Well, there's: - Dependently typed languages (ATS, Agda, Idris)¹ should be fairly familiar if you're a Haskell veteran. - Array languages (APL, J, K, and more

Well, there's: - Dependently typed languages (ATS, Agda, Idris)¹ should be fairly familiar if you're a Haskell veteran. - Array languages (APL, J, K, and more obscure ones like Nial) are pretty enlightening if you're a functional programmer (at least they are for me). Most of these trace to Ken Iverson and his Notation as a Tool of Thought. They are a bit brain-bending at first, largely because of the density, but they're fun to use and the density makes comprehension easier after a while. - Function-level languages (FL, FPr, J) – a somewhat obscure and very advanced sister to functional programming. If you're familiar with Haskell Arrows, there are many parallels. They are, essentially, a more convenient point-free style. Most (all?) of these trace to John Backus (of Fortran and Backus-Naur Form fame) and his 1977 Turing Award lecture Can Programming Be Liberated From the von Neumann Style? J (http://jsoftware.com/ http://jsoftware.com/) combines array and function-level programming, and IMO is a very good language to learn to expand your horizons if you're a veteran functional programmer. -- ¹ Coq kinda, but it's more of a theorem prover than a programming language. Agda sort of fits that too.