Collaborating on improving the REPL evaluator

[natefaubion]

It appears that both Aff code and <- work in the repl in a :paste block. But in this case, all three lines are printed after the delay. Maybe this is really just Effect code with the launchAff_ . Is the goal of these enhancements to get this working without the :paste block, and have the print timing work as expected?

I mean <- as a top-level repl binding, so you can do:

> a <- readFile "file.txt"

And a would be in scope for future repl calls. The repl currently does not let you evaluate effectful code, and maintain a binding to its result.