Short instructions that aim to help potential contributors.

Getting Started

  • Setup the Asciidoctor-revealjs plugin in development mode

  • Modify the slim templates in templates/

  • Templates need to be compiled before being used, do so with:

    bundle exec rake build
  • Then using the following command will render slides with your template changes baked in:

    bundle exec asciidoctor-revealjs <source.adoc>

The next section will provide further help on how to use print statements or a debugger to assist development.

Inspect the template system

To understand what you have access to in templates you can inject some ruby. With the slim templating system, this is done by prepending the lines with a dash (-) and inserting a ruby statement. Two complementary approaches can be used to explore the context offered by asciidoctor through the template system:

  • logging on the command line via print-like statements

  • jump into the context through an interactive debugger

Debugging is only supported via the Ruby ecosystem. You need to recompile the templates when you make changes to them. This can be done by running:

bundle exec rake build

For example to see which attributes are available, you can print them by adding these lines in the .slim file of interest:

- puts @document.attributes.inspect
- puts @attributes.inspect
- puts @document.methods

Other generally useful ruby specific introspection:

- puts instance_variables
- puts local_variables

One might find pp to produce better output (and in some cases not):

- require 'pp'
- pp @document.attributes

Interactively debug a template

Pry is a powerful debugger for ruby that features tab-completion. It is very useful to discover a complex object hierarchy like what asciidoctor offers.

Initial Setup

bundle --path=.bundle/gems --binstubs=.bundle/.bin


In order to be dropped into the debugger at a specific point in a template simply add the following two lines in the relevant .slim template file:

- require 'pry'
- binding.pry

Recompile the templates with:

bundle exec rake build

Then run asciidoctor-revealjs from the command-line to generate your document and you’ll be dropped in the debugger:

$ bundle exec asciidoctor-revealjs examples/video.adoc
asciidoctor: WARNING: level-sections.adoc: line 29: section title out of sequence: expected level 2, got level 3

From: /home/olivier/src/asciidoc/asciidoctor-reveal.js/templates/slim/section.html.slim @ line 3 :

    1: - hide_title = (title = self.title) == '!'
    2: - require 'pry'
 => 3: - binding.pry
    4: / parent section of vertical slides set
    5: - if @level == 1 && !(subsections = sections).empty?
    6:   section
    7:     section id=(hide_title ? nil : @id) data-transition=(attr 'data-transition') data-transition-speed=(attr 'data-transition-speed') data-background=(attr 'data-background') data-background-size=(attr 'data-background-size') data-background-repeat=(attr 'data-background-repeat') data-background-transition=(attr 'data-background-transition')
    8:       - unless hide_title

[1] pry(#<Asciidoctor::Section>)>

Then using commands like the following allows you to explore interactively asciidoctor’s API and object model with syntax highlighting:

[1] pry(#<Asciidoctor::Section>)> @document

You can also query asciidoctor’s documentation:

[4] pry(#<Asciidoctor::Section>)> ? find_by

If you install the pry-byebug gem you get additional debugging capabilities. See the gem’s documentation for details.

Since 1.1.0, templates are compiled. It is easier to inject the debug triggering statements and use the templates directly instead of debugging compiled templates. You can call the slim templates directly with:

bundle exec asciidoctor-revealjs --trace -T templates/ examples/customcss.adoc

Manual Tests

In order to help troubleshoot issues and test syntax improvements, some minimalist asciidoc test files are provided. You can render the tests files and then load them in a browser and check if asciidoctor-revealjs behaves as expected.

Initial Setup

Make sure to have a working version of asciidoctor-reveals this is usually done with bundler:

bundle config --local github.https true
bundle --path=.bundle/gems --binstubs=.bundle/.bin
bundle exec rake build

Go to test/doctest folder and install reveal.js:

cd test/doctest/
git clone https://github.com/hakimel/reveal.js.git

Render tests into .html

From the project’s root directory:

bundle exec rake doctest::generate FORCE=yes

Open rendered files

Right now, doctest issue #12 means that the generated examples will not be pretty.

