2.14 Other Operators in the RHS

Other operators in the RHS aid in rewriting. The first two below are prefixes, which means they must be the first operator in the RHS to have the desired effect. The others are more complex and may appear anywhere in the RHS.

$:

When used as a prefix, proceeds directly to the next rule immediately after the RHS rewrite without trying the LHS again.

$@

When used as a prefix, causes the current rule set to immediately return the result of the RHS rewrite without trying the LHS again (the current rule set exits).

$> set tokens

Passes the tokens that follow through another rule set. The entire expression is replaced with the result of that subroutine call.

$[ host $]

Canonicalizes the hostname contained between this pair of operators. The result is placed into the workspace, and the operators dropped.

$( database key $: default $)

Looks up the key in the database (see Chapter 3, Databases).