Tennis scoring

-module(tennis).
-export([score/2]).

nextPointCall(love)  -> 15;
nextPointCall(15) -> 30;
nextPointCall(30) -> 40.
score({advantage,Player},Scorer) when Player==Scorer -> {game,Player};
score({advantage,_},_) -> deuce;
score(deuce,Player) -> {advantage, Player};
score({30,40},server) -> deuce;
score({40,30},receiver) -> deuce;
score({40,_},server) -> {game,server};
score({_,40},receiver) -> {game,receiver};
score({S,R},server)   -> {nextPointCall(S),R};
score({S,R},receiver) -> {S,nextPointCall(R)}.