UDF udf=config.getFromFunctionCache(key);
if(udf!=null) return udf;
Mapping mapping=isweb?config.getFunctionMapping():config.getServerFunctionMapping();
PageSourceImpl ps = (PageSourceImpl) mapping.getPageSource(filename);
Page p = ps.loadPage(pc);
// execute page
Variables old = pc.variablesScope();
pc.setVariablesScope(VAR);