Config for GHCi with pretty output

ghci.conf

-- To run: 
--    cabal repl -b pretty-simple
--
-- Colorizing and pretty-printing ghci output
-- requires: pretty-simple
:set -interactive-print=Text.Pretty.Simple.pPrint

-- green bold lambdas and multiline mode
:set prompt      "\ESC[1;32mλ: \ESC[m"
:set prompt-cont "\ESC[1;32mλ| \ESC[m"

-- useful flags
:set -fprint-explicit-foralls
:set +m

-- useful extensions by default
:set -XTypeApplications -XKindSignatures

-- useful default imports
import Data.Kind (Type, Constraint)

-- helpful macros
:def package \ m -> return $ ":! ghc-pkg --simple-output find-module " ++ m
:def no-pretty \_ -> return (":set -interactive-print=System.IO.print")
:def rr \_ -> return ":script ~/.ghc/ghci.conf"

How can I use this in a project?

I have to specify the package.

stack ghci --package pretty-show --package hscolour --package heredoc

And I run stack ghci, it will be override. Loaded GHCi configuration from /tmp/haskell-stack-ghci/f00796c9/ghci-script

Hi @AurevoirXavier, I no longer use this particular GHCi config. My new global GHCi config is much smaller. Also, I'm now using cabal almost all the time for development instead of stack. Cabal doesn't have such an issue, I can run cabal repl -b pretty-simple from any place and any project and it will work automatically. I've updated this gist to reflect my latest config and not confuse people in the future 🙂

I found the problem. The :load will drop pre define things something like ghciColor.
pretty-simple sounds like a good solution.

Here's my modification. It also works for stack, whatever you're under a stack project or not.

Thanks @chshersh

:def pretty \_ -> return (":set -interactive-print=Text.Pretty.Simple.pPrint")
:def no-pretty \_ -> return (":set -interactive-print System.IO.print")

:def package \m -> return $ ":! ghc-pkg --simple-output find-module " ++ m
:def rr \_ -> return ":script ~/.ghci"

:set prompt  "\ESC[1;32mλ \ESC[m"

:set +m
:set +s
:set +t

:set -package pretty-simple

:set -fprint-explicit-foralls
:set -interactive-print=Text.Pretty.Simple.pPrint
:set -XTypeApplications -XKindSignatures

import Data.Kind (Type, Constraint)