module Language.Core.Env (Env,
eempty,
elookup,
eextend,
edomain,
efromlist,
etolist,
efilter,
eremove)
where
import qualified Data.Map as M
data Env a b = Env (M.Map a b)
deriving Show
eempty :: Env a b
eempty = Env M.empty
elookup :: (Eq a, Ord a) => Env a b -> a -> Maybe b
elookup (Env l) k = M.lookup k l
eextend :: Ord a => Env a b -> (a,b) -> Env a b
eextend (Env l) (k,d) = Env (M.insert k d l)
edomain :: (Eq a) => Env a b -> [a]
edomain (Env l) = M.keys l
efromlist :: Ord a => [(a,b)] -> Env a b
efromlist = Env . M.fromList
etolist :: Env a b -> [(a,b)]
etolist (Env l) = M.toList l
eremove :: (Eq a, Ord a) => Env a b -> a -> Env a b
eremove (Env l) k = Env (M.delete k l)
efilter :: Ord a => Env a b -> (a -> Bool) -> Env a b
efilter (Env l) p = Env (M.filterWithKey (\ k _ -> p k) l)