import Char  -- comment out if your Hugs fusses about this line
import Turing

-- swop 'a's and 'b's in the input string
convertAB :: Prog
convertAB = [(("scan",'a'),('b',Rght,"scan")),
	     (("scan",'b'),('a',Rght,"scan"))]
            
-- add one to the binary number in the input
increment :: Prog 
increment = [(("scanRght",'0'),('0',Rght,"scanRght")),
	     (("scanRght",'1'),('1',Rght,"scanRght")),
	     (("scanRght",' '),(' ',Lft,"carry")),
	     (("carry",'1'),('0',Lft,"carry")),
	     (("carry",' '),('1',Lft,"finishUp")),
	     (("carry",'0'),('1',Lft,"finishUp")),
	     (("finishUp",'0'),('0',Lft,"finishUp")),
	     (("finishUp",'1'),('1',Lft,"finishUp"))
            ]

-- Decide if the input is == 0 (mod 3)
mod3 :: Prog
mod3 = [(("mod0",' '),('Y',Lft,"done")),
	(("mod0",'0'),(' ',Rght,"mod0")),
	(("mod0",'1'),(' ',Rght,"mod1")),
	(("mod1",' '),('N',Lft,"done")),
	(("mod1",'0'),(' ',Rght,"mod2")),
	(("mod1",'1'),(' ',Rght,"mod0")),
	(("mod2",' '),('N',Lft,"done")),
	(("mod2",'0'),(' ',Rght,"mod1")),
	(("mod2",'1'),(' ',Rght,"mod2"))
       ]

-- make a copy of the input 
copy :: Prog
copy =  [(("read",' '),(' ',Lft,"done")),
	 (("read",'a'),('A',Rght,"skipA")),
	 (("read",'b'),('B',Rght,"skipB")),
	 (("skipA",'a'),('a',Rght,"skipA")),
 	 (("skipA",'b'),('b',Rght,"skipA")),
	 (("skipA",' '),(' ',Rght,"copyA")),
	 (("copyA",'a'),('a',Rght,"copyA")),
	 (("copyA",'b'),('b',Rght,"copyA")),
	 (("copyA",' '),('a',Lft,"getNext")),
	 (("skipB",'a'),('a',Rght,"skipB")),
	 (("skipB",'b'),('b',Rght,"skipB")),
	 (("skipB",' '),(' ',Rght,"copyB")),
	 (("copyB",'a'),('a',Rght,"copyB")),
	 (("copyB",'b'),('b',Rght,"copyB")),
	 (("copyB",' '),('b',Lft,"getNext")),
	 (("getNext",'a'),('a',Lft,"getNext")),
	 (("getNext",'b'),('b',Lft,"getNext")),
	 (("getNext",' '),(' ',Lft,"getNext2")),
	 (("getNext2",'a'),('a',Lft,"getNext2")),
	 (("getNext2",'b'),('b',Lft,"getNext2")),
	 (("getNext2",'A'),('a',Rght,"read")),
	 (("getNext2",'B'),('b',Rght,"read")),
	 (("done",'a'),('a',Lft,"done")),
	 (("done",'b'),('b',Lft,"done"))
        ]

-- reverse the input string
reverseTM :: Prog
reverseTM = [(("readL",'a'),('A',Rght,"copyAL")),
	     (("readL",'b'),('B',Rght,"copyBL")),
	     (("readL",'A'),('a',Lft,"finish")),
	     (("readL",'B'),('b',Lft,"finish")),
	     (("copyAL",'a'),('a',Rght,"copyAL")),
	     (("copyAL",'b'),('b',Rght,"copyAL")),
	     (("copyAL",' '),(' ',Lft,"readRa")),
	     (("copyAL",'A'),('a',Lft,"readRa")),
	     (("copyAL",'B'),('b',Lft,"readRa")),
	     (("readRa",'a'),('A',Lft,"copyAR")),
	     (("readRa",'b'),('A',Lft,"copyBR")),
	     (("readRa",'A'),('a',Lft,"finish")),

	     (("copyBL",'a'),('a',Rght,"copyBL")),
	     (("copyBL",'b'),('b',Rght,"copyBL")),
	     (("copyBL",' '),(' ',Lft,"readRb")),
	     (("copyBL",'A'),('a',Lft,"readRb")),
	     (("copyBL",'B'),('b',Lft,"readRb")),
	     (("readRb",'a'),('B',Lft,"copyAR")),
	     (("readRb",'b'),('B',Lft,"copyBR")),
	     (("readRb",'B'),('b',Lft,"finish")),

	     (("copyAR",'a'),('a',Lft,"copyAR")),
	     (("copyAR",'b'),('b',Lft,"copyAR")),
	     (("copyAR",'A'),('a',Rght,"readL")),
	     (("copyAR",'B'),('a',Rght,"readL")),

	     (("copyBR",'a'),('a',Lft,"copyBR")),
	     (("copyBR",'b'),('b',Lft,"copyBR")),
	     (("copyBR",'A'),('b',Rght,"readL")),
	     (("copyBR",'B'),('b',Rght,"readL")),

	     (("finish",'a'),('a',Lft,"finish")),
	     (("finish",'b'),('b',Lft,"finish"))
             ]