There are several forms of triggers on the Parse instruction that allow variable usage by wrapping parens around a single variable name:
parse var x a (match) b
for example. The parens are limited to a single variable name, which is a somewhat artificial restriction. Removing this restriction can allow some fairly powerful things to be done with parse. For example,
parse var x "<" tag ">" value ("<\"tag">")
can perform a simple XML tag matchup in a single parse instruction.