My long posts were intended, in part, to expose my assumptions for correction if needed. Here are what I conceive to be the key questions about psyco: 1. How often and under what circumstances does psyco_compatible get called? My _guess_ is that it gets called once per every invocation of every "psycotic" function (function optimized by psyco). Is this correct? 2. True or false: the call to psyco_compatible would be equivalent to runtime code that discovers special values of certain particular variables. 3. True or false: adding more state information to psyco (in order to discover more runtime values) will slow down psyco_compatible. 4. Are these the most important questions to ask about psyco? If not, what _are_ the key questions? Thanks very much. Edward -------------------------------------------------------------------- Edward K. Ream email: edream@tds.net Leo: Literate Editor with Outlines Leo: http://personalpages.tds.net/~edream/front.html --------------------------------------------------------------------