lookup -containers

lookup :: Eq a => a -> [(a, b)] -> Maybe b
base Prelude, base Data.List
lookup key assocs looks up a key in an association list.
lookup :: HashTable key val -> key -> IO (Maybe val)
base Data.HashTable
Looks up the value of a key in the hash table.
lookupFM :: Ord a => FiniteMap a b -> a -> Maybe b
fgl Data.Graph.Inductive.Internal.FiniteMap
lookupHeader :: HeaderName -> [Header] -> Maybe String
HTTP Network.HTTP.Headers
lookupHeader hdr hdrs locates the first header matching hdr in the list hdrs.
lookupName :: Bool -> String -> Q (Maybe Name)
template-haskell Language.Haskell.TH.Syntax
lookupTypeName :: String -> Q (Maybe Name)
template-haskell Language.Haskell.TH.Syntax, template-haskell Language.Haskell.TH
Look up the given name in the (type namespace of the) current splice's scope. See Language.Haskell.TH.Syntax#namelookup for more details.
lookupValueName :: String -> Q (Maybe Name)
template-haskell Language.Haskell.TH.Syntax, template-haskell Language.Haskell.TH
Look up the given name in the (value namespace of the) current splice's scope. See Language.Haskell.TH.Syntax#namelookup for more details.
qLookupName :: Quasi m => Bool -> String -> m (Maybe Name)
template-haskell Language.Haskell.TH.Syntax