- | An empty node.
newNode :: k -> cls -> Node k cls color
newNode k cls
        = Node
        { nodeId                = k
        , nodeClass             = cls
        , nodeColor             = Nothing
        , nodeConflicts         = emptyUniqSet
        , nodeExclusions        = emptyUniqSet
        , nodePreference        = []
        , nodeCoalesce          = emptyUniqSet }

newNode :: k -> cls -> Node k cls color
newNode k cls
        = Node
        { nodeId                = k
        , nodeClass             = cls
        , nodeColor             = Nothing
        , nodeConflicts         = emptyUniqSet
        , nodeExclusions        = emptyUniqSet
        , nodePreference        = []
        , nodeCoalesce          = emptyUniqSet }
newNode k cls
        = Node
        { nodeId                = k
        , nodeClass             = cls
        , nodeColor             = Nothing
        , nodeConflicts         = emptyUniqSet
        , nodeExclusions        = emptyUniqSet
        , nodePreference        = []
        , nodeCoalesce          = emptyUniqSet }