Ability to negate a constraint group ------------------------------------ Key: JBRULES-1559 URL: http://jira.jboss.com/jira/browse/JBRULES-1559 Project: JBoss Drools Issue Type: Feature Request Security Level: Public (Everyone can see) Components: Drl Parser/Builder Affects Versions: FUTURE Reporter: Dirk Bergstrom Assigned To: Mark Proctor Priority: Minor I want to write a rule that says "Find all long-eared dogs that do not have short, black hair". This seems like the simple way to do it: collect( Dog( ears=="long", not (hair=="short" && color=="black") ) But that doesn't parse. Some digging through the archives unearthed a mention of De Morgan's laws, which leads to: http://en.wikipedia.org/wiki/De_Morgan's_laws Which explains that I can instead write: collect( Dog( ears=="long", (hair!="short" || color!="black") ) Which, after some mental effort, turns out to be the right thing. However, had I not found the reference to De Morgan's Law, it would have taken me a long time to get there (if indeed I ever would have). The end result is also quite difficult to parse if you're not a logician, and thus not very user-friendly. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.jboss.com/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira