class Asciidoctor::Document

def docinfo_processors?(location = :head)
  if @docinfo_processor_extensions.key?(location)
    # false means we already performed a lookup and didn't find any
    @docinfo_processor_extensions[location] != false
  elsif @extensions && @document.extensions.docinfo_processors?(location)
    !!(@docinfo_processor_extensions[location] = @document.extensions.docinfo_processors(location))
  else
    @docinfo_processor_extensions[location] = false
  end
end