hello all: I have the following code: #define REGISTER_MODULE(module)(\ #ifdef BOOST_PP_EQUAL(BOOST_PP_LIST_SIZE(MODULES), 0)\ //there are currently no modules in the list. #define MODULES((module), BOOST_PP_NIL) #else BOOST_PP_LIST_APPEND(MODULES, module)\ #endif ) I am somewhat of a newb at preprocessor magic, so any advice would be useful. For whatever reason this translates out to 'module)' when I try to compile it with -E -P. The idea is that it will add to the modules list (assuming the modules list exists) the module to be registered, which should just be a type. Thanks, -- Take care, Ty http://tds-solutions.net The aspen project: a barebones light-weight mud engine: http://code.google.com/p/aspenmud He that will not reason is a bigot; he that cannot reason is a fool; he that dares not reason is a slave.