module Sinatra::Templates

def render(engine, template, options={}, locals={})
  # merge app-level options
  options = self.class.send(engine).merge(options) if self.class.respond_to?(engine)
  # extract generic options
  layout = options.delete(:layout)
  layout = :layout if layout.nil? || layout == true
  views = options.delete(:views) || self.class.views || "./views"
  locals = options.delete(:locals) || locals || {}
  # render template
  data, options[:filename], options[:line] = lookup_template(engine, template, views)
  output = __send__("render_#{engine}", template, data, options, locals)
  # render layout
  if layout
    data, options[:filename], options[:line] = lookup_layout(engine, layout, views)
    if data
      output = __send__("render_#{engine}", layout, data, options, locals) { output }
    end
  end
  output
end