You can demonstrate this in the following way. Do
This loads a simple version of act, driving a trader named circler.
To look at its definition, you can do showlib circler.pl.
There is one clause, which makes the circler
always move clockwise, never buying nor selling. Try
run( circler, 18 ).and see what happens.
Now, how can you try act for yourself? You need several things.
Firstly, the board-description predicates square, building, in,
loop,
adjacent,
clockwise,
distance,
sells,
buys and sells_fuel
must be in place. Well, this would have happened when you loaded
TRAVELLER.
Secondly, you need to fake up some facts which represent a circler at
some point in its travel. These are the ones defined by at,
carries, cash,
fuel, max_load, tank_size and total_load. These are
treated specially. As run proceeds, it updates
the knowledge base with these predicates. You can add your ``faked'' ones
via VED.