83 lines
2.3 KiB
Rust
83 lines
2.3 KiB
Rust
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//! This is a demonstration of an mdBook preprocessor which parses markdown
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//! and removes any instances of emphasis.
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use mdbook::book::{Book, Chapter};
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use mdbook::errors::Error;
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use mdbook::preprocess::{CmdPreprocessor, Preprocessor, PreprocessorContext};
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use mdbook::BookItem;
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use pulldown_cmark::{Event, Parser, Tag, TagEnd};
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use std::io;
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fn main() {
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let mut args = std::env::args().skip(1);
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match args.next().as_deref() {
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Some("supports") => {
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// Supports all renderers.
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return;
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}
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Some(arg) => {
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eprintln!("unknown argument: {arg}");
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std::process::exit(1);
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}
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None => {}
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}
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if let Err(e) = handle_preprocessing() {
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eprintln!("{}", e);
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std::process::exit(1);
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}
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}
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struct RemoveEmphasis;
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impl Preprocessor for RemoveEmphasis {
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fn name(&self) -> &str {
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"remove-emphasis"
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}
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fn run(&self, _ctx: &PreprocessorContext, mut book: Book) -> Result<Book, Error> {
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let mut total = 0;
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book.for_each_mut(|item| {
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let BookItem::Chapter(ch) = item else {
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return;
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};
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if ch.is_draft_chapter() {
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return;
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}
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match remove_emphasis(&mut total, ch) {
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Ok(s) => ch.content = s,
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Err(e) => eprintln!("failed to process chapter: {e:?}"),
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}
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});
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eprintln!("removed {total} emphasis");
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Ok(book)
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}
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}
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// ANCHOR: remove_emphasis
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fn remove_emphasis(num_removed_items: &mut usize, chapter: &mut Chapter) -> Result<String, Error> {
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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| match e {
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Event::Start(Tag::Emphasis) | Event::Start(Tag::Strong) => {
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*num_removed_items += 1;
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false
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}
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Event::End(TagEnd::Emphasis) | Event::End(TagEnd::Strong) => false,
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_ => true,
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});
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Ok(pulldown_cmark_to_cmark::cmark(events, &mut buf).map(|_| buf)?)
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}
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// ANCHOR_END: remove_emphasis
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pub fn handle_preprocessing() -> Result<(), Error> {
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let pre = RemoveEmphasis;
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let (ctx, book) = CmdPreprocessor::parse_input(io::stdin())?;
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let processed_book = pre.run(&ctx, book)?;
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serde_json::to_writer(io::stdout(), &processed_book)?;
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Ok(())
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}
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