a603ea2124
keep the tag for unresolved links, and allow distinguishing between `[tag][tag with empty url]` and `[tag][non-existent tag]`. closes #26
478 lines
22 KiB
Rust
478 lines
22 KiB
Rust
//! An HTML renderer that takes an iterator of [`Event`]s and emits HTML.
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//!
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//! The HTML can be written to either a [`std::fmt::Write`] or a [`std::io::Write`] object.
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//!
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//! # Examples
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//!
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//! Push to a [`String`] (implements [`std::fmt::Write`]):
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//!
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//! ```
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//! # use jotdown::Render;
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//! # let events = std::iter::empty();
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//! let mut html = String::new();
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//! jotdown::html::Renderer.push(events, &mut html);
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//! ```
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//!
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//! Write to standard output with buffering ([`std::io::Stdout`] implements [`std::io::Write`]):
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//!
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//! ```
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//! # use jotdown::Render;
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//! # let events = std::iter::empty();
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//! let mut out = std::io::BufWriter::new(std::io::stdout());
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//! jotdown::html::Renderer.write(events, &mut out).unwrap();
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//! ```
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use crate::Alignment;
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use crate::Container;
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use crate::Event;
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use crate::LinkType;
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use crate::ListKind;
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use crate::OrderedListNumbering::*;
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use crate::Render;
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use crate::SpanLinkType;
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pub struct Renderer;
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impl Render for Renderer {
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fn push<'s, I: Iterator<Item = Event<'s>>, W: std::fmt::Write>(
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&self,
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events: I,
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out: W,
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) -> std::fmt::Result {
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Writer::new(events, out).write()
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}
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}
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enum Raw {
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None,
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Html,
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Other,
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}
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struct FilteredEvents<I> {
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events: I,
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}
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impl<'s, I: Iterator<Item = Event<'s>>> Iterator for FilteredEvents<I> {
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type Item = Event<'s>;
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fn next(&mut self) -> Option<Self::Item> {
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let mut ev = self.events.next();
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while matches!(ev, Some(Event::Blankline | Event::Escape)) {
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ev = self.events.next();
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}
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ev
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}
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}
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struct Writer<'s, I: Iterator<Item = Event<'s>>, W> {
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events: std::iter::Peekable<FilteredEvents<I>>,
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out: W,
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raw: Raw,
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img_alt_text: usize,
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list_tightness: Vec<bool>,
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encountered_footnote: bool,
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footnote_number: Option<std::num::NonZeroUsize>,
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footnote_backlink_written: bool,
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first_line: bool,
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}
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impl<'s, I: Iterator<Item = Event<'s>>, W: std::fmt::Write> Writer<'s, I, W> {
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fn new(events: I, out: W) -> Self {
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Self {
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events: FilteredEvents { events }.peekable(),
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out,
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raw: Raw::None,
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img_alt_text: 0,
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list_tightness: Vec::new(),
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encountered_footnote: false,
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footnote_number: None,
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footnote_backlink_written: false,
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first_line: true,
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}
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}
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fn write(&mut self) -> std::fmt::Result {
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while let Some(e) = self.events.next() {
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match e {
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Event::Start(c, attrs) => {
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if c.is_block() && !self.first_line {
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self.out.write_char('\n')?;
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}
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if self.img_alt_text > 0 && !matches!(c, Container::Image(..)) {
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continue;
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}
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match &c {
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Container::Blockquote => self.out.write_str("<blockquote")?,
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Container::List { kind, tight } => {
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self.list_tightness.push(*tight);
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match kind {
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ListKind::Unordered | ListKind::Task => {
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self.out.write_str("<ul")?
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}
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ListKind::Ordered {
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numbering, start, ..
