OSSP var is a flexible, full-featured and fast variable construct expansion
library. It supports a configurable variable construct syntax very similar
to the style found in many scripting languages (like @name, ${name}, , etc.)
and provides both simple scalar (${name}) and array (${name[index]})
expansion, plus optionally one or more post-operations on the expanded value
(${name:op:op...}).

WWW: http://www.ossp.org/pkg/lib/var/