Re: slot values in facts needing to be bound...is there no way to express a fact with universally-quantified vars?
How about with a rule whose antecedent is trivially true and doesn't include the var? Sorry for the basic nature of this question...it hasn't been clear to me in the manual how jess' expressiveness may differ from fopc in general. -----Original Message----- From: "Wolfgang Laun" <[EMAIL PROTECTED]> To: [email protected] Sent: 10/7/08 8:29 PM Subject: Re: JESS: How to test if a var is bound/not-bound? There are several problems with this rule. The notion of a slot of some fact being bound doesn't make sense. A slot always has a value, possibly nil, and you can simply compare a slot to this symbol. You cannot simply write a boolean function as another term in a rule's LHS. So, the (< ...) must be wrapped in a test, but it would be better to have this test in the pattern for the currentTimeStep fact. The two opening parentheses after "=>" are in error. You cannot - and need not - re-assert ?Outcome. Use the modify function to update a fact's slot value, e.g., (modify ?Outcome (time ?T)) Please consult the Jess manual for more detailed explanations. -W On Tue, Oct 7, 2008 at 9:59 AM, David Pautler <[EMAIL PROTECTED]> wrote: > How can one test if a var is bound or not bound (rather than testing if it's > bound or not to a specific value)? > > For example, I would like to write something like this: > > (defrule causation-1 > "When a causal trigger is present, the outcome occurs" > (and (cause (trigger ?Trigger) (outcome ?Outcome)) > (test (not (bound ?Outcome.time))) ;test of > whether ?Outcome.time is bound > (currentTimeStep ?T) > (< ?Trigger.time ?T) ) > => > ((assert ?Outcome) > (bind ?Outcome.time ?T) )) > -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] -------------------------------------------------------------------- -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] --------------------------------------------------------------------