You can open the generated .html in test/doctest/ in a Web browser.

Asciidoctor API’s gotchas

Attribute inheritence

The attr and attr? methods inherit by default. That means if they don’t find the attribute defined on the node, they look on the document.

You only want to enable inheritance if you intend to allow an attribute of the same name to be controlled globally. That might be good for configuring transitions. For instance:

= My Slides
:transition-speed: fast

== First Slide

However, there may be attributes that you don’t want to inherit. If that’s the case, you generally use the form:

attr('name', nil, false)

The second parameter value is the default attribute value, which is nil by default.

Merge / Review policy

Any non-trivial change should be integrated in master via a pull-request. This gives the community a chance to participate and helps write better code because it encourages people to review their own patches.

Pull requests should come from personal forks in order not the clutter the upstream repository.

Wait time

Once a pull request is submitted, let it sit for 24-48 hours for small changes. If you get positive feedback you can merge before the sitting time frame. If you don’t get feedback, just merge after the sitting time frame.

Larger changes should sit longer at around a week. Positive feedback or no feedback should be handled like for small changes.

Breaking changes should sit until a prominent contributor comments on the changes. Ping @mojavelinux and @obilodeau if necessary.

Remember that this is a slower moving project since people are not designing slides everyday. Well, for most people.

Work-in-progress pull-requests

Letting know to the maintainers that you are working on a feature or a fix is useful. Early communication often times save time consuming mistakes or avoids duplicated effort. We encourage contributors to communicate with us early.

Branches on forks of this project are not very visible to maintainers as much as pull requests (PR). For this reason we used to recommend sending a PR even if it’s not ready and prepend "WIP" in front of its name to let everyone see that you are working on a specific topic. Now, instead of prepending "WIP", we recommend using GitHub "draft pull request" feature instead.

'needs review' label

You can apply that label to a pull request that is complete and ready for review.

Makes triaging easier.

Node package

Test a local asciidoctor-reveal.js version

In order to test the Node package, you first need to build the converter into Javascript and create a tarball of the project.

$ bundle exec rake build:js
$ npm pack

That last command will produce a file named asciidoctor-reveal.js-<version>.tgz in the working directory.

Then, create a test project adjacent to the clone of the asciidoctor-reveal.js repository:

$ mkdir test-project
$ cd test-project

Now, install the dependencies from the tarball:

$ npm i --save ../asciidoctor-reveal.js/asciidoctor-reveal.js-<version>.tgz
The relative portion of the last command is where you are installing the local asciidoctor-reveal.js version from.

Then proceed as documented in the README.adoc.

Binary package compatibility with Asciidoctor.js

Asciidoctor.js is source-to-source compiled into JavaScript from Ruby using Opal. The JavaScript generated requires a specific version of the Opal-runtime for it to work with Node.js. This project is source-to-source compiled into JavaScript from Ruby using Opal too. In order for Asciidoctor.js to be able to call code from this converter, the versions of Opal (both runtime and compiler) must be compatible. Right now we track the exact git revision of Opal used by Asciidoctor.js and make sure that we match. Here is how:

Versions known to work together can be found by looking at the Asciidoctor.js release notes, just replace <tag> with the asciidoctor.js release you are interested in: github.com/asciidoctor/asciidoctor.js/releases/tag/<tag>;. Then that Opal version and git revision (if required) must be specified in asciidoctor-revealjs.gemspec.

Starting with 3.0.0 we aim to retain binary compatibility between Asciidoctor.js and Asciidoctor-reveal.js. This should allow other Asciidoctor extensions to be called along with this converter. Asciidoctor.js is no longer a direct dependency but should be seen as a tool that powers this converter. We need to allow users to have flexibility in the version they choose to run. Asciidoctor.js maintainer told us that he is going to consider binary package incompatibility a major break and so we adjusted our README to tell users to install with a specific version range.

