[Ruby] ERB block question

[James Hillyerd]

Hello,

I've got a non-Rails project in which I'm using ERB.   I'd really like to
duplicate Rails' "content_for" block/yield setup.  It wasn't hard to find
the code that Rails uses for the content_for helper, but when I use it
thusly:

(child template)
<% content_for :head do %>
    <script>alert('test')</script>
<% end %>

(parent template)
<%= yield :head %>

I get an error when executing the parent template: (line nine is the one
that contains the yield statement)

(erb):9:in `get_binding': no block given (LocalJumpError)

Obviously, I need to write a block that accepts the :head argument and
returns the result stored in @content_for_head.  What I can figure our is
where to pass that block into ERB.  The ERB.new class method does not accept
a block (that I can see), neither does the ERB.result instance method.  My
guess would be it's part of the context/binding I pass to ERB, but I've
tried grepping the rails codebase and cannot find the place it sets this up.

Can anyone help?

Thanks.

-james

-- 
James A. Hillyerd <james at hillyerd.com>
Chief Technical Officer - ActiveRain Corp