I'd add one other feature of Haskell- and ML-style type systems that I like: they provide clear, succinct, convenient ways to precisely describe data structures

I'd add one other feature of Haskell- and ML-style type systems that I like: they provide clear, succinct, convenient ways to precisely describe data structures. Common Lisp is far and away my favorite surviving programming language, but I like Haskell and ML fairly well. I mean, when I've been paid to work in them, I definitely missed working in Lisp, but still, working in Haskell and ML is not torture. I liked it quite a bit better than working in some other languages. One of the things I liked was the ability to succinctly express in some detail exactly what I intend some data structure to be. I've even used Haskell as a data-description language to work out some data structure that I then implemented in Lisp. I keep intending to do something with Coalton for this reason alone.