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{-# LANGUAGE FlexibleContexts #-} {-# OPTIONS_GHC -Wall #-} ------------------------------------------------------------------------------- {- | Module : Data.Env Description : Value environment. Copyright : (c) Paulo Silva License : LGPL Maintainer : paufil@di.uminho.pt Stability : experimental Portability : portable -} ------------------------------------------------------------------------------- module Data.Env ( Env, emptyEnv, fromListEnv, lookupEnv, addEnv, clearEnv, toList, indexes, values, delete, joinEnv ) where import Control.Monad.Error import Data.Map(Map) import qualified Data.Map as Map ------------------------------------------------------------------------------- type Env t = Map String t ------------------------------------------------------------------------------- emptyEnv :: Env t emptyEnv = Map.empty ------------------------------------------------------------------------------- fromListEnv :: [(String,t)] -> Env t fromListEnv = Map.fromList ------------------------------------------------------------------------------- lookupEnv :: MonadPlus m => String -> Env t -> m t lookupEnv n env = Map.lookup n env ------------------------------------------------------------------------------- addEnv :: String -> t -> Env t -> Env t addEnv k t = Map.insert k t ------------------------------------------------------------------------------- clearEnv :: Env t -> Env t clearEnv = const emptyEnv ------------------------------------------------------------------------------- toList :: Env t -> [(String,t)] toList = Map.toList ------------------------------------------------------------------------------- indexes :: Env t -> [String] indexes = Map.keys ------------------------------------------------------------------------------- values :: Env t -> [t] values = Map.elems ------------------------------------------------------------------------------- delete :: String -> Env t -> Env t delete = Map.delete ------------------------------------------------------------------------------- joinEnv :: Env t -> Env t -> Env t joinEnv = Map.union ------------------------------------------------------------------------------- |