Things I learned making Instant compiler

Few things I learned making Instant compiler

Instant compiler was translating statements like: "x=1; y=1; x + y". It was teaser for Latte compiler

1. Working with BNFC is hard because it generates a lot of boilerplate that cannot be changed. I could replace it with Parsec.
2. I had some problems with case .. of ... At the end case tree were quite big. Solution: Monad transformers
3. Creating proper strings was awful. Printf like function could be handy
4. Automated tests are important
5. Some form of CI/CD could be nice