{-# LANGUAGE TypeFamilies #-}

{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE DataKinds #-}

-- |

-- Module      : OAlg.Data.Relation

-- Description : binary relations.

-- Copyright   : (c) Erich Gut

-- License     : BSD3

-- Maintainer  : zerich.gut@gmail.com

-- 

-- binary relations.

module OAlg.Data.Relation
  ( -- * Symmetric

    Symmetric(..)
  )
  where

--------------------------------------------------------------------------------

-- Symmetric -


-- | symmetric relation.

class Symmetric r where
  swap :: r x y -> r y x