1 files changed, 16 insertions, 6 deletions
diff --git a/tit4tat.pl b/tit4tat.pl
index 33abcb9..5eb54f4 100644
--- a/tit4tat.pl
+++ b/tit4tat.pl
@@ -24,11 +24,21 @@ step(A, B, PAY_A, PAY_B) :-
 	pay(A, B, PAY_A),
 	pay(B, A, PAY_B).
 
-loop(end).
-loop(OLD):- OLD\=end,
+% Use opponents last decision
+tit4tat_select(H,[H|_]).
+% Fallback to coorporate at beginning
+tit4tat_select(c,[]).
+
+tit4tat(A, Hist, PayA, PayB) :-
+	tit4tat_select(Old, Hist),
+	step(A, Old, PayA, PayB).
+
+loop(end, [_]).
+loop(End, Hist):- End\=end,
 	write('Type c,d or end to end: '), read(Word),
-	step(Word, OLD, PAY_A, PAY_B),
-	write('A Pay: '),write(PAY_A),nl, write('B Pay: '),write(PAY_B),nl,
-	loop(Word). 
+	tit4tat(Word, Hist, PAY_A, PAY_B),
+	write('A Pay: '),write(PAY_A),nl,
+	write('B Pay: '),write(PAY_B),nl,
+	loop(Word, [Word|Hist]). 
 	
-start:-loop(c).
+start:-loop(noend, []).