June 4th Monday (六月 四日 日曜日)

  'interactive'
     Declare to the interpreter that the function can be used
     interactively.  This special form may be followed by a string with
     one or more parts that pass the information to the arguments of the
     function, in sequence.  These parts may also tell the interpreter
     to prompt for information.  Parts of the string are separated by
     newlines, `/n'.

     Common code characters are:

    'b'
          The name of an existing buffer.

    'f'
          The name of an existing file.

    'p'
          The numeric prefix argument.  (Note that this 'p' is lower
          case.)

    'r'
          Point and the mark, as two numeric arguments, smallest first.
          This is the only code letter that specifies two successive
          arguments rather than one.