[rules-users] Constants on LHS?

I have not been able to figure out how to define "constants" that can be used replace numbers, etc. on the LHS of rules, and am not quite at the stage where I can set up a DSL. Is there a way to accomplish this? For example, I have a simple rule to determine if glucose is below the targeted range; the lower limit of the target is 80. Quickest solution: when decision : GlucoseDecision(serumGlucoseConcentration < 80) then DO something But I want to be able to write: when decision : GlucoseDecision(serumClucoseConcentration < lowTargetLimit) then Do something so that I can set all these constants in one place, etc. Is there a way to accomplish this inside the DRL? - Mike