The expression of a Rule is evaluated to obtain the Rule’s value.
During development time, Rules are not evaluated until they are asked for – we call this "demanded." Until they are demanded, their value will be shown as "unbound." "Unbound" simply means that nothing has asked the Rule for its value yet.
If a Rule depends on other rules to calculate its value when it is evaluated, it will cause those rules to be evaluated also.
In this way, Knowledge Bridge evaluates only what is necessary to get a result that is demanded. This makes Knowledge Bridge very efficient
Forcing evaluation
You can manually trigger the evaluation of a rule while in the Model Context. In the Rules Grid, making sure you are in the Model context, simply click on the Evaluate Icon (
) for the rule.
After a rule is evaluated, this icon changes to Unbind icon 
These are toggles. That is, you can click Unbind Value and kBridge releases the demanded value and the Value column once again reads "unbound.'
