{- |

Module : $Header$

Description : description of undo and redo functions

Copyright : uni-bremen and DFKI

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

Maintainer : r.pascanu@jacobs-university.de

Stability : provisional

Portability : portable

PGIP.UnDoRedo contains the implementation of the undo and redo commads

-}

module PGIP.UndoRedo

( cUndo

, cRedo

) where

import Interfaces.DataTypes

import Interfaces.History

import PGIP.DataTypes

import PGIP.DataTypesUtils

import System.IO

import Data.List

-- | Undoes the last command entered

cUndo :: CMDL_State -> IO CMDL_State

cUndo state =

case undoList $ i_hist $ intState state of

[] -> return $ genMessage [] "Nothing to undo" state

action:_ -> return $ genMessage [] ("Action '"++(cmdName action)

++ "' is now undone") $

state {

intState = undoOneStep $ intState state }

-- | Redoes the last undo command

cRedo :: CMDL_State -> IO CMDL_State

cRedo state =

case redoList $ i_hist $ intState state of

[] -> return $ genMessage [] "Nothing to redo" state

action:_ -> return $ genMessage [] ("Action '"++(cmdName action)

++ "' is now redone") $

state {

intState = redoOneStep $ intState state }