A dev team has been spending the past couple of weeks working on a 'generic rule engine' to validate a marketing process. The “Buy 5, get 10% off” kind of promotions.

The UI has all the great bits, drop-downs, various data lookups, etc etc..

What the dev is storing the database is the actual string representation FieldA=“Buy 5, get 10% off” that is “built” from the UI.

Might be OK, but now they want to apply that string to an actual order. Extract ‘5’, the word ‘Buy’ to apply to the purchase quantity rule, ‘10%’ and the word ‘off’ to subtract from the total.

Dev asked me:

Dev: “How can I use reflection to parse the string and determine what are integers, decimals, and percents?”
Me: “That sounds complicated. Why would you do that?”
Dev: “It’s only a string. Parsing it was easy. First we need to know how to extract numbers and be able to compare them.”
Me: “I’ve seen the data structures, wouldn’t it be easier to serialize the objects to JSON and store the string in the database? When you deserialize, you won’t have to parse or do any kind of reflection. You should try to keep the rule behavior as simple as possible. Developing your own tokenizer that relies on reflection and hoping the UI doesn’t change isn’t going to be reliable.”
Dev: “Tokens!...yea…tokens…that’s what we want. I’ll come up with a tokenizing algorithm that can utilize recursion and reflection to extract all the comparable data structures.”
Me: “Wow…uh…no, don’t do that. The UI already has to map the data, just make it easy on yourself and serialize that object. It’s like one line of code to serialize and deserialize.”
Dev: “I don’t know…sounds like magic. Using tokens seems like the more straightforward O-O approach. Thanks anyway.”

I probably getting too old to keep up with these kids, I have no idea what the frack he was talking about. Not sure if they are too smart or I’m too stupid/lazy. Either way, I keeping my name as far away from that project as possible.

Yes!! I've done it! CPU overunity!!!