validity-containers-0.2.0.0: src/Data/Validity/Map.hs

{-# OPTIONS_GHC -fno-warn-orphans #-}

module Data.Validity.Map where

import Data.Validity

import Data.Map (Map)
import qualified Data.Map as M

-- | A 'Map' of things is valid if all the keys and values are valid and the 'Map' itself
-- is valid.
instance (Ord k, Validity k, Validity v) => Validity (Map k v) where
    isValid m = M.valid m && all isValid (M.toList m)
    validate m =
        mconcat
            [ M.valid m <?@> "The Map structure is valid."
            , M.toList m <?!> "Map elements"
            ]