Is it possible to use ghci-ng with "stack-ghci" haskell-process-type?

[rrnewton]

I'm trying to get the :type-at based haskell-process-do-type working with stack based projects.

[geraldus]

I'm missing this feature too!

[gracjan]

I do not see a fundamental problem why this should not work. What does *haskell-process-log* say?

[rrnewton]

Well, I can see that *haskell-process-log* says haskell-mode is calling stack ghci.

But, based on stack ghci --help, I don't see any way to change the ghci implementation to use ghci-ng. It does have a --with-ghc option, but stack ghci --with-ghc=ghci-ng is bogus because ghci-ng isn't a full command line replacement for ghc.

[gracjan]

Sounds like an issue report for stack. When you report it there can you post a link here so we know when it is ready?

[chrisdone]

with-ghc is the proper flag, it's just poorly named. I copied this name from cabal-repl. See comment here: commercialhaskell/stack#1024 (comment)

I noticed recently that stack-ghci was added as a supported REPL type, so probably there can be a variable for specifying extra args like in the GHCi case, or otherwise use the wrapper. E.g.

(setq haskell-process-wrapper-function
                    (lambda (args)
                       (append args (list "--with-ghc" "ghci-ng"))))

[rrnewton]

Wow, great, that works.

In this case I had to modify haskell-process-args-stack-ghci to include the --with-ghc option, but now I'm in Haskell IDE paradise being able to use both stack and errors right in my editor buffer...

[da-x]

The version of ghci-ng needs to match the version of GHC, and when you have both 7.10.3 and 7.10.2 as compilers under .stack, then ghci-ng can't just sit in the ~/local/.bin, it needs to sit as two different compiled versions, under ~/.stack/programs/x86_64-linux/ghc-7.10.2/bin and ~/.stack/programs/x86_64-linux/ghc-7.10.3/bin.

My question is, would it our work out of the box for haskell-mode, or do we need to do something else? Where's the best place to put the ghci-ng exe therefore?