Hi,

I noticed that ob-haskell.el doesn't support custom ghci prompts at present.
Custom ghci prompts such as "λ>" are quite popular in the haskell community, see for example

https://stackoverflow.com/questions/42081379/how-to-set-up-org-babel-for-haskell-with-stack

Could you have a look at the following patch and see, wether that would work in general, wrt. coding standars etc.
Obviously it works on my system, but I'm not an experienced elisp programmer, so I guess there might be  room for
improvement.