module Temple::Mixins::EngineDSL

def chain_class_constructor(filter, local_options)
  define_options(filter.options.valid_keys) if respond_to?(:define_options) && filter.respond_to?(:options)
  proc do |engine|
    opts = {}.update(engine.options)
    opts.delete_if {|k,v| !filter.options.valid_key?(k) } if filter.respond_to?(:options)
    opts.update(local_options) if local_options
    filter.new(opts)
  end
end