The forms in the body (the do property) of the scorekeeper
may be any of the forms listed here.
ScorekeeperForm: last-side-wins
If supplied as the only symbol in the body, then the scorekeeper implements the usual "last side left in the game wins" behavior.
ScorekeeperForm: if test action
If the test evaluates to true or any nonzero number,
then the action will be done.
ScorekeeperForm: cond (test actions...) ...
ScorekeeperForm: stop [message]
This stops the game immediately, with a draw for all sides.
ScorekeeperForm: win [sides] [own-message] [other-message]
ScorekeeperForm: lose [sides] [own-message] [other-message]
ScorekeeperForm: end [message]
This scorekeeper action ends the game immediately.
ScorekeeperForm: add exp [side]
This adds the result of evaluating exp to the score of the given side. The value may be a negative number.