You are now ready to try out act. Look at the definition of act
from CIRCLER. The only trader-state predicate it calls is at.
This means that, so long as you have a clause for at, you can test
this version of act. So input one - at(circler,18), perhaps - and then
type
act( circler, Action, Arg1, Arg2 ).You should find that Action becomes
move, Arg1 is whichever square is
clockwise of the current one, and Arg2 is dummy.
All this may have seemed rather long-winded, but the gist of it can be
stated quickly. To run a trader, you call run, passing it the trader's
name and initial square. To find out what the trader will do next, run
calls act, passing the trader's name in the first argument, and
getting back the name of an action, plus some other information in the
other arguments. act has two sources of information. The first is the
board predicates.
The second is the predicates that describe a
trader's current state. All these take the trader's name as their first
argument. As run proceeds, it updates these.
If you want to continue
a run from where it left off, perhaps after changing some of the state
predicates, you can use go_on. This takes one argument, the trader's
name. Finally, you can of course ask questions that involve act
directly, if you want to test how it responds to various situations.