The State of the Onion 10
by Larry Wall
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Pages: 1, 2, 3, 4, 5
So, then, how do we raise a family according to the various computing paradigms?
Imperative programming is the Father Knows Best approach. It only works at all when Father does know best, which is not all that often. Often Mother knows "bester" than Father. Hi, Gloria. And a surprising amount of the time, it's the kids who know "bestest."
For some reason the Von Trapp family comes to mind. I guess you have to structure your family to make the Sound of Music together.
"Look, if you hit your sister, she will hit you back. Duh."
Obviously anyone who doesn't program their family functionally has a dysfunctional family. But what does it mean to have a functional family? "Being hit back is a function of whether you hit your sister." On the surface, everything appears to be free of side effects. Certainly when I tell my kids to mind their manners it often seems to have no lasting effect. Really, though, it does, but in the typical family, there's a lot of hidden state change wound in the call stack. We first learn lazy evaluation in the family.
"Don't take the last piece of candy unless you really want it."
"Please define whether you really care, and exactly how much you care."
"I'm sure I care more than you do."
That's almost a direct quote from Heidi when she was young: "But I want it more than you do."
Functional programming tends to merge into declarative programming in general. I married into a family where you have to declare whether you want the last piece of cheesecake, or you're unlikely to get it.
Unfortunately, I grew up in more of a culture where it was everyone's responsibility to let someone else have the cheesecake. This algorithm did not always terminate. After several rounds of, "No, you go ahead and take it, no you take it, no you take it ..."
In the end, nobody was really sure who wanted the cheesecake. I guess you say it was a form of starvation. But when I married into my wife's family I found out that I definitely wouldn't get the cheesecake until I learned to predeclare.
Let's see, inheritance is obviously important, or you wouldn't have a family in the first place. On the other hand, the family is where culture is handed down in the form of design patterns. A good model of composition is important--a lot of the work of being a family consists of just trying to stay in one spot together. As a form of composition, we learn how to combine our traits constructively by playing various roles in the family. Sometimes those are fixed roles built at family composition time, and sometimes those are temporary roles that are mixed in at run time. Delegation is also important. I frequently delegate to my sons: "Lewis, take the trash out."
That's Design By Contract. "Keep your promises, young man!"
Metaprogramming. "Takes one to know one!"
Aspected-oriented programming comes up when we teach our kids to evaluate their methods in the broader context of society:
"Okay kid, now that you've passed your driver's test, you still have to believe the stop signs, but when the speed limit sign says 65, what it really means is that you should try to keep it under 70. Or when you're in Los Angeles, under 80."
But I think the basic Perl paradigm is "Whatever-oriented programming."
Your kid comes to you and says, "Can I borrow the car?"
You say: "May I borrow the car?"
They say: "Whatever ..."
Should I push the door or pull it?
Actually, "whatever" is such an important concept that we built it into Perl 6. This is read, "from one to whatever."
You might ask why we can't just say "from one to infinity":
The problem is that not all operators operate on numbers:
Not all operators are ranges. Here's the sibling argument operator, which repeats the same words an arbitrary number of times:
Perl has always been about letting you care about the things you want to care about, while not caring about the things you don't want to care about, or that maybe you're not quite ready to care about yet. That's how Perl achieves both its accessibility and its power. We've just baked more of that "who cares?" philosophy into Perl 6.
A couple of years ago, Tim O'Reilly asked me what great problem Perl 6 was being designed to solve. This question always just sat in my brain sideways because, apart from Perl 0, I have never thought of Perl as the solution to any one particular problem. If there's a particular problem that Perl is trying to solve, it's the basic fact that all programming languages suck. Sort of the concept of original sin, applied to programming languages.
As parents, to the extent that we can influence the design of our kids, we design our kids to be creative, not to solve a particular problem. About as close as we get to that is to hope the kid takes over the family business, and we all know how often that sort of coercion works.
No, instead, we design our kids to be ready to solve problems, by helping them learn to be creative, to be socially aware, to know how to use tools, and maybe even how to manufacture the tools for living when they're missing. They should be prepared to do ... whatever.
Trouble is, it takes a long time to make an adult, on the order of 20 years. Most insects don't take 20 years to mature.
Apparently it takes you ten years to become an expert in being a kid, and then another ten years to become an expert in not being a kid. Some people never manage the second part at all, or have a strange idea of adulthood. Some people think that adulthood is when you just bake all your learning into hardware and don't learn anything new ever again, except maybe a few baseball scores. That's an oversimplified view of reality, much like building a hardwired Lisp machine. Neoteny is good in moderation. We have to be lifelong learners to really be adults, I think.
No, adulthood is really more about mature judgment. I think an adult is basically someone who knows when to care, and how to figure out when they should care when they don't know offhand. A teenager is forever caring about things the parents think are unimportant, and not caring about things the parents think are important. Well, hopefully not forever. That's the point. But it's certainly a long process, with both kids and programming languages.
In computer science, it is said that premature optimization is the root of all evil. The same is true in the family. In parenting terms, you pick your battlefields, and learn not to care so much about secondary objectives. If you can't modulate what you care about, you're not really ready to parent a teenager. Teenagers have a way of finding your hot buttons and pushing them just to distract you from the important issues. So, don't get distracted.
