simu - retrieve extra data with default value
simu - comment on extra field
ex 5.15 - lazy initialization
ex 5.16 - simu - tracing patch first impl
ex 5.16 - simu - example is working
ex 5.16 - some TODOs
simu & legacy - add primitive odd? even?
ex 5.16 - small program for testing tracing
ex 5.16 - expose trace control
simu & legacy - add print proc to primitive
ex 5.16 - simu - done
ex 5.16 - split controller
ex 5.16 - legacy - impl
ex 5.16 - legacy - simulator online
ex 5.16 - done
ex 5.17 - plan
ex 5.17 - a little more about impl
ex 4.78 & 4.79 - add explicit TODO flag