# File lib/readline.rb, line 204
  def self.completion_append_character=(char)
    if char.nil?
      RbReadline.rl_completion_append_character = ?\0
    elsif char.length==0
      RbReadline.rl_completion_append_character = ?\0
    else
      RbReadline.rl_completion_append_character = char[0].chr
    end
  end