--
-- $Header: /Users/dap/lua/RCS/Hanoi.lua,v 1.5 2007/02/11 08:49:51 dap Exp $
--
-- Hanoi - Towers of Hanoi diversion
--
-- Author (a) 2007, Damon A Permezel.  All bugs revered.
--
module(..., package.seeall)

OO=require"OO"

local Hanoi = OO.class {
   __name = "Hanoi base class",
   MAX_RINGS = 9,
   nRings = 3,
}

--
-- init - initialise a Hanoi object instance
--
function Hanoi:init()
   if 0 >= self.nRings or self.nRings > Hanoi.MAX_RINGS then
      error(('funny number of rings: %d'):format(self.nRings))
   end
end

--
-- run - perform the Towers of Hanoi algorithm
--

function Hanoi:run()
   self:hanoi(self:reset())
end

--
-- hanoi - the guts of the algorithm
--
-- Input:
--	n	# of rings
--	from	pole to move from
--	to	pole to move to
--	work	pole to aid in performing work
--
function Hanoi:hanoi(n, from, to, work)

   if n > 0 and not self.stop then
      self:hanoi(n-1, from, work, to)
      self:moveRing(n, from, to)
      self:hanoi(n-1, work, to, from)
   end
end

--
-- moveRing - default method to move ring
--
-- Override this with something more interesting!
--
function Hanoi:moveRing(n, from, to)
   print(("move ring %3d from %8s to %8s"):format(n, from, to))
end

--
-- reset - default reset method
--
-- Override this with what your moveRing needs....
--
function Hanoi:reset()
   return self.nRings, 'A', 'B', 'C'
end

return Hanoi