%
% (c) The University of Glasgow 2006
% (c) The AQUA Project, Glasgow University, 1994-1998
%
\section[UniqSet]{Specialised sets, for things with @Uniques@}

Based on @UniqFMs@ (as you would expect).

Basically, the things need to be in class @Uniquable@.

\begin{code}
module UniqSet (
        -- * Unique set type
        UniqSet,    -- abstract type: NOT

        -- ** Manipulating these sets
        mkUniqSet, uniqSetToList, emptyUniqSet, unitUniqSet,
        addOneToUniqSet, addListToUniqSet, addOneToUniqSet_C,
        delOneFromUniqSet, delListFromUniqSet, delOneFromUniqSet_Directly,
        unionUniqSets, unionManyUniqSets, minusUniqSet,
        elementOfUniqSet, mapUniqSet, intersectUniqSets,
        isEmptyUniqSet, filterUniqSet, sizeUniqSet, foldUniqSet,
        elemUniqSet_Directly, lookupUniqSet, hashUniqSet
    ) where

import Maybes
import UniqFM
import Unique

#if ! OMIT_NATIVE_CODEGEN
#define IF_NCG(a) a
#else
#define IF_NCG(a) {--}
#endif
\end{code}

%************************************************************************
%*                                                                      *
\subsection{The @UniqSet@ type}
%*                                                                      *
%************************************************************************

We use @UniqFM@, with a (@getUnique@-able) @Unique@ as ``key''
and the thing itself as the ``value'' (for later retrieval).

\begin{code}
--data UniqSet a = MkUniqSet (FiniteMap Unique a) : NOT

type UniqSet a = UniqFM a
#define MkUniqSet {--}

emptyUniqSet :: UniqSet a
emptyUniqSet = MkUniqSet emptyUFM

unitUniqSet :: Uniquable a => a -> UniqSet a
unitUniqSet x = MkUniqSet (unitUFM x x)

uniqSetToList :: UniqSet a -> [a]
uniqSetToList (MkUniqSet set) = eltsUFM set

foldUniqSet :: (a -> b -> b) -> b -> UniqSet a -> b
foldUniqSet k z (MkUniqSet set) = foldUFM k z set

mkUniqSet :: Uniquable a => [a]  -> UniqSet a
mkUniqSet xs = MkUniqSet (listToUFM [ (x, x) | x <- xs])

addOneToUniqSet :: Uniquable a => UniqSet a -> a -> UniqSet a
addOneToUniqSet (MkUniqSet set) x = MkUniqSet (addToUFM set x x)

addOneToUniqSet_C :: Uniquable a
                  => (a -> a -> a) -> UniqSet a -> a -> UniqSet a
addOneToUniqSet_C f (MkUniqSet set) x = MkUniqSet (addToUFM_C f set x x)

delOneFromUniqSet :: Uniquable a => UniqSet a -> a -> UniqSet a
delOneFromUniqSet (MkUniqSet set) x = MkUniqSet (delFromUFM set x)

delOneFromUniqSet_Directly :: Uniquable a => UniqSet a -> Unique -> UniqSet a
delOneFromUniqSet_Directly (MkUniqSet set) u
    = MkUniqSet (delFromUFM_Directly set u)

delListFromUniqSet :: Uniquable a => UniqSet a -> [a] -> UniqSet a
delListFromUniqSet (MkUniqSet set) xs = MkUniqSet (delListFromUFM set xs)

addListToUniqSet :: Uniquable a => UniqSet a -> [a] -> UniqSet a
addListToUniqSet (MkUniqSet set) xs = MkUniqSet (addListToUFM set [(x,x) | x<-xs])

unionUniqSets :: UniqSet a -> UniqSet a -> UniqSet a
unionUniqSets (MkUniqSet set1) (MkUniqSet set2) = MkUniqSet (plusUFM set1 set2)

unionManyUniqSets :: [UniqSet a] -> UniqSet a
-- = foldr unionUniqSets emptyUniqSet ss
unionManyUniqSets []     = emptyUniqSet
unionManyUniqSets [s]    = s
unionManyUniqSets (s:ss) = s `unionUniqSets` unionManyUniqSets ss

minusUniqSet  :: UniqSet a -> UniqSet a -> UniqSet a
minusUniqSet (MkUniqSet set1) (MkUniqSet set2) = MkUniqSet (minusUFM set1 set2)

filterUniqSet :: (a -> Bool) -> UniqSet a -> UniqSet a
filterUniqSet pred (MkUniqSet set) = MkUniqSet (filterUFM pred set)

intersectUniqSets :: UniqSet a -> UniqSet a -> UniqSet a
intersectUniqSets (MkUniqSet set1) (MkUniqSet set2) = MkUniqSet (intersectUFM set1 set2)

elementOfUniqSet :: Uniquable a => a -> UniqSet a -> Bool
elementOfUniqSet x (MkUniqSet set) = maybeToBool (lookupUFM set x)

lookupUniqSet :: Uniquable a => UniqSet a -> a -> Maybe a
lookupUniqSet (MkUniqSet set) x = lookupUFM set x

elemUniqSet_Directly :: Unique -> UniqSet a -> Bool
elemUniqSet_Directly x (MkUniqSet set) = maybeToBool (lookupUFM_Directly set x)

sizeUniqSet :: UniqSet a -> Int
sizeUniqSet (MkUniqSet set) = sizeUFM set

hashUniqSet :: UniqSet a -> Int
hashUniqSet (MkUniqSet set) = hashUFM set

isEmptyUniqSet :: UniqSet a -> Bool
isEmptyUniqSet (MkUniqSet set) = isNullUFM set {-SLOW: sizeUFM set == 0-}

-- | Invariant: the mapping function doesn't change the unique
mapUniqSet :: (a -> a) -> UniqSet a -> UniqSet a
mapUniqSet f (MkUniqSet set) = MkUniqSet (mapUFM f set)
\end{code}

\begin{code}
#ifdef __GLASGOW_HASKELL__
{-# SPECIALIZE
    addOneToUniqSet :: UniqSet Unique -> Unique -> UniqSet Unique
    #-}

-- These next three specialisations disabled as importing Name creates a
-- loop, and getting the Uniquable Name instance in particular is tricky.

{- SPECIALIZE
    elementOfUniqSet :: Name -> UniqSet Name -> Bool
                      , Unique -> UniqSet Unique -> Bool
    -}
{- SPECIALIZE
    mkUniqSet :: [Name] -> UniqSet Name
    -}

{- SPECIALIZE
    unitUniqSet :: Name -> UniqSet Name
                 , Unique -> UniqSet Unique
    -}
#endif
\end{code}