The conjunction !: applies to integer scalar left
and right arguments to produce verbs, with the exception that
the case 5!:0 produces an adverb.
These verbs behave like any other verb: they may be assigned names,
may serve as arguments to adverbs and conjunctions,
and must be used with an argument even though (as in 6!:0 '')
it may have no significance.
Where these verbs take names as arguments,
the names are boxed, as in 4!:55 'a';'bc' to erase
the names a and bc .
A bracketed left argument indicates that it is optional.