example.json.rb

{
  :a => 2,
  # NOTE for partials, you need to include the format
  # otherwise, it'll fail to find byows/_byow.erb even if byows/_byow.html.erb exists
  :b => render(:partial => 'example.html')
}.to_json

rbtemplate.rb

class RbTemplate < ActionView::TemplateHandler
  include ActionView::TemplateHandlers::Compilable if defined?(ActionView::TemplateHandlers::Compilable)


  def compile(template)
    template.source
  end

end

ActionView::Template.register_template_handler(:rb, RbTemplate)