Perlisisms (1982)

https://www.cs.yale.edu/homes/perlis-alan/quotes.html

by tosh • 1 month ago

139 61 1 month ago

cs.yale.edu

dtagames4• 1 month ago

And in #27 we find the rationale behind all LLM coding agents, "Once you understand how a program works, get someone else to write it for you."

hugo0vaz• 1 month ago

I think you misunderstood what the phrase actually means. You can only successfully manage or outsource a process once you understand it well enough to explain it. Therefore, most of the people doing agentic engineering are not following this Perlisim.

dtagames4• 1 month ago

Oh, that's exactly what I meant, except its corollary. People who do understand how software works should absolutely be having agents code it. And we do.

summa_tech2• 1 month ago

Once you understand how a program works, get someone else to write it for you. Then, you will quickly find out your understanding was insufficient.

dtagames4• 1 month ago

Is that ever true! I wrote a whole Medium article[0] about this, one of my most popular. It's called "YOU ARE BUGS" as a joke from Three Body Problem on Netflix.

[0] https://medium.com/gitconnected/you-are-bugs-improving-your-...

fhars• 1 month ago

The actual prescient LLM quote is "7. It is easier to write an incorrect program than understand a correct one."

sriram_malhar• 1 month ago

This feels so quaint today. How I'd like to be back in that timeframe.

chriscbr• 1 month ago

Random self plug - I liked a lot of these quotes from Alan Perlis, so around a year ago I bought the domain https://perl.is/ to display them.

summa_tech2• 1 month ago

Neat! What do you think about adding a "-2, -1, 0, +1, +2" agreement scale to each quote and showing the average instead of votes?

I think many of those are pretty subjective, and maybe not always right for everyone or for all time. But there are certainly going to be some universal pearls of wisdom, and neither of us can - by ourselves - tell which ones they are.

DonHopkins• 1 month ago

1. One man's constant is another man's variable.

Did you ever have one of those days when variables didn't and constants weren't?

layer83• 1 month ago

It constantly varies.

jancsika• 1 month ago

2. Functions delay binding; data structures induce binding. Moral: Structure data late in the programming process.

A good way to enforce this is to encrypt the data at the beginning of the process.

Then any function that returns structured data is clearly foolish and can be marked for removal.

geon• 1 month ago

What does the quote mean?

As you point out, I would prefer to parse a text string as early as possible, so that I could pass around structured data instead of having to parse the same string over and over.

That seems so obvious that I can't imagine what the author meant.

LelouBil2• 1 month ago

A programming language is low level when its programs require attention to the irrelevant.

Great definition actually

dundarious• 1 month ago

Relevance is relative, very much so.

xn7• 1 month ago

That makes that quote even better, no? What is relevant to you might not be relevant to me, the right level for you might too far low level for me.

marcosdumay• 1 month ago

Yes, that's the point.

hbcdbff• 1 month ago

Disagree - like many of the quotes on this page, it seems interesting at a very superficial level but upon further inspection turns out to be nonsensical.

If something requires attention, it’s by definition relevant

addaon• 1 month ago

"If something requires attention, it’s by definition relevant"

Not really. Consider an assembly language for a processor with a very orthogonal register set. The number of registers used by a block of code is relevant, but the identity of those registers isn't. That is, if the code can be written without spilling with six distinct, uniform registers, the choice of one of the 6! possible assignments of those six registers are irrelevant. But when writing that code, you still need to make the choice. And in real assembly languages, it's not necessarily obvious whether the choice here is arbitrary and unconstrained, or externally constrained (e.g. when choosing a mapping that avoids a move instruction by forcing the caller to pass a certain value in an agreed register; or when using an almost-orthogonal register set where it's unclear if later code cares that the value is left in a register that is also the possible target of a div instruction or something), so this requires attention at both write-time and read-time, even when irrelevant.

kbenson• 1 month ago

But relevant to what? Some things are relevant directly to the outcome by nature of what you're trying to express, while some other things are essentially incantations you need to repeat the same every time. Bad build systems and what you have to do to make them work are definitely relevant towards building a working program when you're using them, but at the same time the specific details are often somewhat irrelevant for your goal.

Also, many stupid or nonsensical statements can often yield wisdom if you meditate on them enough. Indeed, many (most?) zen koans are so simplistic that to get any usefulness out of them you have to insert you own assumptions and try to determine how it might apply.

munificent2• 1 month ago

If you want to go out of your way to interpret things as uncharitably as possible, you'll find yourself missing out on a lot of potential wisdom.

Obviously, it's relevant if the language itself forces the user to worry about some pointless minutia. The problem is that the language created that relevance, when it is otherwise irrelevant to the problem the user is trying to solve.

Forward declarations are relevant in C because the program won't compile without them. But they aren't relevant in any meaningful way to any domain a user might be writing C programs for.

rpdillon2• 1 month ago

These were published in the Communications of the ACM in the 1980s, I discovered them in the early 2000s, and have been reading them annually since. Every year, one of the ones that didn't make sense to me the previous year suddenly does.

