module Sinatra::Templates

def render(engine, data, options = {}, locals = {}, &block)
  # merge app-level options
  engine_options = settings.respond_to?(engine) ? settings.send(engine) : {}
  options.merge!(engine_options) { |key, v1, v2| v1 }
  # extract generic options
  locals          = options.delete(:locals) || locals         || {}
  views           = options.delete(:views)  || settings.views || "./views"
  layout          = options[:layout]
  layout          = false if layout.nil? && options.include?(:layout)
  eat_errors      = layout.nil?
  layout          = engine_options[:layout] if layout.nil? or (layout == true && engine_options[:layout] != false)
  layout          = @default_layout         if layout.nil? or layout == true
  layout_options  = options.delete(:layout_options) || {}
  content_type    = options.delete(:default_content_type)
  content_type    = options.delete(:content_type)   || content_type
  layout_engine   = options.delete(:layout_engine)  || engine
  scope           = options.delete(:scope)          || self
  options.delete(:layout)
  # set some defaults
  options[:outvar]           ||= '@_out_buf'
  options[:default_encoding] ||= settings.default_encoding
  # compile and render template
  begin
    layout_was      = @default_layout
    @default_layout = false
    template        = compile_template(engine, data, options, views)
    output          = template.render(scope, locals, &block)
  ensure
    @default_layout = layout_was
  end
  # render layout
  if layout
    options = options.merge(:views => views, :layout => false, :eat_errors => eat_errors, :scope => scope).
            merge!(layout_options)
    catch(:layout_missing) { return render(layout_engine, layout, options, locals) { output } }
  end
  output.extend(ContentTyped).content_type = content_type if content_type
  output
end