def run(content, params={})
options = params.dup
sass_filename = options[:filename] ||
(@item && @item[:content_filename])
options[:filename] ||= sass_filename
options[:filesystem_importer] ||=
Nanoc::Filters::Sass::SassFilesystemImporter
item_dirglob = Pathname.new(sass_filename).dirname.realpath.to_s + '**'
clean_items = @items.reject { |i| i[:content_filename].nil? }
@scoped_items, @rest_items = clean_items.partition do |i|
i[:content_filename] &&
Pathname.new(i[:content_filename]).realpath.fnmatch(item_dirglob)
end
engine = ::Sass::Engine.new(content, options)
self.class.current = self
engine.render
end