In this particular quote, Perlis is talking about relevancy to the problem. He's hinting at the difference between incidental complexity and inherent complexity. Inherent complexity is a property of the problem, and incidental complexity is a property of the solution. He's arguing against solutions that bring incidental complexity that requires attention to aspects that aren't relevant to the problem.

msla• 1 month ago

OK, how is manual memory management relevant to writing a program to get weather information from an Internet API and display it to the user? In that context, "relevant" is the domains of getting the data (network communications) and displaying it (console vs GUI, converting units to the user's preferences, determining how much to show) and how the program internally manages its buffers is a distraction from those important concepts. Every line of code I have to write to ensure I have the space to store the data I need to work with is visual and cognitive noise, which is why programmers developed garbage collection.

LelouBil2• 1 month ago

Once you understand how to write a program get someone else to write it.

Pretty relevant with LLMs and coding agents.

ripe• 1 month ago

102. One can't proceed from the informal to the formal by formal means.

Seems to be a strike against LLM-based programming systems like Claude.

Sharlin• 1 month ago

To be fair, I don't think anyone is claiming that the process is anywhere close to formal. The word "vibe" implies anything except formality.

What Perlis probably meant that formal methods are useless unless you already have a formal specification. The formalization process itself is by necessity informal.

rezmason• 1 month ago

These are fun to say out loud in the voice of the Kai Lentit's Perl programmer

https://youtu.be/0jK0ytvjv-E?t=43

https://youtu.be/xE9W9Ghe4Jk?t=238

shawn_w2• 1 month ago

I read this as "Perlism" at first and got excited to see perl on HN.

cwnyth2• 1 month ago

One can dream...

zephen2• 1 month ago

Technically, I suppose, nightmares are dreams.

isityettime• 1 month ago

A language that doesn't affect the way you think about programming, is not worth knowing.

This one stood out to me. I'd say it's a favorite.

These others are interesting in the age of LLMs:

93. When someone says "I want a programming language in which I need only say what I wish done," give him a lollipop.
114. Within a computer natural language is unnatural.
115. Most people find the concept of programming obvious, but the doing impossible.
27. Once you understand how to write a program get someone else to write it.
113. The only constructive theory connecting neuroscience and psychology will arise from the study of software.

This one remains worth thinking about in terms of the consequences and costs of automation and computerization, LLM-powered or not:

99. In man-machine symbiosis, it is man who must adjust: The machines can't.

layer83• 1 month ago

Also: 102. One can't proceed from the informal to the formal by formal means.

zahlman• 1 month ago

99. In man-machine symbiosis, it is man who must adjust: The machines can't.

It seems worth noting here that the English verb "to adjust" is ambitransitive.

NuclearPM• 1 month ago

Why?

ebiederm• 1 month ago

36. The use of a program to prove the 4 color theorem will not change mathematics -- it merely demonstrates the theorem, a challenge for a century, is probably not important to mathematicians.

ink_13• 1 month ago

For the sake of completeness, the Four Colour Theorem was proved with the aid of a computer in 1976, although there were, er, quibbles with the original published result not finally put to bed until 1989. It was the first major theorem to be proved with computer assistance (Appel and Haken broke the theorem down to ~1400 configurations that were all computer verified).

isomorphic_duck• 1 month ago

Also 100, which speaks to the infinite demand of software - We will never run out of things to program as long as there is a single program around.

utopiah• 1 month ago

A language that doesn't affect the way you think about programming, is not worth knowing.

Yep I have it in https://fabien.benetou.fr/Languages/Languages#MakingYourOwn and few other places in my notes.

I keep it in mind especially when I discuss about programming with non programmers, arguing that the point isn't to bend a machine to your will but rather to become a better thinker. Getting machines to do what you need is "just" an extremely powerful side effect. This is also inspired by Papert and others.

rpdillon2• 1 month ago

My favorite has always been:

31. Simplicity does not precede complexity, but follows it.

Kind of close to "build the first one to throw away".

0xbadcafebee• 1 month ago

And then try not to fall into second system effect. So plan to build a third system...

userbinator• 1 month ago

Very ironic, considering the story of Perl 6.

jdw64• 1 month ago

In the long run every program becomes rococo - then rubble.

tenderfault• 1 month ago

76! Let’s do this!

gwern• 1 month ago

Full original version, without omissions or typos: https://gwern.net/doc/cs/algorithm/1982-perlis.pdf

benj111• 1 month ago

18. A program without a loop and a structured variable isn't worth writing

I kind of disagree. It may not be a very big or interesting program but a hell of a lot of useful stuff is done on spread sheets without any loops or anything but numbers.

jsrcout• 1 month ago

11. If you have a procedure with ten parameters, you probably missed some.

That brings back some memories. Just glad I eventually learned better.

Perlisisms (1982)

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