The next arg is ignored.
~n* ignores the next n arguments.
~:* backs up in the list of
arguments so that the argument last processed will be processed again.
~n:* backs up n arguments.
When within a ~{ construct
(see below), the ignoring (in either direction) is relative to the list
of arguments being processed by the iteration.
~n@*
goes to the nth arg, where 0 means the first one;
n defaults to 0, so ~@* goes back to the first arg.
Directives after a ~n@*
will take arguments in sequence beginning with the one gone to.
When within a ~{ construct, the "goto"
is relative to the list of arguments being processed by the iteration.