-            ]
-        );
-        assert_eq!(
-            tree.collect::<Vec<_>>(),
-            &[
-                Event {
-                    kind: EventKind::Enter(3),
-                    span: sp
-                },
-                Event {
-                    kind: EventKind::Atom(31),
-                    span: sp
-                },
-                Event {
-                    kind: EventKind::Exit(3),
-                    span: sp
-                },
-            ]
-        );
-    }
 }

tests/suite/Makefile

@@ -5,9 +5,9 @@
 TEST=$(shell find . -name '*.test' | sort)
 TEST_RS=${TEST:.test=.rs}
 
-BLACKLIST += filters # lua filters not implemented
+BLACKLIST += djot_js_filters # lua filters not implemented
-BLACKLIST += symb # uses ast
+BLACKLIST += djot_js_symb # uses ast
-BLACKLIST += sourcepos # not parsable
+BLACKLIST += djot_js_sourcepos # not parsable
 
 .PHONY: suite
 suite: mod.rs

tests/suite/footnotes.test

@@ -0,0 +1,58 @@
+Footnote references may appear within a footnote.
+
+```
+[^a]
+
+[^a]: a[^b][^c]
+[^b]: b
+.
+<p><a id="fnref1" href="#fn1" role="doc-noteref"><sup>1</sup></a></p>
+<section role="doc-endnotes">
+<hr>
+<ol>
+<li id="fn1">
+<p>a<a id="fnref2" href="#fn2" role="doc-noteref"><sup>2</sup></a><a id="fnref3" href="#fn3" role="doc-noteref"><sup>3</sup></a><a href="#fnref1" role="doc-backlink">↩︎︎</a></p>
+</li>
+<li id="fn2">
+<p>b<a href="#fnref2" role="doc-backlink">↩︎︎</a></p>
+</li>
+<li id="fn3">
+<p><a href="#fnref3" role="doc-backlink">↩︎︎</a></p>
+</li>
+</ol>
+</section>
+```
+
+Footnote references in unreferenced footnotes are ignored.
+
+```
+para
+
+[^a]: a[^b][^c]
+[^b]: b
+.
+<p>para</p>
+```
+
+Footnotes may appear within footnotes.
+
+```
+[^b]
+[^a]
+
+[^a]: [^b]: inner
+.
+<p><a id="fnref1" href="#fn1" role="doc-noteref"><sup>1</sup></a>
+<a id="fnref2" href="#fn2" role="doc-noteref"><sup>2</sup></a></p>
+<section role="doc-endnotes">
+<hr>
+<ol>
+<li id="fn1">
+<p>inner<a href="#fnref1" role="doc-backlink">↩︎︎</a></p>
+</li>
+<li id="fn2">
+<p><a href="#fnref2" role="doc-backlink">↩︎︎</a></p>
+</li>
+</ol>
+</section>
+```