serialization: again

hi, i'm trying to create a simple form designer. it is, basically, as follows: * "form designer" generates form definitions in xml (btw, is there such a dtd already available?); * "form compiler" parses form definition files and serializes the resulting tree. * php scripts unserialize desired form and send it to the client. being new to php, i've looked through the list archives. there are a lot of discussion threads, focussed mainly on the implementability of one or other method in php. what i'm looking for is a concrete way to implement (un)serializing. i.e., i'm currently stucked on technical problems, that is, how do i flush the data to the disk and how do i restore it. i would be very grateful if anyone could provide me with pointers in that direction. thanks in advance, baurjan.