> When storing time, store Unix time. It's a single number.
This won't work for any system that allows users to schedule events in the future. Let's say that you agree for a meeting in Moscow 1 dec 2013 3pm. The actual (astronomical) time of meeting might change significantly if they change daylight saving rules. So you need to store something like "2013-12-01 15:00 Moscow", there's no way around it.
Have you got a good example where Lisp macros would work but standard Haskell would "fail"?
I've done some compiler work in Haskell like writing programs (semantic actions) as algebraic data structures and then transforming or interpreting the tree. Would I gain something by using Lisp macros in this instance?
This won't work for any system that allows users to schedule events in the future. Let's say that you agree for a meeting in Moscow 1 dec 2013 3pm. The actual (astronomical) time of meeting might change significantly if they change daylight saving rules. So you need to store something like "2013-12-01 15:00 Moscow", there's no way around it.