semiring-num 0.5.2.0 → 0.5.3.0

raw patch · 2 files changed

+28/−9 lines, 2 files

Files

• semiring-num.cabal +1/−1
• src/Data/Semiring.hs +27/−8

@@ -1,5 +1,5 @@ name:                semiring-num-version:             0.5.2.0+version:             0.5.3.0 synopsis:            Basic semiring class and instances description:         Adds a basic semiring class homepage:            https://github.com/oisdk/semiring-num

@@ -234,11 +234,27 @@  -- | Takes the sum of the elements of a 'Foldable'. Analogous to 'sum' -- on numbers, or 'or' on 'Bool's.+-- >>> add [1..5]+-- 15+-- >>> add [False, False]+-- False+-- >>> add [False, True]+-- True+-- >>> add [True, undefined]+-- True add :: (Foldable f, Semiring a) => f a -> a add = getAdd . foldMap Add  -- | Takes the product of the elements of a 'Foldable'. Analogous to -- 'product' on numbers, or 'and' on 'Bool's.+-- >>> mul [1..5]+-- 120+-- >>> mul [True, True]+-- True+-- >>> mul [True, False]+-- False+-- >>> mul [False, undefined]+-- False mul :: (Foldable f, Semiring a) => f a -> a mul = getMul . foldMap Mul @@ -246,21 +262,20 @@ -- Ord wrappers ------------------------------------------------------------------------ - -- | The "<https://ncatlab.org/nlab/show/tropical+semiring Tropical>" or -- min-plus semiring. It is a semiring where: -- -- @'<+>'  = 'min'---'zero' = -∞ -- represented by 'Nothing'+--'zero' = ∞ -- represented by 'Nothing' --'<.>'  = '<+>' --'one'  = 'zero'@ -- -- Note that we can't use 'Data.Semigroup.Min' from 'Data.Semigroup' -- because annihilation needs to hold: ----- @-∞ '<+>' x = x '<+>' -∞ = -∞@+-- @∞ '<+>' x = x '<+>' ∞ = ∞@ ----- Taking -∞ to be 'minBound' would break the above law. Using 'Nothing'+-- Taking ∞ to be 'maxBound' would break the above law. Using 'Nothing' -- to represent it follows the law. newtype Min a = Min   { getMin :: Maybe a@@ -271,16 +286,16 @@ -- or max-plus semiring. It is a semiring where: -- -- @'<+>'  = 'max'---'zero' = ∞ -- represented by 'Nothing'+--'zero' = -∞ -- represented by 'Nothing' --'<.>'  = '<+>' --'one'  = 'zero'@ -- -- Note that we can't use 'Data.Semigroup.Max' from 'Data.Semigroup' -- because annihilation needs to hold: ----- @∞ '<+>' x = x '<+>' ∞ = ∞@+-- @-∞ '<+>' x = x '<+>' -∞ = -∞@ ----- Taking ∞ to be 'maxBound' would break the above law. Using 'Nothing'+-- Taking -∞ to be 'minBound' would break the above law. Using 'Nothing' -- to represent it follows the law. newtype Max a = Max   { getMax :: Maybe a@@ -312,17 +327,21 @@ instance Ord a => Semigroup (Max a) where   Max Nothing <> x = x   x <> Max Nothing = x-  Max (Just x) <> Max (Just y) = (Max . Just) (min x y)+  Max (Just x) <> Max (Just y) = (Max . Just) (max x y)  instance Ord a => Semigroup (Min a) where   Min Nothing <> x = x   x <> Min Nothing = x   Min (Just x) <> Min (Just y) = (Min . Just) (min x y) +-- | >>> (getMax . foldMap pure) [1..10]+-- Just 10 instance Ord a => Monoid (Max a) where   mempty = Max Nothing   mappend = (<>) +-- | >>> (getMin . foldMap pure) [1..10]+-- Just 1 instance Ord a => Monoid (Min a) where   mempty = Min Nothing   mappend = (<>)