Use a validationRule somewhere without xml tag validationRule

Hello,

I currently have a validationRule on an attribute that needs to be used only if there is a Patch and if the initial value is changed -> :
if((OPERATION.operation == ObjectOperation.PATCH) && CHANGES.attributeValueChanges("attribute")).

My question is : Can we use a validationRule in a script to play it ?

Example :

I have x validationRule on an attribute -> In a policy considering the operation I am doing, i want to use validationRule[0] or validationRule[1] and i can choose between all x validation rule.

I think it would be great to have something like this instead of playing with different policies.

Thanks