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} => {
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self.out.write_str("<ol")?;
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if *start > 1 {
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write!(self.out, r#" start="{}""#, start)?;
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}
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if let Some(ty) = match numbering {
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Decimal => None,
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AlphaLower => Some('a'),
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AlphaUpper => Some('A'),
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RomanLower => Some('i'),
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RomanUpper => Some('I'),
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} {
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write!(self.out, r#" type="{}""#, ty)?;
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}
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}
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}
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}
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Container::ListItem | Container::TaskListItem { .. } => {
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self.out.write_str("<li")?;
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}
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Container::DescriptionList => self.out.write_str("<dl")?,
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Container::DescriptionDetails => self.out.write_str("<dd")?,
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Container::Footnote { number, .. } => {
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assert!(self.footnote_number.is_none());
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self.footnote_number = Some((*number).try_into().unwrap());
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if !self.encountered_footnote {
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self.encountered_footnote = true;
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self.out
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.write_str("<section role=\"doc-endnotes\">\n<hr>\n<ol>\n")?;
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}
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write!(self.out, "<li id=\"fn{}\">", number)?;
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self.footnote_backlink_written = false;
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continue;
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}
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Container::Table => self.out.write_str("<table")?,
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Container::TableRow { .. } => self.out.write_str("<tr")?,
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Container::Section { .. } => self.out.write_str("<section")?,
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Container::Div { .. } => self.out.write_str("<div")?,
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Container::Paragraph => {
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if matches!(self.list_tightness.last(), Some(true)) {
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continue;
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}
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self.out.write_str("<p")?;
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}
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Container::Heading { level, .. } => write!(self.out, "<h{}", level)?,
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Container::TableCell { head: false, .. } => self.out.write_str("<td")?,
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Container::TableCell { head: true, .. } => self.out.write_str("<th")?,
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Container::Caption => self.out.write_str("<caption")?,
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Container::DescriptionTerm => self.out.write_str("<dt")?,
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Container::CodeBlock { .. } => self.out.write_str("<pre")?,
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Container::Span | Container::Math { .. } => self.out.write_str("<span")?,
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Container::Link(dst, ty) => {
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if matches!(ty, LinkType::Span(SpanLinkType::Unresolved)) {
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self.out.write_str("<a")?;
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} else {
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self.out.write_str(r#"<a href=""#)?;
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if matches!(ty, LinkType::Email) {
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self.out.write_str("mailto:")?;
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}
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self.write_attr(dst)?;
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self.out.write_char('"')?;
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}
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}
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Container::Image(..) => {
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self.img_alt_text += 1;
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if self.img_alt_text == 1 {
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self.out.write_str("<img")?;
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} else {
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continue;
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}
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}
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Container::Verbatim => self.out.write_str("<code")?,
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Container::RawBlock { format } | Container::RawInline { format } => {
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self.raw = if format == &"html" {
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Raw::Html
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} else {
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Raw::Other
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};
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continue;
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}
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Container::Subscript => self.out.write_str("<sub")?,
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Container::Superscript => self.out.write_str("<sup")?,
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Container::Insert => self.out.write_str("<ins")?,
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Container::Delete => self.out.write_str("<del")?,
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Container::Strong => self.out.write_str("<strong")?,
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Container::Emphasis => self.out.write_str("<em")?,
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Container::Mark => self.out.write_str("<mark")?,
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}
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for (a, v) in attrs.iter().filter(|(a, _)| *a != "class") {
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write!(self.out, r#" {}=""#, a)?;
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v.parts().try_for_each(|part| self.write_attr(part))?;
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self.out.write_char('"')?;
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}
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if let Container::Heading {
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id,
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has_section: false,
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..
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}
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| Container::Section { id } = &c
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{
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if !attrs.iter().any(|(a, _)| a == "id") {
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self.out.write_str(r#" id=""#)?;
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self.write_attr(id)?;
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self.out.write_char('"')?;
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}
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}
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if attrs.iter().any(|(a, _)| a == "class")
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|| matches!(
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c,
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Container::Div { class: Some(_) }
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| Container::Math { .. }
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| Container::List {
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kind: ListKind::Task,
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..
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}
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| Container::TaskListItem { .. }
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)
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{
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self.out.write_str(r#" class=""#)?;
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let mut first_written = false;
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if let Some(cls) = match c {
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Container::List {
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kind: ListKind::Task,
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..
