plur 0.1.0.0 → 0.2.0.0

raw patch · 4 files changed

+87/−24 lines, 4 filesdep +hedgehogdep +hedgehog-classesdep +plurdep ~base

Dependencies added: hedgehog, hedgehog-classes, plur

Dependency ranges changed: base

Files

• ChangeLog.md +7/−1
• plur.cabal +26/−4
• src/Data/Plur.hs +23/−19
• test/Properties.hs +31/−0

@@ -1,5 +1,11 @@ # Revision history for plur -## 0.1.0.0  -- YYYY-mm-dd+## 0.2.0.0 -- 2019-02-12++Breaking changes: made all fields strict++Other stuff: Added documentation for `Plur` and `count`.++## 0.1.0.0 -- 2018-05-24  * First version. Released on an unsuspecting world.

@@ -1,21 +1,43 @@ name:                plur-version:             0.1.0.0+version:             0.2.0.0 synopsis:            Plurality monad: Zero, one, or at least two.--- description:+description:+  Often when counting you don't need an exact count, but only whether there are+  two things. Two examples:+  .+  When searching for inhabitants of a type (implementations of a program), you+  want to be able to tell whether there are (a) no possible inhabitants, (b) a+  unique inhabitant, or (c) multiple inhabitants.+  .+  When displaying the name of a variable, if there's exactly one variable of a+  given name ("a") you can just use that name, but if there are multiples you+  might use a unique id to disambiguate them ("a1" vs "a2"). license:             BSD3 license-file:        LICENSE author:              Joel Burget maintainer:          joelburget@gmail.com-copyright:           (c) 2018 Joel Burget+copyright:           (c) 2018-2019 Joel Burget category:            Data build-type:          Simple extra-source-files:  ChangeLog.md cabal-version:       >=1.10+tested-with:         GHC == 8.6.3  library   exposed-modules:     Data.Plur   build-depends:-    base >=4.11 && <4.12,+    base >=4.3 && <4.14,     semigroups >= 0.18   hs-source-dirs:      src   default-language:    Haskell2010++test-suite Properties+  type:             exitcode-stdio-1.0+  hs-source-dirs:   test+  main-is:          Properties.hs+  build-depends:+    base,+    plur,+    hedgehog,+    hedgehog-classes >= 0.1.1+  default-language: Haskell2010

@@ -1,18 +1,20 @@-{-# language LambdaCase #-} module Data.Plur (Plur(..), count) where +import Control.Applicative+import Data.Foldable import Data.Monoid-import Data.Semigroup+import Data.Semigroup as Semigroup+import Data.Traversable --- Plurality monad: Zero, one, or at least two.+-- | Plurality monad: Zero, one, or at least two. data Plur a   = Zero-  | One a-  | Two a a+  | One !a+  | Two !a !a   deriving (Show, Eq, Ord)  instance Functor Plur where-  fmap f = \case+  fmap f plur = case plur of     Zero      -> Zero     One a     -> One (f a)     Two a1 a2 -> Two (f a1) (f a2)@@ -20,25 +22,26 @@ instance Applicative Plur where   pure = One -  (<*>) Zero _        = Zero-  (<*>) _ Zero        = Zero-  (<*>) (One f) x     = fmap f x-  (<*>) (Two f1 f2) x = fmap f1 x <> fmap f2 x+  Zero      <*> _    = Zero+  _         <*> Zero = Zero+  One f     <*> x    = fmap f x+  Two f1 f2 <*> x    = fmap f1 x `mappend` fmap f2 x  instance Monad Plur where-  (>>=) x f = case x of+  return = pure+  x >>= f = case x of     Zero      -> Zero     One x1    -> f x1-    Two x1 x2 -> f x1 <> f x2+    Two x1 x2 -> f x1 `mappend` f x2  instance Foldable Plur where-  foldMap f = \case+  foldMap f plur = case plur of     Zero      -> mempty     One a     -> f a-    Two a1 a2 -> f a1 <> f a2+    Two a1 a2 -> f a1 `mappend` f a2  instance Traversable Plur where-  traverse f = \case+  traverse f plur = case plur of     Zero      -> pure Zero     One a     -> One <$> f a     Two a1 a2 -> Two <$> f a1 <*> f a2@@ -48,14 +51,15 @@   Zero    <> r2      = r2   One x   <> One y   = Two x y   One x   <> Two y _ = Two x y-  Two x _ <> One y   = Two x y-  Two x _ <> Two y _ = Two x y+  Two x y <> _       = Two x y  instance Monoid (Plur a) where-  mempty = Zero+  mempty  = Zero+  mappend = (Semigroup.<>) +-- | Erase occurrences, resulting in @0@, @1@, or @2@. count :: Plur a -> Int-count = \case+count plur = case plur of   Zero    -> 0   One _   -> 1   Two _ _ -> 2

@@ -0,0 +1,31 @@+module Main (main) where++import Control.Applicative+import Data.Plur+import System.Exit+import qualified Hedgehog.Gen as Gen+import qualified Hedgehog.Range as Range++import Hedgehog+import Hedgehog.Classes++genPlur :: Gen x -> Gen (Plur x)+genPlur gen = Gen.choice+  [ pure Zero+  , One <$> gen+  , Two <$> gen <*> gen+  ]++main :: IO ()+main = do+  result <- lawsCheckMany+    [ ("Plur",+      [ functorLaws genPlur+      , applicativeLaws genPlur+      , monadLaws genPlur+      , traversableLaws genPlur+      , semigroupLaws $ genPlur Gen.unicode+      , monoidLaws $ genPlur Gen.unicode+      ])+    ]+  exitWith $ if result then ExitSuccess else ExitFailure 1