Proceedings of the SIGPLAN Conference on Programming Language Design and Implementation
Author's Final Manuscript
Parametric polymorphism is one of the linchpins of modern typed programming, but it comes with a real performance penalty. We describe this penalty; offer a principled way to reason about it (kinds as calling conventions); and propose levity polymorphism. This new form of polymorphism allows abstractions over calling conventions; we detail and verify restrictions that are necessary in order to compile levity-polymorphic functions. Levity polymorphism has created new opportunities in Haskell, including the ability to generalize nearly half of the type classes in GHC's standard library.
R.A. Eisenberg and S. Peyton Jones 2017. "Levity Polymorphism." Proceeding PLDI 2017 Proceedings of the 38th ACM SIGPLAN Conference on Programming Language Design and Implementation: 525-539.