[jboss-jira] [JBoss JIRA] Commented: (JBRULES-1430) Improve Function feature

[Mark Proctor (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBRULES-1430?page=comments#action_12402420 ] 
            
Mark Proctor commented on JBRULES-1430:
---------------------------------------

Just as a reminder there is no function interface, it's just a static method call.

But you can do something like this:
function void addRule(String pkgName, String rule, RuleBase ruleBase ) {
   PackageBuilder builder = new PackageBuilder();
   builder.addPackgeFromDrl( new StringReader( rule ) );
   ruleBase.addPackage ( builder.addPackage() );
}


rule X
when
then
   String rule = "package org.drools.test\n global java.util.List list\n rule xxx\n when\n i:Integer()\nthen\n list.add(i);\nend";
    addRule( "org.domain", rule, drools.getWorkingMemory().getRuleBase() );
end


There is nothing stopping you passing drools.getWorkingMemory() and drools.getWorkingMemory().getRuleBase() as parameters.

The extra work needed, as described above, just to achieve this isn't trivial. But we will consider any robust patches you have.


> Improve Function feature
> ------------------------
>
>                 Key: JBRULES-1430
>                 URL: http://jira.jboss.com/jira/browse/JBRULES-1430
>             Project: JBoss Drools
>          Issue Type: Feature Request
>      Security Level: Public(Everyone can see) 
>          Components: All
>    Affects Versions: 4.0.4
>         Environment: all
>            Reporter: longDuck dong
>            Priority: Minor
>
> The current design of the Function is a bit limiting. for example, if I want to write a function to insert, update or retract facts, the current design does not support it. According to the docs http://downloads.jboss.com/drools/docs/4.0.4.17825.GA/html/ch06s04.html, functions are just helper methods. It would be more powerful if the function always passes the workingmemory to the function. This way, the functions can easily access the globals or access the rule engine. Basically, something similar to JESS funcall http://herzberg.ca.sandia.gov/docs/70/api/jess/Funcall.html.
> It also makes it easier for developers to encapsulate common actions in the consequence in a function and use it easily from a DSL. The pattern is well proven in CLIPS, JESS and haley.

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