Re: JESS: [EXTERNAL] Matching facts based on a slot, but not the fact's type
Thank you; the template inheritance mechanism was the answer. Aurélien On Jul 30, 2013, at 8:11 AM, "Friedman-Hill, Ernest" wrote: > The short answer is “no”. Templates are like Java classes, and so this is > akin to asking if you can write Java code that reads the value of a “score” > member variable in any class. > > But you can use template inheritance to achieve your goal. Templates can > extend other templates; just put your “score” slot in a base template, and > extend everything else that needs a “score” slot from that common base, and > write your patterns to match the base template. Read about the use of > “extends” in templates here: > > http://www.jessrules.com/jess/docs/71/memory.html > > > From: owner-jess-us...@sandia.gov [mailto:owner-jess-us...@sandia.gov] On > Behalf Of Aurelien Mazurie > Sent: Friday, July 26, 2013 4:43 PM > To: jess-users > Subject: JESS: [EXTERNAL] Matching facts based on a slot, but not the fact's > type > > Dear Jess users, > I am still learning the ropes, and cannot find an answer to the following > question either online or in the 'Jess in action' book. Is there a way to > match facts in a LHS based on the presence of a slot? > > For example, I have two templates: > > (deftemplate A (slot score)) > (deftemplate B (slot score)) > > I would like my rule to be triggered if any fact (either from template A, B, > or others) have a 'score' slot with a specific value. For now I can do it by > manually adding references to A and B in the LHS, but this will not scale > well. I'm looking for a solution that can just work on any fact, regardless > of the template they are defined from. > > Best, > Aurelien
Re: JESS: [EXTERNAL] Matching facts based on a slot, but not the fact's type
What you are looking for is the capability of using interface names as template names in LHS code, which is not available in Jess. Using "extends" might help you to a certain extent, but that's restricted to the definition of a hierarchy. Also, consider that the solution to your problem might be a completely different approach to structuring your facts. -W On 26/07/2013, Aurelien Mazurie wrote: > Dear Jess users, > I am still learning the ropes, and cannot find an answer to the following > question either online or in the 'Jess in action' book. Is there a way to > match facts in a LHS based on the presence of a slot? > > For example, I have two templates: > > (deftemplate A (slot score)) > (deftemplate B (slot score)) > > I would like my rule to be triggered if any fact (either from template A, > B, or others) have a 'score' slot with a specific value. For now I can do > it by manually adding references to A and B in the LHS, but this will not > scale well. I'm looking for a solution that can just work on any fact, > regardless of the template they are defined from. > > Best, > Aurelien > To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' in the BODY of a message to majord...@sandia.gov, NOT to the list (use your own address!) List problems? Notify owner-jess-us...@sandia.gov.
RE: JESS: [EXTERNAL] Matching facts based on a slot, but not the fact's type
The short answer is "no". Templates are like Java classes, and so this is akin to asking if you can write Java code that reads the value of a "score" member variable in any class. But you can use template inheritance to achieve your goal. Templates can extend other templates; just put your "score" slot in a base template, and extend everything else that needs a "score" slot from that common base, and write your patterns to match the base template. Read about the use of "extends" in templates here: http://www.jessrules.com/jess/docs/71/memory.html From: owner-jess-us...@sandia.gov [mailto:owner-jess-us...@sandia.gov] On Behalf Of Aurelien Mazurie Sent: Friday, July 26, 2013 4:43 PM To: jess-users Subject: JESS: [EXTERNAL] Matching facts based on a slot, but not the fact's type Dear Jess users, I am still learning the ropes, and cannot find an answer to the following question either online or in the 'Jess in action' book. Is there a way to match facts in a LHS based on the presence of a slot? For example, I have two templates: (deftemplate A (slot score)) (deftemplate B (slot score)) I would like my rule to be triggered if any fact (either from template A, B, or others) have a 'score' slot with a specific value. For now I can do it by manually adding references to A and B in the LHS, but this will not scale well. I'm looking for a solution that can just work on any fact, regardless of the template they are defined from. Best, Aurelien
