{-# LANGUAGE DeriveDataTypeable #-}

{- |

Module : ./Common/ProofTree.hs

Description : a simple proof tree

Copyright : (c) DFKI GmbH, Uni Bremen 2002-2008

License : GPLv2 or higher, see LICENSE.txt

Maintainer : Christian.Maeder@dfki.de

Stability : provisional

Portability : portable

Datatype for storing of the proof tree

-}

module Common.ProofTree where

import Data.Data

{- |

Datatype for storing of the proof tree. The Show class is instantiated.

-}

data ProofTree = ProofTree String deriving (Eq, Ord, Typeable, Data)

instance Show ProofTree where

show (ProofTree st) = st

emptyProofTree :: ProofTree

emptyProofTree = ProofTree ""