Enable preprocessing in erubis with the <%=== %> directive

erubis_preprocessing.rb

# Just drop this in the initializers directory of a rails 3 app and then use <%=== code %> in your templates
# and the code will be eval'ed at compile time, for example:  <%=== link_to 'home', '/' %> actually puts
# <a href="/">home</a> in the compiled template avoiding the need to call link_to on every render 
# This can provide a significant speedup of your rails views but beware that many rails helpers can produce 
# different output depending on the context that is not available at compile time. 
# For example, @form.text_field :name would produce different HTML if there was an error on the :name field.
# It doesn't work yet on asset tags like <%= javascript_include_tag :default %>


module ActionView
  class Base
    def get_binding
      return binding
    end
  end

  class Template
    module Handlers
      class Erubis < ::Erubis::Eruby

        def add_expr_debug(src, code)
          src << "@output_buffer.safe_concat('" << escape_text(eval(code,ActionView::Base.new.get_binding).to_s) << "');"
        end

      end
    end
  end
end