`It's really dreadful,' she muttered to herself, `the way all the
creatures argue.  It's enough to drive one crazy!'

  The Footman seemed to think this a good opportunity for
repeating his remark, with variations.  `I shall sit here,' he
said, `on and off, for days and days.'

  `But what am I to do?' said Alice.

  `Anything you like,' said the Footman, and began whistling.

Such an empty list is equivalent to the textual substitution of the
first preceding non-empty expression list and its type if any.
Omitting the list of expressions is therefore equivalent to
repeating the previous list.  The number of identifiers must be equal
to the number of expressions in the previous list.
Together with the <a href="#Iota"><code>iota</code> constant generator</a>