Rock, Scissor, Python

import random
ROCK=0
PAPER=1
SCISSORS=2

TIE=0
WIN=1
LOSS=2

def setup():
    rpsDict=dict()
    rpsDict['winLossTable']=createWinLossTable()
    indexToString=[None, None, None]
    indexToString[ROCK]='rock'
    indexToString[PAPER]='paper'
    indexToString[SCISSORS]='scissors'
    rpsDict['indexToString']=indexToString
    stringToIndex=dict()
    stringToIndex['rock']=ROCK
    stringToIndex['paper']=PAPER
    stringToIndex['scissors']=SCISSORS
    rpsDict['stringToIndex']=stringToIndex
    results=[None, None, None]
    results[TIE]='It was a tie this time.'
    results[WIN]='Congratulations, you win!'
    results[LOSS]='Looks like the computer beat you this round.'
    rpsDict['resultStrings']=results
    return rpsDict

def createWinLossTable():
    winLossTable=list()
    winLossTable.append([None, None, None])
    winLossTable.append([None, None, None])
    winLossTable.append([None, None, None])
    winLossTable[ROCK][ROCK]=TIE
    winLossTable[ROCK][PAPER]=LOSS
    winLossTable[ROCK][SCISSORS]=WIN
    winLossTable[PAPER][ROCK]=WIN
    winLossTable[PAPER][PAPER]=TIE
    winLossTable[PAPER][SCISSORS]=LOSS
    winLossTable[SCISSORS][ROCK]=LOSS
    winLossTable[SCISSORS][PAPER]=WIN
    winLossTable[SCISSORS][SCISSORS]=TIE
    return winLossTable

def main():
    rpsDict=setup()
    while True:
        runGame(rpsDict)
        playAgain=raw_input("Do you want to play again? (yes, no) ").lower()
        if playAgain in ('y', 'yes'):
            continue
        exit()

def runGame(rpsDict):
    while True:
        playerChoice=raw_input("\nRock, Scissors, or Paper? ").lower()
        try:
            playerChoice=rpsDict['stringToIndex'][playerChoice]
        except:
            print 'That choice is invalid.'
            continue
        break

    computerChoice=random.randint(0,2)
    print "The computer chose %s.\n" % rpsDict['indexToString'][computerChoice]

    result = rpsDict['winLossTable'][playerChoice][computerChoice]
    print rpsDict['resultStrings'][result]

if __name__=='__main__':
    main()