class IRB::Irb

def prompt(prompt, ltype, indent, line_no) # :nodoc:
  p = prompt.dup
  p.gsub!(/%([0-9]+)?([a-zA-Z])/) do
    case $2
    when "N"
      @context.irb_name
    when "m"
      truncate_prompt_main(@context.main.to_s)
    when "M"
      truncate_prompt_main(@context.main.inspect)
    when "l"
      ltype
    when "i"
      if indent < 0
        if $1
          "-".rjust($1.to_i)
        else
          "-"
        end
      else
        if $1
          format("%" + $1 + "d", indent)
        else
          indent.to_s
        end
      end
    when "n"
      if $1
        format("%" + $1 + "d", line_no)
      else
        line_no.to_s
      end
    when "%"
      "%"
    end
  end
  p
end