both (empty) → 0.1.0.0

raw patch · 4 files changed

+114/−0 lines, 4 filesdep +basesetup-changed

Dependencies added: base

Files

• Data/Both.hs +39/−0
• LICENSE +20/−0
• Setup.hs +2/−0
• both.cabal +53/−0

@@ -0,0 +1,39 @@+{-# LANGUAGE DeriveDataTypeable         #-}+{-# LANGUAGE DeriveGeneric              #-}+{-# LANGUAGE DeriveTraversable          #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}++-- | The 'Both' type and operations. Like 'Maybe', but not.+module Data.Both where++import Control.Applicative+import Control.Monad+import Data.Data+import Data.Foldable+import Data.Maybe+import Data.Monoid+import Data.Traversable+import GHC.Generics++newtype Both a = Both { getBoth :: Maybe a }+  deriving (Eq, Ord, Read, Show, Data, Typeable, Generic, Generic1, Functor, Applicative, Alternative, Monad, MonadPlus, Foldable, Traversable)++-- | The 'mappend' for 'Maybe' is 'Just' if /either/ of the operands+-- are, whereas here /both/ must be.+instance Monoid a => Monoid (Both a) where+  mempty = Both $ Just mempty+  mappend (Both (Just x)) (Both (Just y)) = Both . Just $ x <> y+  mappend _ _ = Both Nothing++-- | The 'both' function takes a default value, a function, and a+-- 'Both' value. If the inner 'Maybe' value is 'Nothing', the function+-- returns the default value. Otherwise, it applies the function to+-- the value inside the 'Just' and returns the result.+both :: b -> (a -> b) -> Both a -> b+both z f = maybe z f . getBoth++-- | The 'fromBoth' function takes a default value and a 'Both'+-- value. If the inner 'Maybe' is 'Nothing', it returns the default+-- value; otherwise, it returns the value contained within.+fromBoth :: a -> Both a -> a+fromBoth z = fromMaybe z . getBoth

@@ -0,0 +1,20 @@+Copyright (c) 2015, Michael Walker <mike@barrucadu.co.uk>++Permission is hereby granted, free of charge, to any person obtaining+a copy of this software and associated documentation files (the+"Software"), to deal in the Software without restriction, including+without limitation the rights to use, copy, modify, merge, publish,+distribute, sublicense, and/or sell copies of the Software, and to+permit persons to whom the Software is furnished to do so, subject to+the following conditions:++The above copyright notice and this permission notice shall be+included in all copies or substantial portions of the Software.++THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,53 @@+-- Initial both.cabal generated by cabal init.  For further documentation, +-- see http://haskell.org/cabal/users-guide/++name:                both+version:             0.1.0.0+synopsis:            Like Maybe, but with a different Monoid instance.+description:+  The Monoid instance for Maybe behaves like so:+  .+  > instance Monoid a => Monoid (Maybe a) where+  >   mappend (Just x) (Just y) = Just $ x <> y+  >   mappend (Just x) Nothing  = Just x+  >   mappend Nothing  (Just y) = Just y+  >   mappend Nothing  Nothing  = Nothing+  >+  >   mempty = Nothing+  .+  Both is a newtype wrapper around Maybe providing this instance:+  .+  > instance Monoid a => Monoid (Both a) where+  >   mappend (Just x) (Just y) = Just $ x <> y+  >   mappend _ _ = Nothing+  >+  >   mempty = Just mempty++homepage:            https://github.com/barrucadu/both+bug-reports:         https://github.com/barrucadu/both/issues+license:             MIT+license-file:        LICENSE+author:              Michael Walker+maintainer:          mike@barrucadu.co.uk+-- copyright:           +category:            Data+build-type:          Simple+-- extra-source-files:  +cabal-version:       >=1.10++source-repository head+  type:     git+  location: https://github.com/barrucadu/both.git++source-repository this+  type:     git+  location: https://github.com/barrucadu/both.git+  tag:      0.1.0.0++library+  exposed-modules:     Data.Both+  -- other-modules:       +  -- other-extensions:    +  build-depends:       base >=4.7 && <4.9+  -- hs-source-dirs:      +  default-language:    Haskell2010