Thomas E. Kurtz has died

I know literally zero working programmers who learned programming the way Dijkstra thought it should be taught — not even Dijkstra himself, as Donald Knuth once gently pointed out.

Practically everybody in my generation started off with BASIC. On the other hand, at some point (when?), this practice stopped, and the newer generations turned out fine starting out with more civilized languages.

Consider me naive, but what way did Dijkstra thought it should be taught? Someone who first learned to code in QBASIC

He probably thought programming students should be taught Pascal, the academic language he pioneered. It is quite different from BASIC.

Pascal was Wirth, not Dijkstra.

Sorry, misremembering my meager computing history...

“On the Cruelty of Really Teaching Computer Science”[0]

[0] https://en.m.wikipedia.org/wiki/On_the_Cruelty_of_Really_Tea...

Dijkstra thought of computer science as a subdomain of mathematics, and thought that hands-on experimentation with actual computers would mostly lead students astray. A program should all be worked out and proven correct before (optionally) feeding it to a computer, and testing and even more so debugging were abhorrent practices.

BASIC, on the other hand, is more aligned with what Seymour Papert later came to call "Constructionism": the student learns by experimentation.

Other commenters are completely right to mention his concern for proofs and the "Cruelty of Really Teaching Computer Science", but the most BASIC-specific thing that he was associated with was criticism of the GOTO statement.

https://homepages.cwi.nl/~storm/teaching/reader/Dijkstra68.p...

In original BASIC, the GOTO is a foundational mechanism and a majority of programs would have used it, sometimes extensively. Dijkstra thought for many reasons that this wasn't good style and didn't promote clear thinking. And yes, one consequence of that is that it would be harder to prove programs correct or just to reason about whether they were correct.

Programs that overuse GOTOs (or from the point of view of later structured programming and functional programming advocates, perhaps programs that use GOTOs at all) were stigmatized as "spaghetti code".

https://en.wikipedia.org/wiki/Spaghetti_code

By the way, this concern is not just about aesthetics: some of the ideas that Dijkstra was advocating are arguably those that newer programming languages like Haskell and Rust can use to find bugs in code automatically at compile-time, or to make it harder to write certain bugs at all. The line between Dijkstra's advocacy and these techniques is complicated but I think there is a connection. So partly we might say that Dijkstra was not just concerned with how to make it easier for humans to think clearly about program correctness, but ultimately also about how to make it easier for computers to help humans automatically determine (parts of) program correctness. And it's true that the GOTO style complicates that task.

It is the "correct by construction" approach vs the "construct by correction" approach.

To be fair to Dijkstra, he was writing about how he believed university students should be taught. Two years before that cruelty paper was published, I was getting my first exposure ever to computer programming when my parents bought a Commodore 64 that came with a BASIC manual that showed how to make a Pong clone. I was 6 years old.

There's maybe an analogy to riding a bike. If you're aspiring to compete in a grand tour, you probably want power meters, lactate threshold and VO2 max tests in a lab, training that is principled and somewhat scientific in the way it builds toward a goal. If you're 6, your parents just put you on the seat and push you until your balance gets good enough that you can take the training wheels off.

Total aside: Training wheels are a thing I remember from my youth but today (at least here) they are barely used at all anymore.

I'm still used to the phrase (taking the training wheels off) but I'm fairly certain my kids will grow up not using it.

The sort of pushbikes for littler kids lets them learn balance and steering before also having to learn how to pedal and brake.

So half the learning happens on those pushbikes before they move to real bikes.

Kind of ironic that nowadays many people in our generation consider the newer generations to be lacking fundamental education because they never used GOTO based programming languages. I've talked to multiple people who lamented that young programmers have never done assembly or BASIC.

It’s helpful to have a mental model of how the computer works. I don’t know if it’s necessary that one have spent mountains of time building real software using a GOTO/jmp style, but having exposure to it would be nice, rather than hiding it away.

Jeff Dunteman’s assembly programming books included a “chapter 0” that I always loved, and which really stuck with me for how creatively they taught those topics.

I mean, CPUs do a bunch of work to make us believe they still operate just as a fast PDP-11, and I would wager that besides compiler experts that work on the backend parts of compilers, not many people have a real feel for modern hardware (obviously besides those that actually work on that given hardware).

So I'm not convinced that even those who think they know how it works know it actually.

Assembly? Sure, that has some educational value.

BASIC? That’s just nostalgia for poverty.

That's how it was with CS at Purdue when I was there in beginning of the 1990's.

It was Computational Science, not Computer Science, and was in the math department.

We did everything wiht pen and paper until I got into my 300 level classes and we got access to the NeXT cubes and IBM 3090.

I ended up switching to networking and the tech track, but it was definitely different...

Dijkstra was silly because everybody knows that Computer Science is the parent field of mathematics.

Mathematics is the study of all O(1) algorithms.

Computer Science is all other algorithms!

https://www.cs.utexas.edu/~EWD/transcriptions/OtherDocs/Hask... - describing why, in 2001, he thought Haskell was a good choice for a first college course in CS.

You can read many of his thoughts here: https://www.cs.utexas.edu/~EWD/welcome.html

Not entirely. GOTO can be pretty nice! And even the lack of structs probably has the advantage of helping to prepare you for today's world where column-major is back in style, for performance reasons.

Yes, Dijkstra was writing about the education of university students. I don't know whether he ever wrote anything about elementary school (or earlier) computer education, but I doubt he'd have approved of it, let alone of a hands on approach.

Ironically, I grew up with limited access to computers, so I wrote many programs on paper first, including a FORTH implementation in assembly language I wrote over summer break with a typewriter, waiting for school to start again so I could actually test it hands on.

> If you're 6, your parents just put you on the seat and push you until your balance gets good enough that you can take the training wheels off.

Which can take a very long time, because you have training wheels to begin with. If you're about to teach a kid how to ride a bicycle, it's far better to do without them. And the pedals too; learning how to use those is a huge distraction from learning to find and hold your balance.

There are special “kick bikes” for tiny tots to propel by kicking off the ground. And some of those can later be converted into “normal” bikes by attaching a chain drive, but... Feels kludgy, and is usually rather expensive.

If you can find an ordinary bike where you can get the saddle low enough for your kid to reach the ground with their feet, just remove the pedals and let them use that as a “kick bike”. If you can find a (gentle!) slope to practice on, you'll be able to replace the pedals in a matter of a few weeks at most, or probably days.

We need updated board games that replicate the function of a CPU.