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} => Some("task-list"),
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Container::TaskListItem { checked: false } => Some("unchecked"),
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Container::TaskListItem { checked: true } => Some("checked"),
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Container::Math { display: false } => Some("math inline"),
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Container::Math { display: true } => Some("math display"),
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_ => None,
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} {
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first_written = true;
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self.out.write_str(cls)?;
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}
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for cls in attrs
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.iter()
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.filter(|(a, _)| a == &"class")
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.map(|(_, cls)| cls)
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{
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if first_written {
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self.out.write_char(' ')?;
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}
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first_written = true;
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cls.parts().try_for_each(|part| self.write_attr(part))?;
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}
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// div class goes after classes from attrs
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if let Container::Div { class: Some(cls) } = c {
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if first_written {
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self.out.write_char(' ')?;
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}
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self.out.write_str(cls)?;
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}
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self.out.write_char('"')?;
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}
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match c {
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Container::TableCell { alignment, .. }
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if !matches!(alignment, Alignment::Unspecified) =>
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{
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let a = match alignment {
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Alignment::Unspecified => unreachable!(),
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Alignment::Left => "left",
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Alignment::Center => "center",
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Alignment::Right => "right",
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};
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write!(self.out, r#" style="text-align: {};">"#, a)?;
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}
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Container::CodeBlock { lang } => {
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if let Some(l) = lang {
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self.out.write_str(r#"><code class="language-"#)?;
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self.write_attr(l)?;
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self.out.write_str(r#"">"#)?;
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} else {
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self.out.write_str("><code>")?;
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}
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}
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Container::Image(..) => {
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if self.img_alt_text == 1 {
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self.out.write_str(r#" alt=""#)?;
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}
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}
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Container::Math { display } => {
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self.out
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.write_str(if display { r#">\["# } else { r#">\("# })?;
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}
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_ => self.out.write_char('>')?,
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}
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}
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Event::End(c) => {
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if c.is_block_container() && !matches!(c, Container::Footnote { .. }) {
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self.out.write_char('\n')?;
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}
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if self.img_alt_text > 0 && !matches!(c, Container::Image(..)) {
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continue;
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}
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match c {
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Container::Blockquote => self.out.write_str("</blockquote>")?,
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Container::List {
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kind: ListKind::Unordered | ListKind::Task,
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..
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} => {
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self.list_tightness.pop();
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self.out.write_str("</ul>")?;
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}
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Container::List {
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kind: ListKind::Ordered { .. },
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..
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} => self.out.write_str("</ol>")?,
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Container::ListItem | Container::TaskListItem { .. } => {
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self.out.write_str("</li>")?;
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}
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Container::DescriptionList => self.out.write_str("</dl>")?,
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Container::DescriptionDetails => self.out.write_str("</dd>")?,
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Container::Footnote { number, .. } => {
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if !self.footnote_backlink_written {
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write!(
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self.out,
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"\n<p><a href=\"#fnref{}\" role=\"doc-backlink\">↩︎︎</a></p>",
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number,
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)?;
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}
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self.out.write_str("\n</li>")?;
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self.footnote_number = None;
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}
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Container::Table => self.out.write_str("</table>")?,
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Container::TableRow { .. } => self.out.write_str("</tr>")?,
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Container::Section { .. } => self.out.write_str("</section>")?,
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Container::Div { .. } => self.out.write_str("</div>")?,
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Container::Paragraph => {
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if matches!(self.list_tightness.last(), Some(true)) {
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continue;
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}
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if let Some(num) = self.footnote_number {
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if matches!(
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self.events.peek(),
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Some(Event::End(Container::Footnote { .. }))
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) {
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write!(
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self.out,
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r##"<a href="#fnref{}" role="doc-backlink">↩︎︎</a>"##,
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num
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)?;
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self.footnote_backlink_written = true;
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}
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}
