    {-# LANGUAGE CPP, TypeFamilies #-}
    #if __GLASGOW_HASKELL__ >= 701
    {-# LANGUAGE Safe #-}
    #endif

    module Compiler.Hoopl.Label
      ( Label
      , freshLabel
      , LabelSet, LabelMap
      , FactBase, noFacts, lookupFact

      , uniqueToLbl -- MkGraph and GHC use only
      , lblToUnique -- GHC use only
      )

    where

    import Compiler.Hoopl.Collections
    import Compiler.Hoopl.Unique

    -----------------------------------------------------------------------------
    --		Label
    -----------------------------------------------------------------------------

    newtype Label = Label { lblToUnique :: Unique }
      deriving (Eq, Ord)

    uniqueToLbl :: Unique -> Label
    uniqueToLbl = Label

    instance Show Label where
      show (Label n) = "L" ++ show n

    freshLabel :: UniqueMonad m => m Label
    freshLabel = freshUnique >>= return . uniqueToLbl

    -----------------------------------------------------------------------------
    -- LabelSet

    newtype LabelSet = LS UniqueSet deriving (Eq, Ord, Show)

    instance IsSet LabelSet where
      type ElemOf LabelSet = Label

      setNull (LS s) = setNull s
      setSize (LS s) = setSize s
      setMember (Label k) (LS s) = setMember k s

      setEmpty = LS setEmpty
      setSingleton (Label k) = LS (setSingleton k)
      setInsert (Label k) (LS s) = LS (setInsert k s)
      setDelete (Label k) (LS s) = LS (setDelete k s)

      setUnion (LS x) (LS y) = LS (setUnion x y)
      setDifference (LS x) (LS y) = LS (setDifference x y)
      setIntersection (LS x) (LS y) = LS (setIntersection x y)
      setIsSubsetOf (LS x) (LS y) = setIsSubsetOf x y

      setFold k z (LS s) = setFold (k . uniqueToLbl) z s

      setElems (LS s) = map uniqueToLbl (setElems s)
      setFromList ks = LS (setFromList (map lblToUnique ks))

    -----------------------------------------------------------------------------
    -- LabelMap

    newtype LabelMap v = LM (UniqueMap v) deriving (Eq, Ord, Show)

    instance IsMap LabelMap where
      type KeyOf LabelMap = Label

      mapNull (LM m) = mapNull m
      mapSize (LM m) = mapSize m
      mapMember (Label k) (LM m) = mapMember k m
      mapLookup (Label k) (LM m) = mapLookup k m
      mapFindWithDefault def (Label k) (LM m) = mapFindWithDefault def k m

      mapEmpty = LM mapEmpty
      mapSingleton (Label k) v = LM (mapSingleton k v)
      mapInsert (Label k) v (LM m) = LM (mapInsert k v m)
      mapInsertWith f (Label k) v (LM m) = LM (mapInsertWith f k v m)
      mapDelete (Label k) (LM m) = LM (mapDelete k m)

      mapUnion (LM x) (LM y) = LM (mapUnion x y)
      mapUnionWithKey f (LM x) (LM y) = LM (mapUnionWithKey (f . uniqueToLbl) x y)
      mapDifference (LM x) (LM y) = LM (mapDifference x y)
      mapIntersection (LM x) (LM y) = LM (mapIntersection x y)
      mapIsSubmapOf (LM x) (LM y) = mapIsSubmapOf x y

      mapMap f (LM m) = LM (mapMap f m)
      mapMapWithKey f (LM m) = LM (mapMapWithKey (f . uniqueToLbl) m)
      mapFold k z (LM m) = mapFold k z m
      mapFoldWithKey k z (LM m) = mapFoldWithKey (k . uniqueToLbl) z m
      mapFilter f (LM m) = LM (mapFilter f m)

      mapElems (LM m) = mapElems m
      mapKeys (LM m) = map uniqueToLbl (mapKeys m)
      mapToList (LM m) = [(uniqueToLbl k, v) | (k, v) <- mapToList m]
      mapFromList assocs = LM (mapFromList [(lblToUnique k, v) | (k, v) <- assocs])
      mapFromListWith f assocs = LM (mapFromListWith f [(lblToUnique k, v) | (k, v) <- assocs])

    -----------------------------------------------------------------------------
    -- FactBase

    type FactBase f = LabelMap f

    noFacts :: FactBase f
    noFacts = mapEmpty

    lookupFact :: Label -> FactBase f -> Maybe f
    lookupFact = mapLookup