And most of us never see Lisp programmers hanging around. There [1] is a nice response to this post. And I totally agree with that.

[1] http://kawagner.blogspot.com/

Wait, you turned down someone’s request to buy a technical book?? And I’m supposed to take the rest of this article seriously? Not that I love the book but it seems very much penny wise, pound foolish to refuse book requests…

If there are other things twice as useful, you’d probably hear them in awkward places too. People just like to look as if they know something, which is even easier if there are names attached to it.

There are however still patterns of behaviour in functional programming, just no one has written enough about them yet to recognise the patterns. Todays patterns are tomorrows programming features and I think the reason Java’s patterns are so obvious is because of the more advanced languages like LISP.

A VP of Engineering vigorously trying to convince I should have used the Flyweight pattern in one of my programs. It turns out I was using the flyweight pattern – I just didn’t know it was now a pattern and had that name, and even though I explained how my program worked, since I didn’t say “flyweight” he felt I was missing the boat.

In a way you did in fact miss the boat. Patterns have two qualities. The immediate is as a blue-print for solving a specific class of problems. This is the aspect that most people (Especially programmers with lesser experience) focus on, because it makes the pattern a tool that they can use in their work. Used this way, the theory is, you may have a problem and you can then find a pattern that is designed to solve this problem and if you apply it, you have done good. This kind of thinking isn’t overly relevant for someone with much experience as a programmer; Indeed it may become more of a hindrance than a help.

The other quality of patterns is to form a common language to describe certain things that we, as programmers, do. I say “I’m using an abstract factory to decouple these two classes”, and you know what I mean. Such words make it easier for us to communicate with each other, so that we can discuss the really interesting stuff (Which is not the details of the “abstract factory” pattern).

Of course I can’t know the details of the situation you described above, but if you had known the concept of fly-weight pattern, you could have easier communicated your intend to him, instead of having to explain in detail how you program worked.

Sadly, I think that Java programmers (I mean programmers who exclusively program in Java) pay far more attention to this stuff than do other programmers. I’m not knocking Java, it’s fine. The problem is that it’s used exclusively in some places, and it doesn’t allow for people to understand how other paradigms, other languages, and the hardware itself actually function (and no, understanding the VM and understanding how the VM interacts with the CPU pipeline, the branch predictor, the instruction and data cache, etc., is entirely different… ).

I think you have hit on the single biggest problem with design patterns: people act as if it was something brand new that was introduced into the programming world and that it revolutionized it. In reality they just gave a name to something that had existed before.

They have revolutionized communication though. Having a conversation with someone and saying “apply the visitor pattern” instead of “traverse through the nodes of a tree and ” etc. etc. does have some merit.