76 lines
2.1 KiB
Rust
76 lines
2.1 KiB
Rust
//! An example preprocessor for removing all forms of emphasis from a markdown
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//! book.
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use mdbook::book::{Book, BookItem, Chapter};
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use mdbook::errors::{Error, Result};
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use mdbook::preprocess::{Preprocessor, PreprocessorContext};
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use pulldown_cmark::{Event, Parser, Tag};
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use pulldown_cmark_to_cmark::fmt::cmark;
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const NAME: &str = "md-links-to-html-links";
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fn main() {
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panic!("This example is intended to be part of a library");
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}
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#[allow(dead_code)]
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struct Deemphasize;
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impl Preprocessor for Deemphasize {
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fn name(&self) -> &str {
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NAME
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}
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fn run(&self, _ctx: &PreprocessorContext, mut book: Book) -> Result<Book> {
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eprintln!("Running '{}' preprocessor", self.name());
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let mut num_removed_items = 0;
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process(&mut book.sections, &mut num_removed_items)?;
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eprintln!(
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"{}: removed {} events from markdown stream.",
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self.name(),
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num_removed_items
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);
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Ok(book)
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}
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}
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fn process<'a, I>(items: I, num_removed_items: &mut usize) -> Result<()>
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where
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I: IntoIterator<Item = &'a mut BookItem> + 'a,
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{
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for item in items {
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if let BookItem::Chapter(ref mut chapter) = *item {
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eprintln!("{}: processing chapter '{}'", NAME, chapter.name);
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let md = remove_emphasis(num_removed_items, chapter)?;
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chapter.content = md;
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}
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}
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Ok(())
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}
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fn remove_emphasis(num_removed_items: &mut usize, chapter: &mut Chapter) -> Result<String> {
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let mut buf = String::with_capacity(chapter.content.len());
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let events = Parser::new(&chapter.content).filter(|e| {
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let should_keep = match *e {
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Event::Start(Tag::Emphasis)
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| Event::Start(Tag::Strong)
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| Event::End(Tag::Emphasis)
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| Event::End(Tag::Strong) => false,
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_ => true,
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};
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if !should_keep {
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*num_removed_items += 1;
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}
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should_keep
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});
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cmark(events, &mut buf, None)
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.map(|_| buf)
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.map_err(|err| Error::from(format!("Markdown serialization failed: {}", err)))
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}
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