Tennis Kata

-module(kata).
-export([call/2]).

point(0) -> love;
point(1) -> 15;
point(2) -> 30;
point(3) -> 40.

call(S,R) when S>=3,R>=3 ->
 case S-R of
   2  -> {game,server};
   1  -> {adv,server};
   0  -> deuce;
   -1 -> {adv,receiver};
   -2 -> {game,receiver}
 end;
call(4,_) -> {game,server};
call(_,4) -> {game,receiver};
call(S,R) -> {point(S),point(R)}.