Forth Rock Paper Scissors Lizard Spock

1 constant rock
2 constant paper
3 constant scissors
4 constant lizard
5 constant spock

: test-rock dup scissors = if s" rock crushes scissors" else lizard = if s" rock crushes lizard" else 0 then then ;
: test-paper dup rock = if s" paper covers rock" else spock = if s" paper disproves spock" else 0 then then ;
: test-scissors dup lizard = if s" scissors decapitates lizard" else paper = if s" scissors cuts paper" else 0 then then ;
: test-lizard dup paper = if s" lizard eats paper" else spock = if s" lizard poisons spock" else 0 then then ;
: test-spock dup rock = if s" spock vaporizes rock" else scissors = if s" spock smashes scissors" else 0 then then ;

: test dup rock = if drop test-rock else dup paper = if drop test-paper else dup scissors = if drop test-scissors else dup lizard = if drop test-lizard else spock = if test-spock then then then then then ;

: play 2dup = if ." Tie!" else 2dup test dup 0 = if drop swap test  ." Player 1 wins: " type else ." Player 2 wins: " type 2drop then then ;