[rules-users] Expert Systems and Functional programming?

Ciao everybody, I have a question I would like to submit to this community, given Drools is my preferred choice for Expert Systems :) A quick background: I'm not an Expert Systems / Rule engines expert, but I'm a happy power user "of Rules" since my CS Engineering thesis, a paper published, and used it with happy results at work and hobby projects. Currently boarded on a new project with Rules+Processes at work, and still very happy, so happy, I'm using Drools again in a new hobby project. [semi-brag-mode off] Now, in recent times, I cannot ignore what (apparently) is a strong renaissance of Functional Programming, specifically all this momentum which Scala and Java 8's Lambda's are getting. The Question I'm asking myself: is there a specific, or few, areas where Functional Programming could actually benefit Expert Systems so much to actually spawn new paradigms of writing Rules? Or benefit in a new generation of the Rete algorithm? Or actually, Functional Programming will spawn a completely different paradigm of system which will go beyond Expert Systems the way are designed today? Ignore my rant if you feel it's too generic, but I really wanted to seize a chance to ask the question to this community :) Thank you for your feedback, Ciao, Matteo