The $* operator is a wildcard operator. It is used
to match zero or more tokens in the workspace. One handy use for it
is to honor a pair of angle braces, regardless of whether that pair
has something between them. The following LHS, for example, will
match <>, or
<wash>, or even
R < $* > ...
But because $* can match an unexpected number of
tokens, it is wise to understand minimum matching before using it.
See Section 18.6.1 for a discussion of minimum matching
and the backup and retry process.
Note that the $* operator can be used only on the
LHS of rules, and can be referenced by an RHS