First of all, you might tell us why you don't want to use modify? I
can't see any good reason for that.
I think a perfectly valid notation in your case would be :
(modify ?new (expense (+ 2000 ?new.expense)))
Now if you're not familiar with LISP-like notation, you have a lot of
guidance here:
Hello,
I agree with John, you should take a course through the tutorials first,
it would help you a lot.
Now, in your question, it seems that you need to access the slot of a
specific fact that you've just bound.
In this case, you can access slots directly with a "." (like an object
field):
Could you please show me the guidance???
I'm trying to modify the ?new fact for tallying his expenses, something like
this in Java code:
double expense = 1000;
expense = expense + 2000; // trying to get the previous amount add up with
the current amount
(deftemplate (slot name) (slot age) (slot
Jess is a rule language whose basic mechanism is pattern matching, which
binds pattern variables to constants. If you have a fact of the form
(person (name Fred) (age 22))
then you can issue a query of the form
(person (name ?name) (age ?age))
and it will bind ?name to Fred and ?age to 22 (if F