[kowainik#18] Add LazyStrict type class (kowainik#33)

* [kowainik#18] Add LazyStrict type class

* Remove map = fmap, reexport from Data.List

CHANGELOG.md

@@ -26,6 +26,9 @@ Change log
   `whenLeft_` and `whenRight_`, `whenLeftM_` and `whenRightM_`.
   Add `whenLeft`, `whenRight`, `whenLeftM`, `whenRightM` which return
   the value.
+* [#18](https://github.com/kowainik/universum/issues/18):
+  Add `LazyStrict` type class for conversions.
+* `map` is not `fmap` anymore. Reexport `map` from `Data.List`
 
 
 `universum` uses [PVP Versioning][1].

README.md

@@ -125,7 +125,6 @@ Gotchas [↑](#structure-of-this-tutorial)
 * `head`, `tail`, `last`, `init` work with `NonEmpty a` instead of `[a]`.
 * Safe analogue for `head` function: `safeHead :: [a] -> Maybe a`.
 * `undefined` triggers a compiler warning, which is probably not what you want. Either use `throwIO`, `Except`, `error` or `bug`.
-* `map` is `fmap` now.
 * Multiple sorting functions are available without imports:
   + `sortBy :: (a -> a -> Ordering) -> [a] -> [a]`: sorts list using given custom comparator.
   + `sortWith :: Ord b => (a -> b) -> [a] -> [a]`: sorts a list based on some property of its elements.

src/Universum/Functor/Fmap.hs

@@ -1,33 +1,21 @@
 {-# LANGUAGE Safe #-}
 
+{-
+Copyright: (c) 2016 Stephen Diehl
+           (c) 20016-2018 Serokell
+           (c) 2018 Kowainik
+License: MIT
+-}
+
 -- | This module contains useful functions to work with 'Functor' type class.
 
 module Universum.Functor.Fmap
-       ( map
-       , (<<$>>)
+       ( (<<$>>)
        ) where
 
 import Universum.Function ((.))
 import Universum.Functor.Reexport (Functor (..))
 
--- $setup
--- >>> import Universum.Base (negate)
--- >>> import Universum.Bool (Bool (..), not)
--- >>> import Universum.Lifted (getLine)
--- >>> import Universum.Monad (Maybe (..))
--- >>> import Universum.String (toString)
-
-{- | 'Prelude.map' generalized to 'Functor'.
-
->>> map not (Just True)
-Just False
->>> map not [True,False,True,True]
-[False,True,False,False]
-
--}
-map :: Functor f => (a -> b) -> f a -> f b
-map = fmap
-
 -- $setup
 -- >>> import Universum.Base (negate)
 -- >>> import Universum.Monad (Maybe (..))

src/Universum/List/Reexport.hs

@@ -10,8 +10,8 @@ module Universum.List.Reexport
 
 import Data.List (break, cycle, drop, dropWhile, filter, genericDrop, genericLength,
                   genericReplicate, genericSplitAt, genericTake, group, inits, intercalate,
-                  intersperse, isPrefixOf, iterate, permutations, repeat, replicate, reverse, scanl,
-                  scanr, sort, sortBy, sortOn, splitAt, subsequences, tails, take, takeWhile,
+                  intersperse, isPrefixOf, iterate, map, permutations, repeat, replicate, reverse,
+                  scanl, scanr, sort, sortBy, sortOn, splitAt, subsequences, tails, take, takeWhile,
                   transpose, unfoldr, unzip, unzip3, zip, zip3, zipWith, (++))
 import Data.List.NonEmpty (NonEmpty (..), head, init, last, nonEmpty, tail)
 

src/Universum/String/Conversion.hs

@@ -1,8 +1,9 @@
-{-# LANGUAGE CPP                   #-}
-{-# LANGUAGE ExplicitForAll        #-}
-{-# LANGUAGE FlexibleInstances     #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE TypeSynonymInstances  #-}
+{-# LANGUAGE CPP                    #-}
+{-# LANGUAGE ExplicitForAll         #-}
+{-# LANGUAGE FlexibleInstances      #-}
+{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE MultiParamTypeClasses  #-}
+{-# LANGUAGE TypeSynonymInstances   #-}
 
 {-
 Copyright: (c) 2016 Stephen Diehl
@@ -27,6 +28,9 @@ module Universum.String.Conversion
        , ToString (..)
        , ToLText (..)
        , ToText (..)
+       , LazyStrict (..)
+       , fromLazy
+       , fromStrict
 
          -- * Show and read functions
        , readEither
@@ -183,3 +187,33 @@ show x = fromString (Show.show x)
 {-# SPECIALIZE show :: Show.Show  a => a -> ByteString  #-}
 {-# SPECIALIZE show :: Show.Show  a => a -> LByteString  #-}
 {-# SPECIALIZE show :: Show.Show  a => a -> String  #-}
+
+
+-- | Type class for lazy-strict conversions.
+class LazyStrict l s | l -> s, s -> l where
+    toLazy :: s -> l
+    toStrict :: l -> s
+
+fromLazy :: LazyStrict l s => l -> s
+fromLazy = toStrict
+{-# INLINE fromLazy #-}
+{-# SPECIALIZE fromLazy :: LByteString -> ByteString  #-}
+{-# SPECIALIZE fromLazy :: LText -> Text  #-}
+
+fromStrict :: LazyStrict l s => s -> l
+fromStrict = toLazy
+{-# INLINE fromStrict #-}
+{-# SPECIALIZE fromStrict :: ByteString -> LByteString  #-}
+{-# SPECIALIZE fromStrict :: Text -> LText  #-}
+
+instance LazyStrict LByteString ByteString where
+    toLazy = LB.fromStrict
+    {-# INLINE toLazy #-}
+    toStrict = LB.toStrict
+    {-# INLINE toStrict #-}
+
+instance LazyStrict LText Text where
+    toLazy = LT.fromStrict
+    {-# INLINE toLazy #-}
+    toStrict = LT.toStrict
+    {-# INLINE toStrict #-}

src/Universum/String/Reexport.hs

@@ -6,7 +6,6 @@ module Universum.String.Reexport
 
          -- * Text
        , module Data.Text
-       , module Data.Text.Lazy
        , module Data.Text.Encoding
        , module Data.Text.Encoding.Error
        , module Text.Read
@@ -21,5 +20,4 @@ import Data.Text (Text, lines, unlines, unwords, words)
 import Data.Text.Encoding (decodeUtf8', decodeUtf8With)
 import Data.Text.Encoding.Error (OnDecodeError, OnError, UnicodeException, lenientDecode,
                                  strictDecode)
-import Data.Text.Lazy (fromStrict, toStrict)
 import Text.Read (Read, readMaybe, reads)