BRB

BRB is backslashed Ruby, a template system that lets you be-right-back to ERB.

BRB aims to be a simpler syntax, but still a superset of ERB, that's aware of the context we're in: HTML.

We're swapping the usual <% %>, <%= %>, and <%# %> for \, = and # — these are also self-terminating expressions.

So this ERB:

<%# Some comment %>
<% posts.each do |post| %>
  <h1><%= post.title %></h1>
<% end %>

Can be this in BRB:

\# Some comment
\posts.each do |post|
  <h1>\= post.title</h1>
\end

Note: you can also do \ posts.each and \ end, it just feels a little nicer to nestle once you've written a bit.

We recognize lines starting with \ or # as pure Ruby ones so we terminate on \n and convert to <% %>. Same goes for = except we also terminate on </, and then convert to <%= %>.

Use the sigil \p(post.title) for multiple statements on the same line or to otherwise disambiguate statements.

Preprocessing sigils

BRB also includes preprocessing sigils. Sigils make common HTML output actions easier to write.

At template compile time the sigils are replaced with the equivalent ERB:

\p(post.options) -> <%= post.options %>
\id(post) -> id="<%= dom_id(post) %>"
\class(active: post.active?) -> class="<%= class_names(active: post.active?) %>"
\attributes(post.options) -> <%= tag.attributes(post.options) %>
\data(controller: :list) -> <%= tag.data(controller: :list) %>
\aria(describedby: :post_1) -> <%= tag.aria(describedby: :post_1) %>
\lorem -> Lorem ipsum dolor sit amet…

There's also a t sigil, but it's got a little extra too:

\t.message -> <%= t ".message" %>
\t(fully.qualified.message) -> <%= t "fully.qualified.message" %>
\t(Some bare words) -> <%= t "Some bare words" %> # Assumes we're using a gettext I18n backend, coming later!

Embed ViewComponents with their templates

I haven't figured this out, but I'm trying to explore a way to embed a component in its template. Using ~~~ to separate the frontmatter, a pure Ruby chunk where the component code goes, from the rest of the template file like this:

# app/views/message_component.html.erb
class MessageComponent < ViewComponent::Base
  def initialize(name:) = @name = name
end
~~~

<h1>\= @name</h1>

I'm exploring a backmatter version where you can write pure Ruby below the template code:

<h1>\= name</h1>

~~~
# Useful with Nice Partials
partial.helpers do
  # …
end

I'm still trying to figure out what Zeitwerk overrides are needed to make these work.

Installation

Bundle BRB and call BRB.enable during your Rails app boot to use it.

Install the gem and add to the application's Gemfile by executing:

$ bundle add brb-templates

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install brb-templates

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/kaspth/brb. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Brb project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.