protolude-0.1.5: src/Semiring.hs

{-# LANGUAGE Safe #-}
{-# LANGUAGE NoImplicitPrelude #-}

module Semiring (
  Semiring(..),
  zero,
) where

import Data.Monoid

-- | Alias for 'mempty'
zero :: Monoid m => m
zero = mempty

class Monoid m => Semiring m where
  {-# MINIMAL one, (<.>) #-}

  one :: m
  (<.>) :: m -> m -> m