Apex Ruby Bindings

Ruby bindings for the Apex unified Markdown processor.

Apex is a C library that supports CommonMark, GFM, MultiMarkdown, Kramdown, and a number of Marked-specific extensions. This gem vendors the Apex sources and exposes a small, kramdown-style Ruby API for converting Markdown to HTML.

Before installing the gem, you must have the cmark-gfm C library available on your system. The gem compiles a native extension that links against it.

• macOS (Homebrew):

  brew install cmark-gfm

• Other platforms: Install the cmark-gfm package for your distribution and ensure development headers and pkg-config are available. See cmark-gfm for build instructions.

If you run gem install apex-ruby without cmark-gfm installed, the build will fail with a clear error message and the same installation instructions.

Add this line to your application's Gemfile:

gem "apex-ruby"

And then execute:

bundle install

Or install it yourself as:

gem install apex-ruby

The main API mirrors the simplicity of the kramdown gem:

require "apex"

html = Apex::Document.markdown_to_html(text)

You can select a compatibility mode via the mode: keyword argument:

html = Apex::Document.markdown_to_html(text, mode: :unified)      # default
html = Apex::Document.markdown_to_html(text, mode: :gfm)          # or :github
html = Apex::Document.markdown_to_html(text, mode: :multimarkdown) # or :mmd
html = Apex::Document.markdown_to_html(text, mode: :commonmark)   # or :cmark
html = Apex::Document.markdown_to_html(text, mode: :kramdown)

Any additional keyword arguments are mapped directly to the underlying apex_options struct defined in apex.h. For example:

html = Apex::Document.markdown_to_html(
  text,
  mode: :unified,
  enable_tables: true,
  enable_footnotes: true,
  generate_header_ids: true,
  relaxed_tables: true,
  wikilink_extension: "html"
)

See the Apex documentation for the complete list of options and their semantics.

If you prefer an object-oriented style (similar to Kramdown::Document), you can use Apex::Document instances:

doc = Apex::Document.new(text, mode: :gfm, enable_tables: true)
html = doc.to_html

You can use Apex as Jekyll’s Markdown converter instead of Kramdown via a custom converter plugin. See Jekyll-Apex.md for step-by-step instructions. That integration is currently untested and documented as a placeholder; feedback from anyone willing to try it is welcome at ApexMarkdown/apex-ruby/issues.

To run the test suite:

bundle exec rake test

To build and install the gem into all Ruby versions managed by mise:

bundle exec rake install

This will:

1. Build pkg/apex-ruby-<version>.gem
2. Run gem install for each Ruby reported by mise ls ruby.

This project is licensed under the MIT license. See the Apex repository for the license of the underlying C implementation.