def space_before?
      position = begin_pos.zero? ? begin_pos : begin_pos - 1
      pos.source_buffer.source.match(/\G\s/, position)
    end
def space_before?
      position = begin_pos.zero? ? begin_pos : begin_pos - 1
      pos.source_buffer.source.match(/\G\s/, position)
    end
Checks if there is whitespace before token