[kpgiskpg]

I actually started working on a CLI calculator a few days ago that sounds exactly like what you're looking for: https://github.com/Kevinpgalligan/ka

So far it just has variables and basic arithmetic. Other features on my roadmap: rational numbers, a type hierarchy, units, and lazy/smart combinatorics.

What do you imagine the timezone DB would look like? I'd love to hear your ideas!