Hi, I've found http://www.boost.org/doc/libs/1_44_0/libs/iostreams/doc/tutorial/finite_stat... for filtering stream data. I've got a stream which I would filter with a state filter, because I must check some data and substitute them. Now I try to create a state struct, but I can't compile it, because the headers on the page seems to be not correct. I use a a istream, in which the data saved, now I would send them through the state machine filter for get my output data. My first try was to create the states with a boost::mpl::vector, but the example on the page doesn't work because the compiler can't find the "row" deklaration. Is there an example for a full state filter, that works? Or should I use the boost spirit? I would like to filter my stream data. Thanks for help Phil