gistfile1.rbx

# Haml blocks (and ERB blocks, for that matter) don't return their contents as a string.
# They append content directly to the template.
# Thus, you need to use #capture to get their content.
# I'm not sure why this worked with ERB; it's probably just an odd consequence of an implementation detail.

# Method

  def submit(*args, &block)
    @template.content_tag(:div, :class => "save_actions") do
      super(*args) + @template.capture(&block)
    end
  end

# Calling Haml block

    = f.submit "Sign up" do
      - if @site.beta_invites?
        or 
        = link_to "Request a beta invite", new_invite_path

### Output

or
<a href="/invites/new">Request a beta invite</a> 
<div class="save_actions"><input id="user_submit" name="commit" type="submit" value="Sign up" /></div>