module Mail::ContentDisposition

def _nt_attribute
  start_index = index
  if node_cache[:attribute].has_key?(index)
    cached = node_cache[:attribute][index]
    @index = cached.interval.end if cached
    return cached
  end
  s0, i0 = [], index
  loop do
    r1 = _nt_token
    if r1
      s0 << r1
    else
      break
    end
  end
  if s0.empty?
    @index = i0
    r0 = nil
  else
    r0 = instantiate_node(SyntaxNode,input, i0...index, s0)
  end
  node_cache[:attribute][start_index] = r0
  r0
end