witch 0.2.0.2 → 0.2.1.0

raw patch · 5 files changed

+121/−8 lines, 5 filesdep +QuickCheckPVP ok

version bump matches the API change (PVP)

Dependencies added: QuickCheck

API changes (from Hackage documentation)

Files

• README.markdown +1/−1
• src/lib/Witch.hs +5/−0
• src/lib/Witch/Casting.hs +62/−0
• src/test/Main.hs +50/−6
• witch.cabal +3/−1

@@ -1,6 +1,6 @@ # Witch -[![CI](https://github.com/tfausak/witch/workflows/CI/badge.svg)](https://github.com/tfausak/witch/actions/new)+[![CI](https://github.com/tfausak/witch/workflows/CI/badge.svg)](https://github.com/tfausak/witch/actions) [![Hackage](https://img.shields.io/hackage/v/witch)](https://hackage.haskell.org/package/witch) [![Stackage](https://www.stackage.org/package/witch/badge/nightly?label=stackage)](https://www.stackage.org/package/witch) 

@@ -159,9 +159,14 @@   , Witch.Lift.liftedCast   , Witch.Lift.liftedFrom   , Witch.Lift.liftedInto++  -- * Data types+  -- ** Casting+  , Witch.Casting.Casting(Casting)   ) where  import qualified Witch.Cast+import qualified Witch.Casting import Witch.Instances () import qualified Witch.Lift import qualified Witch.TryCast

@@ -0,0 +1,62 @@+{-# LANGUAGE FlexibleInstances #-}+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeApplications #-}++module Witch.Casting where++import qualified Data.Bifunctor as Bifunctor+import qualified Data.Function as Function+import qualified Witch.Cast as Cast++-- | This type mostly exists to make it easier to derive instances through+-- some other type. It does this by leaning on the 'Cast.Cast' type class. For+-- example, consider this data type:+--+-- > data Toggle = Off | On+-- > instance Cast Toggle String where+-- >   cast toggle = case toggle of+-- >     Off -> "off"+-- >     On -> "on"+--+-- If you wanted to implement a 'Show' instance for @Toggle@ by going through+-- a 'String', you would need to write something like this:+--+-- > instance Show Toggle where+-- >   show = show . into @String+--+-- That may not very complicated, but at the same time it is not very+-- interesting. And it can be tricky if you want to keep other instances (like+-- 'Read') in sync. That's where the 'Casting' type comes in! You can+-- derive the above instance like so:+--+-- > data Toggle = Off | On+-- >   deriving Show via Casting Toggle String+newtype Casting source target+  = Casting source++-- | Uses @coerce@.+instance Cast.Cast s (Casting s t)++-- | Uses @coerce@.+instance Cast.Cast (Casting s t) s++instance (Cast.Cast t s, Bounded t) => Bounded (Casting s t) where+  maxBound = Cast.cast $ Cast.cast @t @s maxBound+  minBound = Cast.cast $ Cast.cast @t @s minBound++instance (Cast.Cast s t, Cast.Cast t s, Enum t) => Enum (Casting s t) where+  fromEnum = fromEnum . Cast.cast @s @t . Cast.cast+  toEnum = Cast.cast . Cast.cast @t @s . toEnum++instance (Cast.Cast s t, Eq t) => Eq (Casting s t) where+  (==) = Function.on (==) $ Cast.cast @s @t . Cast.cast++instance (Cast.Cast s t, Ord t) => Ord (Casting s t) where+  compare = Function.on compare $ Cast.cast @s @t . Cast.cast++instance (Cast.Cast t s, Read t) => Read (Casting s t) where+  readsPrec = fmap (fmap . Bifunctor.first $ Cast.cast . Cast.cast @t @s) . readsPrec++instance (Cast.Cast s t, Show t) => Show (Casting s t) where+  show = show . Cast.cast @s @t . Cast.cast

@@ -1,3 +1,4 @@+{-# LANGUAGE DerivingVia #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE TemplateHaskell #-}@@ -23,6 +24,9 @@ import qualified Data.Word as Word import qualified Numeric.Natural as Natural import qualified Test.Hspec as Hspec+import qualified Test.Hspec.QuickCheck as Hspec+import Test.QuickCheck ((===))+import qualified Text.Read as Read import qualified Witch  main :: IO ()@@ -52,7 +56,7 @@       test $ Witch.into @Int.Int16 (1 :: Int.Int8) `Hspec.shouldBe` 1      Hspec.describe "over" $ do-      test $ Witch.over @String (<> "!") (Name "Kiki") `Hspec.shouldBe` Name "Kiki!"+      test $ Witch.over @Int.Int8 (+ 1) (Age 1) `Hspec.shouldBe` Age 2      Hspec.describe "via" $ do       test $ Witch.via @Int.Int16 (1 :: Int.Int8) `Hspec.shouldBe` (1 :: Int.Int32)@@ -1655,6 +1659,46 @@       let f = Witch.cast @(Witch.TryCastException Bool Int) @LazyText.Text       test $ f (Witch.TryCastException False Nothing) `Hspec.shouldBe` LazyText.pack "TryCastException @Bool @Int False Nothing" +  -- Casting++  Hspec.describe "Casting" $ do++    Hspec.describe "Bounded" $ do++      Hspec.it "maxBound" $ do+        maxBound `Hspec.shouldBe` Age maxBound++      Hspec.it "minBound" $ do+        minBound `Hspec.shouldBe` Age minBound++    Hspec.describe "Enum" $ do++      Hspec.prop "fromEnum" $ \x ->+        fromEnum (Age x) === fromEnum x++      Hspec.prop "toEnum" $ \x ->+        toEnum x === Age (toEnum x)++    Hspec.describe "Eq" $ do++      Hspec.prop "==" $ \x ->+        Age x === Age x++    Hspec.describe "Ord" $ do++      Hspec.prop "compare" $ \x y ->+        compare (Age x) (Age y) === compare x y++    Hspec.describe "Read" $ do++      Hspec.prop "readMaybe" $ \x ->+        Read.readMaybe x === fmap Age (Read.readMaybe x)++    Hspec.describe "Show" $ do++      Hspec.prop "show" $ \x ->+        show (Age x) === show x+ test :: Hspec.Example a => a -> Hspec.SpecWith (Hspec.Arg a) test = Hspec.it "" @@ -1670,10 +1714,10 @@  instance Exception.Exception Untested -newtype Name-  = Name String-  deriving (Eq, Show)+newtype Age+  = Age Int.Int8+  deriving (Bounded, Enum, Eq, Ord, Read, Show) via Witch.Casting Age Int.Int8 -instance Witch.Cast Name String+instance Witch.Cast Age Int.Int8 -instance Witch.Cast String Name+instance Witch.Cast Int.Int8 Age

@@ -1,7 +1,7 @@ cabal-version: 2.2  name: witch-version: 0.2.0.2+version: 0.2.1.0 synopsis: Convert values from one type into another. description: Witch converts values from one type into another. @@ -46,6 +46,7 @@   exposed-modules:     Witch     Witch.Cast+    Witch.Casting     Witch.Identity     Witch.Instances     Witch.Lift@@ -67,6 +68,7 @@    build-depends:     , hspec >= 2.7.9 && < 2.8+    , QuickCheck >= 2.14.2 && < 2.15     , witch   ghc-options:     -rtsopts