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I think ghci is one of the best repls out there: - :type and :info - :doc - Debugger + breakpoints - :print :sprint for understanding laziness - Can run sh

I think ghci is one of the best repls out there: - :type and :info - :doc - Debugger + breakpoints - :print :sprint for understanding laziness - Can run shell commands with :! - Can set different compilation flags for the loaded code vs the repl session. - Can define your own repl commands I use ghci for developing standalone modules, running HTTP servers, and running unit tests. The biggest thing I wish it had was something like chez scheme's `trace`, which causes it to print out a function with its arguments every time it is called.

dllthomas 6y ago
I like GHCi, but it's definitely missing some things if we're talking about using a REPL for development rather than just experimentation (which is a valuable thing itself). The two biggest things, I think, are: 1) GHCi allows rebinding symbols, which is great, but it doesn't have good mechanisms for propagating that change. Haskell being Haskell, I don't really expect change local binding to propagate to everywhere that binding has been used. But it would be great if I could point at an identifier I've declared and say "redefine everything that was used to get here". 2) The path from REPL to source code in a file is very manual. I often find myself copying code out of my history, and have to manually remove bindings that I've shadowed since. The tooling that it does provide, though, is really great :)