[Template-haskell] Need specific examples of TH use

Could someone please point me to working examples of TH usage to manipulate with class instances and data structures? A typical example of what I want to try: collect specific subset of instances of some class and construct some code iterating over each instance in the subset. To clarify: I want to try to add some TH capabilities to HSFFIG: subset of instances represents an imported C structure; a code to generate may be e. g. peeker/poker for a structure, or a serializer, or anything else. I am hoping, that's what metaprogramming is for ;) Thanks. -- Dimitry Golubovsky Anywhere on the Web