unfoldable 0.0.0 → 0.1.0

raw patch · 3 files changed

+32/−4 lines, 3 filesdep ~transformers

Dependency ranges changed: transformers

Files

• src/Data/Splittable.hs +10/−2
• src/Data/Unfoldable.hs +20/−0
• unfoldable.cabal +2/−2

@@ -11,6 +11,7 @@  import qualified System.Random as R import Data.List (mapAccumR)+import Data.Monoid (Dual(..))  -- | Splittable datatypes are datatypes that can be used as seeds for unfolds. class Splittable s where@@ -24,10 +25,12 @@  -- | If a datatype is bounded and enumerable, we can use 'getInt' to produce a value from a seed. boundedEnum :: forall s a. (Splittable s, Bounded a, Enum a) => s -> a-boundedEnum s = toEnum $ (getInt s `mod` (1 + ub - lb)) + lb+boundedEnum s = toEnum $ (getInt s `mod'` (1 + ub - lb)) + lb   where      lb = fromEnum (minBound :: a)     ub = fromEnum (maxBound :: a)+    n `mod'` 0 = n - lb+    n `mod'` m = n `mod` m   data Left = L instance Splittable Left where@@ -39,7 +42,7 @@ instance Splittable Right where   split = replicate   choose fs = last fs-  getInt R = maxBound+  getInt R = 0  instance Splittable R.StdGen where   split 0 _ = []@@ -72,3 +75,8 @@   choose fs = either (choose (map (. Left) fs)) (choose (map (. Right) fs))   getInt (Left a) = getInt a * 2   getInt (Right a) = getInt a * 2 + 1++instance Splittable s => Splittable (Dual s) where+  split n = map Dual . reverse . split n . getDual+  choose fs = choose (map (. Dual) $ reverse fs) . getDual+  getInt = negate . getInt . getDual

@@ -16,6 +16,12 @@ import Control.Applicative import Control.Monad.Trans.State import Data.Splittable+import Data.Monoid (Dual(..))+import Data.Functor.Compose+import Data.Functor.Constant+import Data.Functor.Identity+import Data.Functor.Product+import Data.Functor.Reverse  -- | Data structures that can be unfolded. --@@ -76,3 +82,17 @@ instance (Bounded a, Enum a) => Unfoldable ((,) a) where   unfoldMap f = spread $ (,) <$> to boundedEnum <*> to f +instance Unfoldable Identity where+  unfoldMap f = Identity . f++instance (Bounded a, Enum a) => Unfoldable (Constant a) where+  unfoldMap _ = Constant . boundedEnum+  +instance (Unfoldable p, Unfoldable q) => Unfoldable (Product p q) where+  unfoldMap f = spread $ Pair <$> to (unfoldMap f) <*> to (unfoldMap f)++instance (Unfoldable p, Unfoldable q) => Unfoldable (Compose p q) where+  unfoldMap f = Compose . unfoldMap (unfoldMap f)++instance Unfoldable f => Unfoldable (Reverse f) where+  unfoldMap f = Reverse . unfoldMap (f . getDual) . Dual

@@ -1,5 +1,5 @@ Name:                unfoldable-Version:             0.0.0+Version:             0.1.0 Synopsis:            Class of data structures that can be unfolded from a seed value. Homepage:            https://github.com/sjoerdvisscher/unfoldable License:             BSD3@@ -19,7 +19,7 @@      Build-depends:       base         >= 4   && < 5 -    , transformers >= 0.2 && < 0.4+    , transformers >= 0.3 && < 0.4     , random       >= 1.0 && < 1.1  source-repository head