Have you tried writing Haskell in the repl? I would argue that just omitting the types (essentially var:ing everything) would still make a repl very valuable for trying stuff out while you write your code. When I worked at citrix I would debug constantly in ironpython and I would find and fix bugs 5 times faster than my coworkers that would write clunky command line programs.. A repl is a very powerful tool that any nimble dev should take seriously.