{-# LANGUAGE
  FlexibleContexts,
  FlexibleInstances,
  TypeFamilies
  #-}
module Data.HList.Graph
    ( HNodeSet
    , HNode(..)
    , HGraph(..)
    )
    where

import Data.HList.Prelude

-- HNodeSet
class    HNodeSet ns
instance HNodeSet HNil
instance HNodeSet ns => HNodeSet (HCons n ns)

-- HNode
class ( HNodeSet (HLinksFrom n)
      )
    => HNode n
    where
      type HNodeID n
      type HLinksFrom n

-- HGraph
class ( HNodeSet (HNodes g)
      )
    => HGraph g
    where
      type HNodes g