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 <some.big.long.domain>:

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 $digit operator.