mdBook/examples/de-emphasize.rs

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//! This program removes all forms of emphasis from the markdown of the book.
extern crate mdbook;
extern crate pulldown_cmark;
extern crate pulldown_cmark_to_cmark;
use mdbook::errors::{Error, Result};
use mdbook::MDBook;
use mdbook::book::{Book, BookItem, Chapter};
use mdbook::preprocess::{Preprocessor, PreprocessorContext};
use pulldown_cmark::{Event, Parser, Tag};
use pulldown_cmark_to_cmark::fmt::cmark;
use std::ffi::OsString;
use std::env::{args, args_os};
use std::process;
struct Deemphasize;
impl Preprocessor for Deemphasize {
fn name(&self) -> &str {
"md-links-to-html-links"
}
fn run(&self, _ctx: &PreprocessorContext, book: &mut Book) -> Result<()> {
eprintln!("Running '{}' preprocessor", self.name());
let mut res: Option<_> = None;
let mut num_removed_items = 0;
book.for_each_mut(|item: &mut BookItem| {
if let Some(Err(_)) = res {
return;
}
if let BookItem::Chapter(ref mut chapter) = *item {
eprintln!("{}: processing chapter '{}'", self.name(), chapter.name);
res = Some(
match Deemphasize::remove_emphasis(&mut num_removed_items, chapter) {
Ok(md) => {
chapter.content = md;
Ok(())
}
Err(err) => Err(err),
},
);
}
});
eprintln!(
"{}: removed {} events from markdown stream.",
self.name(),
num_removed_items
);
match res {
Some(res) => res,
None => Ok(()),
}
}
}
fn do_it(book: OsString) -> Result<()> {
let mut book = MDBook::load(book)?;
book.with_preprecessor(Deemphasize);
book.build()
}
fn main() {
if args_os().count() != 2 {
eprintln!("USAGE: {} <book>", args().next().expect("executable"));
return;
}
if let Err(e) = do_it(args_os().skip(1).next().expect("one argument")) {
eprintln!("{}", e);
process::exit(1);
}
}
impl Deemphasize {
fn remove_emphasis(num_removed_items: &mut i32, chapter: &mut Chapter) -> Result<String> {
let mut buf = String::with_capacity(chapter.content.len());
let events = Parser::new(&chapter.content).filter(|e| {
let should_keep = match *e {
Event::Start(Tag::Emphasis)
| Event::Start(Tag::Strong)
| Event::End(Tag::Emphasis)
| Event::End(Tag::Strong) => false,
_ => true,
};
if !should_keep {
*num_removed_items += 1;
}
should_keep
});
cmark(events, &mut buf, None)
.map(|_| buf)
.map_err(|err| Error::from(format!("Markdown serialization failed: {}", err)))
}
}