commutative-semigroups 0.0.2.0 → 0.1.0.0

raw patch · 4 files changed

+129/−2 lines, 4 filesdep ~basePVP ok

version bump matches the API change (PVP)

Dependency ranges changed: base

API changes (from Hackage documentation)

Files

• ChangeLog.md +21/−0
• commutative-semigroups.cabal +2/−1
• src/Data/Semigroup/Commutative.hs +2/−1
• src/Numeric/Product/Commutative.hs +104/−0

@@ -1,5 +1,26 @@ # Revision history for commutative-semigroups +## 0.1.0.0 -- 2022-06-12++- `Commutative (Product a)` now requires `CommutativeProduct a`.+  `CommutativeProduct` is a new class to indicate `(*)` from `Num` is+  commutative, which is not required by `Num`. (Example:+  multiplication on+  [quaternions](https://en.wikipedia.org/wiki/Quaternion) is+  non-commutative, and the `Quaternion a` type from the `linear`+  package has a valid `instance RealFloat a => Num (Quaternion a)`.)++  **Remark:** There is also no canonical subclass class in the `Num`+  hierarchy which implies commutative `(*)`, as both `Integral` and+  `Floating` instances work here:++  - `Integral` instances are customarily Euclidean Domains, which are+    commutative rings with extra conditions.++  - `Floating` instances customarily expect `(+)`, `(*)`, and `exp` to+    form an exponential field, which is also a commutative ring with+    extra conditions.+ ## 0.0.2.0 -- 2022-03-26  - Add `instance Ord a => Commutative (Set a)`

@@ -1,6 +1,6 @@ cabal-version:       2.4 name:                commutative-semigroups-version:             0.0.2.0+version:             0.1.0.0 synopsis:            Commutative semigroups description:   A commutative semigroup is a semigroup where the order of arguments to mappend does not matter.@@ -22,6 +22,7 @@  library   exposed-modules:     Data.Semigroup.Commutative+                       Numeric.Product.Commutative   -- other-modules:   build-depends:       base >= 4.6 && < 4.17,                        containers >= 0.4 && < 0.7

@@ -24,6 +24,7 @@ import Data.Functor.Contravariant (Op(Op)) import GHC.Generics #endif+import Numeric.Product.Commutative ( CommutativeProduct )  -- |An 'Commutative' semigroup is a 'Semigroup' that follows the rule: --@@ -44,7 +45,7 @@  instance Num a => Commutative (Sum a) -instance Fractional a => Commutative (Product a)+instance CommutativeProduct a => Commutative (Product a)  instance Commutative a => Commutative (Dual a) 

@@ -0,0 +1,104 @@+{-# LANGUAGE CPP #-}+module Numeric.Product.Commutative+  ( CommutativeProduct (..)+  )+  where++import Control.Applicative (Const)+import Data.Complex (Complex)+import Data.Fixed+import Data.Functor.Identity+import Data.Int+import Data.Ratio (Ratio)+import Data.Word+import Numeric.Natural++#if MIN_VERSION_base(4, 9, 0)+import Data.Semigroup (Max, Min, Product, Sum)+#endif++#if MIN_VERSION_base(4, 11, 0)+import Data.Ord (Down)+#endif++#if MIN_VERSION_base(4, 12, 0)+import Data.Functor.Contravariant (Op)+import Data.Monoid (Alt)+#endif++-- | Subclass of 'Num' where '(*)' is commutative.+--+-- 'Num' doesn't demand commutative '(*)', and there are reasonable+-- "real-world" instances with non-commutative multiplication. There+-- is also no canonical subclass in @base@ that would suffice, as both+-- 'Integral' and 'Floating' imply commutative '(*)' for different+-- reasons.+--+-- Two examples of non-commutative '(*)':+--+-- * @Linear.Quaternion.Quaterion@ from the @linear@ package has a+--   'Num' instance, and quaternion multiplication is+--   noncommutative.+--+-- * @Data.Matrix.Matrix@ from the @matrix@ package uses '(*)' for+--   matrix multiplication, which is also non-commutative (on square+--   matrices, which is the only time the question makes sense).+--+-- @since 0.1.0+class Num a => CommutativeProduct a++instance CommutativeProduct Int8+instance CommutativeProduct Int16+instance CommutativeProduct Int32+instance CommutativeProduct Int64+instance CommutativeProduct Int+instance CommutativeProduct Integer++instance CommutativeProduct Word8+instance CommutativeProduct Word16+instance CommutativeProduct Word32+instance CommutativeProduct Word64+instance CommutativeProduct Word+instance CommutativeProduct Natural++instance CommutativeProduct Float+instance CommutativeProduct Double++instance (RealFloat a, CommutativeProduct a) => CommutativeProduct (Complex a)++instance CommutativeProduct a => CommutativeProduct (Identity a)++-- @since: base-4.7.0.0+instance CommutativeProduct a => CommutativeProduct (Sum a)++-- @since: base-4.7.0.0+instance (Integral a, CommutativeProduct a) => CommutativeProduct (Ratio a)++instance (HasResolution a, CommutativeProduct a) => CommutativeProduct (Fixed a)++#if MIN_VERSION_base(4, 9, 0)+-- @since: base-4.9.0.0+instance CommutativeProduct a => CommutativeProduct (Min a)++-- @since: base-4.9.0.0+instance CommutativeProduct a => CommutativeProduct (Max a)++-- @since: base-4.9.0.0+instance CommutativeProduct a => CommutativeProduct (Product a)++-- @since: base-4.9.0.0+instance CommutativeProduct a => CommutativeProduct (Const a b)+#endif++#if MIN_VERSION_base(4, 11, 0)+-- @since: base-4.11.0.0+instance CommutativeProduct a => CommutativeProduct (Down a)+#endif++#if MIN_VERSION_base(4, 12, 0)+-- @since: base-4.12.0.0+instance CommutativeProduct a => CommutativeProduct (Op a b)++-- @since: base-4.12.0.0+instance CommutativeProduct (f a) => CommutativeProduct (Alt f a)+#endif