# File rbot/ircbot.rb, line 424
  def help(topic=nil)
    topic = nil if topic == ""
    case topic
    when nil
      helpstr = "help topics: core, auth, keywords"
      helpstr += @plugins.helptopics
      helpstr += " (help <topic> for more info)"
    when /^core$/
      helpstr = corehelp
    when /^core\s+(.+)$/
      helpstr = corehelp $1
    when /^auth$/
      helpstr = @auth.help
    when /^auth\s+(.+)$/
      helpstr = @auth.help $1
    when /^keywords$/
      helpstr = @keywords.help
    when /^keywords\s+(.+)$/
      helpstr = @keywords.help $1
    else
      unless(helpstr = @plugins.help(topic))
        helpstr = "no help for topic #{topic}"
      end
    end
    return helpstr
  end