Rules and Monads

Word of the day, Monad: I believe Leibnitz first applied it to science or perhaps philosophy. In any case, the word is defined as "...an indivisible, impenetrable unit of substance viewed as the basic constituent element of physical reality..."

I am currently contemplating a system that will allow the creation and testing of validity of atomical units, monads. Small units build up to larger units, to even larger, to ever so more larger. At the end, by testing the indivisible, impenetrable unit of substance, I can find out whether the sum of sums of sums of sums equaling to an even larger and more complicated entity is valid.

Well, solution one, write lots of lines of code and hope to God that nothing changes and your infinite amounts of if-then-else statements nested ever so many layers deep across ever so many classes in your lovely object oriented patterned out piece of shit.

Solution two requires a bit of imagination, a workflow, and rules on monads. Let's assume that you've built some wonderful gui that allows you to create and modify rules.

Now, each monad can actually be represented in a 2 dimensional space. Each monad is for a specific type of data: stock price, live stock, live stock weight, insurance policy, etc... Each monad represents a specific type of data. Let's say that's the X-axis. Each monad is also for a given instance of that data. For example, a price is uniquely identified as cusip/date, and each cow is uniquely identified by its id. Each transaction has a transaction id, etc... We can call this the Y-axis. So, given the X and the Y, we can uniquely identify every monad.

At this point, we can right a rule that tests that monad. So, we can test every indivisible unit, and then we can test the summation of these units using other rules that perhaps only group the indivisible monad rules. At the end, all this adds up to a single high level rule that tells you whether your data is valid or not. Along the way, your rules may change data, or take you on a different path, but that's another blog entry.

It's actually extremely elegant. I apologize if my description skewed the beauty or confused the matter. The more I think about this, the more I believe in it. Now you may be wondering: am I not describing an expert system built using a rule engine. Somewhat true, in fact I am describing an over simplified rule engine. The big difference is that instead of allowing each rule to be a self contained entity, this model assigns a rule to a particular type, and the rule outcome to the type and instance of the data object. So, instead of having a bunch of free for all rules, you have a controlled rule structure, and a controlled firing. This is one thing that I found to be very brittle in rule engines. The writer of the rules does not know when the rules will fire and has to be very careful in writing the rule filter. Now, some will argue that that's the whole point. Well, try selling a none-deterministic system to your business manager who is weary of the whole thing to begin with.

Anyways, as you can see I am a big fan of externalizing the ever changing business rules from the underlying system framework. This is an interesting idea, and really should be developed further.