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self.out.write_str("</p>")?;
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}
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Container::Heading { level, .. } => write!(self.out, "</h{}>", level)?,
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Container::TableCell { head: false, .. } => self.out.write_str("</td>")?,
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Container::TableCell { head: true, .. } => self.out.write_str("</th>")?,
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Container::Caption => self.out.write_str("</caption>")?,
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Container::DescriptionTerm => self.out.write_str("</dt>")?,
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Container::CodeBlock { .. } => self.out.write_str("</code></pre>")?,
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Container::Span => self.out.write_str("</span>")?,
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Container::Link(..) => self.out.write_str("</a>")?,
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Container::Image(src, ..) => {
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if self.img_alt_text == 1 {
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if !src.is_empty() {
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self.out.write_str(r#"" src=""#)?;
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self.write_attr(&src)?;
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}
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self.out.write_str(r#"">"#)?;
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}
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self.img_alt_text -= 1;
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}
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Container::Verbatim => self.out.write_str("</code>")?,
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Container::Math { display } => {
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self.out.write_str(if display {
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r#"\]</span>"#
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} else {
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r#"\)</span>"#
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})?;
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}
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Container::RawBlock { .. } | Container::RawInline { .. } => {
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self.raw = Raw::None;
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}
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Container::Subscript => self.out.write_str("</sub>")?,
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Container::Superscript => self.out.write_str("</sup>")?,
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Container::Insert => self.out.write_str("</ins>")?,
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Container::Delete => self.out.write_str("</del>")?,
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Container::Strong => self.out.write_str("</strong>")?,
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Container::Emphasis => self.out.write_str("</em>")?,
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Container::Mark => self.out.write_str("</mark>")?,
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}
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}
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Event::Str(s) => match self.raw {
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Raw::None if self.img_alt_text > 0 => self.write_attr(&s)?,
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Raw::None => self.write_text(&s)?,
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Raw::Html => self.out.write_str(&s)?,
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Raw::Other => {}
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},
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Event::FootnoteReference(_tag, number) => {
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if self.img_alt_text == 0 {
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write!(
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self.out,
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r##"<a id="fnref{}" href="#fn{}" role="doc-noteref"><sup>{}</sup></a>"##,
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number, number, number
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)?;
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}
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}
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Event::Symbol(sym) => write!(self.out, ":{}:", sym)?,
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Event::LeftSingleQuote => self.out.write_str("‘")?,
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Event::RightSingleQuote => self.out.write_str("’")?,
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Event::LeftDoubleQuote => self.out.write_str("“")?,
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Event::RightDoubleQuote => self.out.write_str("”")?,
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Event::Ellipsis => self.out.write_str("…")?,
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Event::EnDash => self.out.write_str("–")?,
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Event::EmDash => self.out.write_str("—")?,
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Event::NonBreakingSpace => self.out.write_str(" ")?,
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Event::Hardbreak => self.out.write_str("<br>\n")?,
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Event::Softbreak => self.out.write_char('\n')?,
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Event::Escape | Event::Blankline => unreachable!("filtered out"),
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Event::ThematicBreak(attrs) => {
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self.out.write_str("\n<hr")?;
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for (a, v) in attrs.iter() {
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write!(self.out, r#" {}=""#, a)?;
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v.parts().try_for_each(|part| self.write_attr(part))?;
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self.out.write_char('"')?;
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}
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self.out.write_str(">")?;
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}
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}
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self.first_line = false;
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}
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if self.encountered_footnote {
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self.out.write_str("\n</ol>\n</section>")?;
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}
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self.out.write_char('\n')?;
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Ok(())
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}
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fn write_escape(&mut self, mut s: &str, escape_quotes: bool) -> std::fmt::Result {
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let mut ent = "";
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while let Some(i) = s.find(|c| {
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match c {
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'<' => Some("<"),
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'>' => Some(">"),
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'&' => Some("&"),
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'"' if escape_quotes => Some("""),
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_ => None,
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}
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.map_or(false, |s| {
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ent = s;
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true
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})
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}) {
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self.out.write_str(&s[..i])?;
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self.out.write_str(ent)?;
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s = &s[i + 1..];
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}
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self.out.write_str(s)
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}
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fn write_text(&mut self, s: &str) -> std::fmt::Result {
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self.write_escape(s, false)
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}
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fn write_attr(&mut self, s: &str) -> std::fmt::Result {
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self.write_escape(s, true)
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}
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}
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