We will track and maintain the README on the major version supported and recommended:

See this issue for background details on that topic.

Asciidoctor.js versioning policy is available here.


To debug the JavaScript application, just add --node-arg=--inspect-brk to the npx command to run the application. For example:

npx --node-arg=--inspect-brk asciidoctor-revealjs -v presentation.adoc

Then open the Chrome Dev Tools and click on the Node logo in the top left corner.

RubyGem package

Test a local asciidoctor-revealjs version

Compile the converter:

$ bundle exec rake build

In a clean directory besides the asciidoctor-reveal.js repository, create the following Gemspec file:

source 'https://rubygems.org'
gem 'asciidoctor-revealjs', :path => '../asciidoctor-reveal.js'

Then run:

$ bundle --path=.bundle/gems --binstubs=.bundle/.bin

Update dependencies

Update dependencies and test the package in both languages:

bundle update
bundle exec rake build
bundle exec rake test
bundle exec rake examples:convert

npm install
npm update
bundle exec rake build:js
npm test
npm run examples

Release process

Prepare the release

  1. Make sure that the changelog is up-to-date

    You can get the list of all contributors using git (don’t forget to replace %prev-version-tag% with the previous tag name):

    $ git log %prev-version-tag%.. --format="%aN" --reverse | perl -e 'my %dedupe; while (<STDIN>) { print unless $dedupe{$_}++}' | sort
  2. Make sure that the highlight plugin code embed in lib/asciidoctor-revealjs/highlightjs.rb is up-to-date with the version of reveal.js

  3. Do we need to do anything regarding our Opal dependency and Asciidoctor.js? See our section on the topic.

  4. Run the following command to prepare the release (don’t forget to replace %version% with an actual version):

    $ npm run release:prepare %version%
  5. Push your changes (including the tag):

    $ git push origin master --tags


The release process is automated and relies on GitHub Actions. We are using personal tokens to publish to rubygems.org and npmjs.com.

The RUBYGEMS_API_KEY and NPM_TOKEN secrets are configured on GitHub. See the .github/workflows/release.yml file for details.

Once the release workflow has been completed:

Prepare next version

  1. Run the following command and follow the instructions:

    $ npm run release:next

Ruby and asciidoctor-doctest tests

Running tests

We recommend tests to be run with a fresh install of all dependencies in a local folder that won’t affect your ruby install (a .bundle/ in this directory):

bundle --path=.bundle/gems --binstubs=.bundle/.bin

Then you can execute the tests with:

bundle exec rake doctest

However, if you have all dependencies properly installed this command should run the tests successfully:

rake doctest

Generating HTML test target

Tests were bootstrapped by generating them from asciidoctor-doctest’s test corpus and current asciidoctor-revealjs' slim template engine. This is done using the following command:

bundle exec rake doctest:generate FORCE=y

Custom tests

Files in the examples/ directory are used as tests. Resulting slides are kept in test/doctest/.

Netlify Integration

On every commit or PR, the Netlify service will convert some examples into slides and host the resulting pages on its platform where it will be visible by anyone. It hosts the converted HTML files, reveal.js framework and static content like images and CSS. This integration will allow us to easily preview PRs and demo features to users (source and converted result). See the publish rake task in Rakefile and the netlify.toml configuration file.

Sensitive Data Accidentally Pushed Out

Only content that is copied into the public/ directory will be published on the Netlify site. If, by accident, something sensitive is copied over there, delete it, rewrite the git history to remove the sensitive information and force push the branch. Reach out to our netlify integration contact to make sure that deployed branches were rebuilt and no longer contain the sensitive information.

Integration Contact

Main Contact: @Mogztter

Also, in order to stay with a free plan, only the following people have control over our netlify integration: @Mogztter, @mojavelinux and @graphitefriction.