{- |

Module : $Header$

Copyright : (c) Klaus L�ttich, Uni Bremen 2002-2004

License : similar to LGPL, see HetCATS/LICENSE.txt or LIZENZ.txt

Maintainer : maeder@tzi.de

Stability : provisional

Portability : portable

-}

module Common.ATerm.AbstractSyntax

(ShATerm(..),

ATermTable,

emptyATermTable,

addATerm,addATermNoFullSharing,

getATerm,

getATermIndex,getTopIndex,

getATermByIndex1) where

import qualified Common.Lib.Map as Map

import qualified Common.Lib.Map as DMap

data ShATerm = ShAAppl String [Int] [Int]

| ShAList [Int] [Int]

| ShAInt Integer [Int]

deriving (Eq,Ord)

data ATermTable = ATT !(Map.Map ShATerm Int) !(DMap.Map Int ShATerm) Int

emptyATermTable :: ATermTable

emptyATermTable = ATT Map.empty DMap.empty (-1)

addATermNoFullSharing :: ShATerm -> ATermTable -> (ATermTable,Int)

addATermNoFullSharing t (ATT a_iDFM i_aDFM i1) = let j = i1 + 1 in

(ATT (Map.insert t j a_iDFM) (DMap.insert j t i_aDFM) j, j)

addATerm :: ShATerm -> ATermTable -> (ATermTable,Int)

addATerm t at@(ATT a_iDFM _ _) =

case Map.lookup t a_iDFM of

Nothing -> addATermNoFullSharing t at

Just i -> (at, i)

getATerm :: ATermTable -> ShATerm

getATerm (ATT _ i_aFM i) =

DMap.findWithDefault (ShAInt (-1) []) i i_aFM

getTopIndex :: ATermTable -> Int

getTopIndex (ATT _ _ i) = i

getATermIndex :: ShATerm -> ATermTable -> Int

getATermIndex t (ATT a_iDFM _ _) = Map.findWithDefault (-1) t a_iDFM

getATermByIndex1 :: Int -> ATermTable -> ATermTable

getATermByIndex1 i (ATT a_iDFM i_aDFM _) = ATT a_iDFM i_aDFM i