f51d89ba02
This moves Result and Error to mdbook-core with the anticipation of using them in user crates. For now, the internal APIs will be using anyhow directly, but the intent is to transition more of these to mdbook-core where it makes sense.
82 lines
2.3 KiB
Rust
82 lines
2.3 KiB
Rust
//! 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 anyhow::Error;
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use mdbook::BookItem;
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use mdbook::book::{Book, Chapter};
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use mdbook::preprocess::{CmdPreprocessor, Preprocessor, PreprocessorContext};
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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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