GHCi output is not machine readable

[CrystalSplitter]

Even with GHCiD, GHCi responses are simply not machine parseable. There's no reliable grammar and there's no escape support. This is most obvious with the :show bindings GHCi builtin command with multi-line nested strings.

This is an upstream issue inherently, but is likely something we can provide a compelling need for and contribute the source code. A simple JSON reply (or some other format) seems easy enough to implement.

I would prefer not to ship with a custom version of GHC, so upstreaming such an effort is likely the only course of action here.

[Uberoverlord]

looking into this it would seem there are already efforts in creating a machine readable interface for the debugger with this version of ghci. Perhaps this could be of use?

[CrystalSplitter]

That's a good starting point actually, yeah! It seems very experimental with not much documentation, but reading through haskell-dap, the interface doesn't seem too bad. Might be able to just run it and watch the output.

I was hoping for some upstream implementation, but at least a standard with a very clearly documented specification is very useful.

[CrystalSplitter]

Coming back to this after trying to playing around with it.

Both ghci-dap and haskell-dap alone are unfortunately very poorly documented, and their usage is... confusing to say the least. However, haskell-debug-adapter does give some example usages. Admittedly, it does feel somewhat unstable, but perhaps I can reach out and get some ideas API usage?