[Boost-users] Spirit guidance needed

Hi all, Can somebody direct me to a part/facility inside the Spirit library to do the following: I need to pre-parce a boolean expression (once) and save it somewhere. Then I need to evaluate this expression (many times, performance important) based on different values of tokens. Will Spirit.Classic do? Or do I need to use any of the newer libraries inside Spirit? Thanks for any help. Arkadiy