Rust port of github's cmark-gfm.
Specify it as a requirement in Cargo.toml:
[dependencies]
comrak = "0.14"Comrak supports Rust stable.
curl https://webinstall.dev/comrak | bashcurl.exe -A "MS" https://webinstall.dev/comrak | powershell$ comrak --help
comrak 0.14.0
Ashe Connor <[email protected]>
A 100% CommonMark-compatible GitHub Flavored Markdown parser and formatter
USAGE:
comrak [FLAGS] [OPTIONS] [--] [FILE]...
FLAGS:
--escape Escape raw HTML instead of clobbering it
--gfm Enable GitHub-flavored markdown extensions strikethrough, tagfilter, table, autolink, and
tasklist. It also enables --github-pre-lang.
--github-pre-lang Use GitHub-style <pre lang> for code blocks
--hardbreaks Treat newlines as hard line breaks
-h, --help Prints help information
--smart Use smart punctuation
--unsafe Allow raw HTML and dangerous URLs
-V, --version Prints version information
OPTIONS:
-c, --config-file <PATH> Path to config file containing command-line arguments, or `none'
[default: /Users/kivikakk/.config/comrak/config]
--default-info-string <INFO> Default value for fenced code block's info strings if none is given
-e, --extension <EXTENSION>... Specify an extension name to use [possible values: strikethrough,
tagfilter, table, autolink, tasklist, superscript, footnotes,
description-lists]
-t, --to <FORMAT> Specify output format [default: html] [possible values: html,
commonmark]
--front-matter-delimiter <DELIMITER> Ignore front-matter that starts and ends with the given string
--header-ids <PREFIX> Use the Comrak header IDs extension, with the given ID prefix
--list-style <LIST_STYLE> Specify bullet character for lists (-, +, *) in CommonMark ouput
[default: dash] [possible values: dash, plus, star]
-o, --output <FILE> Write output to FILE instead of stdout
--syntax-highlighting <THEME> Syntax highlighting for codefence blocks. Choose a theme or 'none' for
disabling. [default: base16-ocean.dark]
--width <WIDTH> Specify wrap width (0 = nowrap) [default: 0]
ARGS:
<FILE>... The CommonMark file to parse; or standard input if none passed
By default, Comrak will attempt to read command-line options from a config file specified by --config-file. This
behaviour can be disabled by passing --config-file none. It is not an error if the file does not exist.And there's a Rust interface. You can use comrak::markdown_to_html directly:
use comrak::{markdown_to_html, ComrakOptions};
assert_eq!(markdown_to_html("Hello, **世界**!", &ComrakOptions::default()),
"<p>Hello, <strong>世界</strong>!</p>\n");Or you can parse the input into an AST yourself, manipulate it, and then use your desired formatter:
extern crate comrak;
use comrak::{parse_document, format_html, Arena, ComrakOptions};
use comrak::nodes::{AstNode, NodeValue};
// The returned nodes are created in the supplied Arena, and are bound by its lifetime.
let arena = Arena::new();
let root = parse_document(
&arena,
"This is my input.\n\n1. Also my input.\n2. Certainly my input.\n",
&ComrakOptions::default());
fn iter_nodes<'a, F>(node: &'a AstNode<'a>, f: &F)
where F : Fn(&'a AstNode<'a>) {
f(node);
for c in node.children() {
iter_nodes(c, f);
}
}
iter_nodes(root, &|node| {
match &mut node.data.borrow_mut().value {
&mut NodeValue::Text(ref mut text) => {
let orig = std::mem::replace(text, vec![]);
*text = String::from_utf8(orig).unwrap().replace("my", "your").as_bytes().to_vec();
}
_ => (),
}
});
let mut html = vec![];
format_html(root, &ComrakOptions::default(), &mut html).unwrap();
assert_eq!(
String::from_utf8(html).unwrap(),
"<p>This is your input.</p>\n\
<ol>\n\
<li>Also your input.</li>\n\
<li>Certainly your input.</li>\n\
</ol>\n");As with cmark and cmark-gfm,
Comrak will scrub raw HTML and potentially dangerous links. This change was introduced in Comrak 0.4.0 in support of a
safe-by-default posture.
To allow these, use the unsafe_ option (or --unsafe with the command line program). If doing so, we recommend the
use of a sanitisation library like ammonia configured specific to your needs.
Comrak supports the five extensions to CommonMark defined in the GitHub Flavored Markdown Spec:
Comrak additionally supports its own extensions, which are yet to be specced out (PRs welcome!):
- Superscript
- Header IDs
- Footnotes
- Description lists
- Front matter
By default none are enabled; they are individually enabled with each parse by setting the appropriate values in the
ComrakOptions struct.
At the moment syntax highlighting of codefence blocks is the only feature that can be enhanced with plugins.
Create an implementation of the SyntaxHighlighterAdapter trait, and then provide an instance of such adapter to
ComrakPlugins.render.codefence_syntax_highlighter. For formatting a markdown document with plugins, use the
markdown_to_html_with_plugins function, which accepts your plugin as a parameter.
See the syntax_highlighter.rs and syntect.rs examples for more details.
syntect is a syntax highlighting library for Rust. By default, comrak offers
a plugin for it. In order to utilize it, create an instance of plugins::syntect::SyntectAdapter and use it as your
ComrakPlugins option.
Comrak's design goal is to model the upstream cmark-gfm as closely as possible
in terms of code structure. The upside of this is that a change in cmark-gfm has a very predictable change in Comrak.
Likewise, any bug in cmark-gfm is likely to be reproduced in Comrak. This could be considered a pro or a con,
depending on your use case.
The downside, of course, is that the code is not what I'd call idiomatic Rust (so many RefCells), and while
contributors and I have made it as fast as possible, it simply won't be as fast as some other CommonMark parsers
depending on your use-case. Here are some other projects to consider:
- Raph Levien's
pulldown-cmark. It's very fast, uses a novel parsing algorithm, and doesn't construct an AST (but you can use it to make one if you want).cargo docuses this, as do many other projects in the ecosystem. - Ben Navetta's
rcmarkis a set of bindings tolibcmark. It hasn't been updated in a while, though there's an open pull request. - Know of another library? Please open a PR to add it!
As far as I know, Comrak is the only library to implement all of the GitHub Flavored Markdown extensions to the spec, but this tends to only be important if you want to reproduce GitHub's Markdown rendering exactly, e.g. in a GitHub client app.
Contributions are highly encouraged; where possible I practice Optimistic Merging as described by Peter Hintjens. Please keep the code of conduct in mind when interacting with this project.
Thank you to comrak's many contributors for PRs and issues opened!
Become a financial contributor and help us sustain our community. [Contribute]
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Ashe Connor <ashe kivikakk ee>
Copyright (c) 2017–2021, Ashe Connor. Licensed under the 2-Clause BSD License.
cmark itself is is copyright (c) 2014, John MacFarlane.
See COPYING for all the details.