In the examples above, all the rules' primitive conditions were simple
``words'' like hot and mp. It is possible to have more
complex conditions, which is where a connection with logic comes in. For
an example, have a look at the first two rules below. Ignore the third
one for the moment: it's another trick for killing the bug once enough
inferences have been made.
likes(mary,wine) => loves(john,mary). likes(mary,beer) => loves(bill,mary). loves(_,_) => exec([forward]), exec([right]).
You will find a copy of these in the file l1.pl, with the STM
initialised to likes(mary,wine). Try running them with
psworld0:
eps( l1, psworld0 ).You will see that the final contents of STM is as shown below.
loves(john, mary) (1.1) likes(mary, wine) (0.1)That is, the symbols
loves(john,mary) have been added. This was done
by firing the first rule. So groups of symbols can have a more
complicated structure than in the holidays example.