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