Merge pull request #2195 from github/ghci-slowness

Prevent slowdowns when pretty-printing in ghci.

.ghci

@@ -3,7 +3,7 @@
 
 -- See docs/💡ProTip!.md
 :undef pretty
-:def pretty \ _ -> return (unlines [":set -interactive-print Semantic.Util.prettyShow"])
+:def pretty \ _ -> return ":set -interactive-print Semantic.Util.Pretty.prettyShow"
 
 -- See docs/💡ProTip!.md
 :undef no-pretty

semantic.cabal

@@ -197,6 +197,7 @@ library
                      , Semantic.Telemetry.Stat
                      , Semantic.Timeout
                      , Semantic.Util
+                     , Semantic.Util.Pretty
                      , Semantic.Util.Rewriting
                      , Semantic.Version
                      -- Serialization

src/Semantic/Util.hs

@@ -24,8 +24,6 @@ import           Data.List (uncons)
 import           Data.Project hiding (readFile)
 import           Data.Quieterm (quieterm)
 import           Data.Sum (weaken)
-import           Language.Haskell.HsColour
-import           Language.Haskell.HsColour.Colourise
 import           Parsing.Parser
 import           Prologue hiding (weaken)
 import           Semantic.Config
@@ -35,7 +33,7 @@ import           Semantic.Task
 import           Semantic.Telemetry (LogQueue, StatQueue)
 import           System.Exit (die)
 import           System.FilePath.Posix (takeDirectory)
-import           Text.Show.Pretty (ppShow)
+
 
 justEvaluating
   = runM
@@ -145,8 +143,4 @@ mergeExcs = either (\ (SomeExc sum) -> Left (SomeExc (weaken sum))) (either (\ (
 reassociate :: Either (SomeExc exc1) (Either (SomeExc exc2) (Either (SomeExc exc3) (Either (SomeExc exc4) (Either (SomeExc exc5) (Either (SomeExc exc6) (Either (SomeExc exc7) result)))))) -> Either (SomeExc (Sum '[exc7, exc6, exc5, exc4, exc3, exc2, exc1])) result
 reassociate = mergeExcs . mergeExcs . mergeExcs . mergeExcs . mergeExcs . mergeExcs . mergeExcs . Right
 
-
-prettyShow :: Show a => a -> IO ()
-prettyShow = putStrLn . hscolour TTY defaultColourPrefs False False "" False . ppShow
-
 {-# ANN module ("HLint: ignore Reduce duplication" :: String) #-}

src/Semantic/Util/Pretty.hs

@@ -0,0 +1,8 @@
+module Semantic.Util.Pretty (prettyShow) where
+
+import Language.Haskell.HsColour
+import Language.Haskell.HsColour.Colourise
+import Text.Show.Pretty (ppShow)
+
+prettyShow :: Show a => a -> IO ()
+prettyShow = putStrLn . hscolour TTY defaultColourPrefs False False "" False . ppShow