The idea behind bc is to display partial results to the right of the cursor in yellow while we type. A little example can be found in the video above. Other than that, we want to be compatible with the original bc, though somewhat faster. We have infinite precision integers and double precision floats.

TODO

Basically everything except numbers, variables, and if. This includes:

A complete parser (foundations are laid)
A better evaluator (the current just does a tree rewrite on binary operations; this is cute, but not capable enough for the full bc language, of course)
A good readline copy (haskeline is sadly out of the question for this project)