Ever wished that you had feature X in language Y? Frustrated that two libraries don’t play nice together? Have framework fatigue? Language design principles also extend to libraries. This is especially true when porting concepts and features from another language or ecosystem. In this follow-up to her Empex 2018 keynote, Brooklyn will explore a philosophy of library design with an eye towards porting, drawing concretely from her experiences bootstrapping features primarily inspired by Haskell and OCaml to Elixir. Which factors do you need to balance, when is it appropriate to deviate from the core syntax (of both source and target), and importantly: how far can you bend before you break?