[add1] and [add2].
[add1] and [add2].

It has hit a point that proving properties is no longer fun. I have to keep adding properties about [balanceL] and [balanceR], and writing the proofs are hardly pleasant. Though the proofs are mostly very straightforward, they are also quite tedious -- I have to repeat doing case analyses on subtrees. Even though we can define some tactics that can make proofs significantly shorter, I have to define different tactics for each different properties... I feel there are something more general I'm missing.

antalsz/hs-to-coq,antalsz/hs-to-coq