Sinatra render a ruby file

How to render a ruby file (which in my case returns a pdf document) for example:

 get "/pdf" do
  @locals = {some_locals_hash}
  headers({'Content-Type' => 'application/pdf',
    'Content-Description' => 'File Transfer',
    'Content-Transfer-Encoding' => 'binary',
    'Content-Disposition' => "attachment;filename=\"test.pdf\"",
    'Expires' => '0',
    'Pragma' => 'public'})
  ruby :test, :layout => false, :locals => @locals
 end

I know Tilt does not have ruby template. For now I put all content in a *.haml file like:

 -# PDF file description
 :ruby
   pdf = Prawn::Do开发者_如何学运维cument.new(
     ... docs settings)
     ... docs content
   end
 = pdf.render()

and I render it with haml :template ...etc...

Truth is, I only need this for syntax highlighting, my editor does not properly highlight embedded ruby code in haml files :(. So if it's to complicated don't bother...

I managed with a Tilt template

module Tilt
  class RubyTemplate < Template
    def prepare
    end

    def evaluate(scope, locals, &block)
      super(scope, locals, &block)
    end

    def precompiled_template(locals)
      data.to_str
    end
  end
  register 'rb', RubyTemplate
end

and with a helper method

helpers do
  def ruby(*args) 
    render(:rb, *args) 
  end
end

I't sure this is the best way, but at least is working :)