def_extend_command

# File lib/irb/extend-command.rb, line 131
    def self.def_extend_command(cmd_name, cmd_class, load_file = nil, *aliases)
      case cmd_class
      when Symbol
        cmd_class = cmd_class.id2name
      when String
      when Class
        cmd_class = cmd_class.name
      end

      if load_file
        line = __LINE__; eval %[
          def #{cmd_name}(*opts, &b)
            require "#{load_file}"
            arity = ExtendCommand::#{cmd_class}.instance_method(:execute).arity
            args = (1..(arity < 0 ? ~arity : arity)).map {|i| "arg" + i.to_s }
            args << "*opts" if arity < 0
            args << "&block"
            args = args.join(", ")
            line = __LINE__; eval %[
              def #{cmd_name}(\#{args})
            ExtendCommand::#{cmd_class}.execute(irb_context, \#{args})
              end
            ], nil, __FILE__, line
            send :#{cmd_name}, *opts, &b
          end
        ], nil, __FILE__, line
      else
        line = __LINE__; eval %[
          def #{cmd_name}(*opts, &b)
            ExtendCommand::#{cmd_class}.execute(irb_context, *opts, &b)
          end
        ], nil, __FILE__, line
      end

      for ali, flag in aliases
        @ALIASES.push [ali, cmd_name, flag]
      end
    end