{- |

Module : $Header$

Description : Accessing the Labels of Maude data types

Copyright : (c) Martin Kuehl, Uni Bremen 2008-2009

License : GPLv2 or higher, see LICENSE.txt

Maintainer : mkhl@informatik.uni-bremen.de

Stability : experimental

Portability : portable

Accessing the Labels of Maude data types.

Defines a type class 'HasLabels' that lets us access the 'Label's of

Maude data types as 'SymbolSet's.

Consider importing "Maude.Meta" instead of this module.

-}

module Maude.Meta.HasLabels (

-- * The HasLabels type class

HasLabels(..)

) where

import Maude.AS_Maude

import Maude.Symbol

import Maude.Meta.AsSymbol

import Maude.Meta.HasName

import Data.Set (Set)

import qualified Data.Set as Set

-- * The HasLabels type class

-- | Represents something that contains a 'Set' of 'Label's (as 'Symbol's).

class HasLabels a where

-- | Extract the 'Label's contained in the input.

getLabels :: a -> SymbolSet

-- | Map the 'Label's contained in the input.

mapLabels :: SymbolMap -> a -> a

-- * Predefined instances

instance (HasLabels a) => HasLabels [a] where

getLabels = Set.unions . map getLabels

mapLabels = map . mapLabels

instance (HasLabels a, HasLabels b) => HasLabels (a, b) where

getLabels (a, b) = Set.union (getLabels a) (getLabels b)

mapLabels mp (a, b) = (mapLabels mp a, mapLabels mp b)

instance (HasLabels a, HasLabels b, HasLabels c) => HasLabels (a, b, c) where

getLabels (a, b, c) = Set.union (getLabels a) (getLabels (b, c))

mapLabels mp (a, b, c) = (mapLabels mp a, mapLabels mp b, mapLabels mp c)

instance (Ord a, HasLabels a) => HasLabels (Set a) where

getLabels = Set.fold (Set.union . getLabels) Set.empty

mapLabels = Set.map . mapLabels

instance HasLabels StmntAttr where

getLabels = asSymbolSet

mapLabels = mapAsSymbol $ Label . getName

instance HasLabels Membership where

getLabels (Mb _ _ _ as) = getLabels as

mapLabels mp (Mb ts ss cs as) = Mb ts ss cs (mapLabels mp as)

instance HasLabels Equation where

getLabels (Eq _ _ _ as) = getLabels as

mapLabels mp (Eq t1 t2 cs as) = Eq t1 t2 cs (mapLabels mp as)

instance HasLabels Rule where

getLabels (Rl _ _ _ as) = getLabels as

mapLabels mp (Rl t1 t2 cs as) = Rl t1 t2 cs (mapLabels mp as)