Merge pull request #2331 from github/add-fromright-fromleft

Add fromRight/fromLeft to Prologue and according hlint rules.

.hlint.yaml

@@ -67,6 +67,8 @@
 
 # Conveniences
 - warning: {lhs: maybe a pure, rhs: maybeM a, name: Use maybeM}
+- warning: {lhs: either (const a) id, rhs: fromRight a, name: use fromRight}
+- warning: {lhs: either id (const a), rhs: fromLeft a, name: use fromRight}
 
 # Applicative style
 - warning: {lhs: f <$> pure a <*> b, rhs: f a <$> b, name: Avoid redundant pure}

src/Data/ImportPath.hs

@@ -2,21 +2,23 @@
 module Data.ImportPath (IsRelative(..), ImportPath(..), importPath, toName, defaultAlias) where
 
 import Prologue
+
 import           Data.Aeson
 import qualified Data.Text as T
-import Data.Abstract.Name
 import           Proto3.Suite
 import qualified Proto3.Wire.Decode as Decode
 import qualified Proto3.Wire.Encode as Encode
-import           Data.Abstract.Path (stripQuotes)
 import           System.FilePath.Posix
 
+import Data.Abstract.Name
+import Data.Abstract.Path (stripQuotes)
+
 data IsRelative = Unknown | Relative | NonRelative
   deriving (Bounded, Enum, Finite, MessageField, Named, Eq, Generic, Hashable, Ord, Show, ToJSON, NFData)
 
 instance Primitive IsRelative where
   encodePrimitive = Encode.enum
-  decodePrimitive = either (const def) id <$> Decode.enum
+  decodePrimitive = fromRight def <$> Decode.enum
   primType _ = Named (Single (nameOf (Proxy @IsRelative)))
 
 instance HasDefault IsRelative where

src/Prologue.hs

@@ -16,6 +16,7 @@ import Data.Bits as X
 import Data.ByteString as X (ByteString)
 import Data.Coerce as X
 import Data.Functor.Both as X (Both (Both), runBothWith)
+import Data.Either as X (fromLeft, fromRight)
 import Data.IntMap as X (IntMap)
 import Data.IntSet as X (IntSet)
 import Data.Ix as X (Ix (..))