Navigator.hs

-----------------------------------------------------------------------------
-- |
-- Module      :  Control.Search.Local.Navigator
-- Copyright   :  (c) Richard Senington & David Duke 2010
-- License     :  GPL-style
-- 
-- Maintainer  :  Richard Senington <sc06r2s@leeds.ac.uk>
-- Stability   :  provisional
-- Portability :  portable
-- 
-- The two ways to navigate a tree. The paper reduced all the different local search strategies to transformations 
-- composed with a first choice system, so that is the navigator that is expected to be used. However we also 
-- provide a manual inspection navigator, that allows for human interaction, by typing the number of the node 
-- you wish to move to.
----------------------------------------------------------------------------- 

module Control.Search.Local.Navigator (
  firstChoice,
  manualNavigator
)where

import Control.Search.Local.Tree
import Control.Search.Local.Transformation
import Control.Search.Local.Neighbourhood

firstChoice :: LSTree a->[a]
firstChoice t | (null.treeNodeChildren) t = [treeNodeName t]
              | otherwise = treeNodeName t : (firstChoice (head (treeNodeChildren t)))     

-- | Types left out of the next two parts because of compilation problems with type inference if included.
manualNavigator t = 
  do displayLSSpace t
     putStr ": "
     x<-getLine
     if x=="q" then return ()
               else do let i = (read x)::Int
                       manualNavigator (treeNodeChildren t !! i)

displayLSSpace t = 
  do let nme = treeNodeName t
     putStrLn $ "Current Location : "++(show nme)
     putStrLn $ "  Current Price : " -- ++(show $ priceSolution nme)
     putStrLn $ "  Neighbourhood"
     mapM_ putStrLn $ map (\(x,y)->"    "++(show x)++" "++(show.treeNodeName $  y)++" "++(show.priceSolution.treeNodeName $  y)) (zip [0..] $ treeNodeChildren t)