gistfile1.txt

index.html.erb:
---------------------------------------------------------
<div>STUFF WE SHOULDNT SEE</div>
<% foo(:head, @hsh) do %>
  <script type="text/javascript" src="/js/work.js"></script>
<% end %>

someruby.rb
---------------------------------------------------------
def foo name, hsh
    yield
end

result:
--------------------------------------------------------
<div>STUFF WE SHOULDNT SEE</div>
  <script type="text/javascript" src="/js/work.js"></script>