Rob Pike's 5 Rules of Programming

(cs.unc.edu)

140 points | by vismit2000 2 hours ago

19 comments

  • embedding-shape 1 hour ago
    "Epigrams in Programming" by Alan J. Perlis has a lot more, if you like short snippets of wisdom :) https://www.cs.yale.edu/homes/perlis-alan/quotes.html

    > Rule 5. Data dominates. If you've chosen the right data structures and organized things well, the algorithms will almost always be self-evident. Data structures, not algorithms, are central to programming.

    Always preferred Perlis' version, that might be slightly over-used in functional programming to justify all kinds of hijinks, but with some nuance works out really well in practice:

    > 9. It is better to have 100 functions operate on one data structure than 10 functions on 10 data structures.

    • rsav 1 hour ago
      There's also:

      >I will, in fact, claim that the difference between a bad programmer and a good one is whether he considers his code or his data structures more important. Bad programmers worry about the code. Good programmers worry about data structures and their relationships.

      -- Linus Torvalds

    • alberto-m 8 minutes ago
      This quote from “Dive into Python” when I was a fresh graduate was one of the most impacting lines I ever read in a programming book.

      > Busywork code is not important. Data is important. And data is not difficult. It's only data. If you have too much, filter it. If it's not what you want, map it. Focus on the data; leave the busywork behind.

    • Intermernet 1 hour ago
      I believe the actual quote is:

      "Show me your flowchart and conceal your tables, and I shall continue to be mystified. Show me your tables, and I won't usually need your flowchart; it'll be obvious." -- Fred Brooks, The Mythical Man Month (1975)

      • bfivyvysj 55 minutes ago
        This is the biggest issue I see with AI driven development. The data structures are incredibly naive. Yes it's easy to steer them in a different direction but that comes at a long term cost. The further you move from naive the more often you will need to resteer downstream and no amount of context management will help you, it is fighting against the literal mean.
        • dotancohen 3 minutes ago
          Then don't let the AI write the data structures. I don't. I usually don't even let the AI write the class or method names. I give it a skeleton application and let it fill in the code. Works great, and I retain knowledge of how the application works.
        • Intermernet 45 minutes ago
          Naive doesn't mean bad. 99% of software can be written with understood, well documented data structures. One of the problems with ai is that it allows people to create software without understanding the trade offs of certain data structures, algorithms and more fundamental hardware management strategies.

          You don't need to be able to pass a leet code interview, but you should know about big O complexity, you should be able to work out if a linked list is better than an array, you should be able to program a trie, and you should be at least aware of concepts like cache coherence / locality. You don't need to be an expert, but these are realities of the way software and hardware work. They're also not super complex to gain a working knowledge of, and various LLMs are probably a really good way to gain that knowledge.

        • andsoitis 47 minutes ago
          > This is the biggest issue I see with AI driven development. The data structures are incredibly naive.

          Bill Gates, for example, always advocated for thinking through the entire program design and data structures before writing any code, emphasizing that structure is crucial to success.

          • neocron 35 minutes ago
            Ah Bill Gates, the epitome of good software
            • dotancohen 1 minute ago
              Yes, actually. Gates wrote great software.

              Microsoft is another story.

    • 0xpgm 17 minutes ago
      Reminded me of this thread between Alan Kay and Rich Hickey where Alan Kay thinks "data" is a bad idea.

      My interpretation of his point of view is that what you need is a process/interpreter/live object that 'explains' the data.

      https://news.ycombinator.com/item?id=11945722

      EDIT: He writes more about it in Quora. In brief, he says it is 'meaning', not 'data' that is central to programming.

      https://qr.ae/pCVB9m

    • mchaver 21 minutes ago
      I find languages like Haskell, ReScript/OCaml to work really well for CRUD applications because they push you to think about your data and types first. Then you think about the transformations you want to make on the data via functions. When looking at new code I usually look for the types first, specifically what is getting stored and read.
    • bandrami 1 minute ago
      Also basically everything DHH ever said (I stopped using Rails 15 years ago but just defining data relationships in YAML and typing a single command to get a functioning website and database was in fact pretty cool in the oughts).
    • JanisErdmanis 17 minutes ago
      With 100 functions and one datastructure it is almost as programming with a global variables where new instance is equivalent to a new process. Doesn’t seem like a good rule to follow.
    • Hendrikto 29 minutes ago
      I feel like these are far more vague and less actionable than the 5 Pike rules.
    • linhns 19 minutes ago
      Nice to see Perlis mentioned once in a while. Reading SICP again, still learning new things.
    • DaleBiagio 26 minutes ago
      " 9. It is better to have 100 functions operate on one data structure than 10 functions on 10 data structures."

      That's great

    • mpalmer 54 minutes ago
      Was the "J" short for "Cassandra"?

          When someone says "I want a programming language in which I need only say what I wish done," give him a lollipop.
    • mosura 1 hour ago
      Perlis is just wrong in that way academics so often are.

      Pike is right.

      • Intermernet 39 minutes ago
        Hang on, they mostly agree with each other. I've spoken to Rob Pike a few times and I never heard him call out Perlis as being wrong. On this particular point, Perlis and Pike are both extending an existing idea put forward by Fred Brooks.
        • mosura 26 minutes ago
          Perlis absolutely is not saying the same thing, and as the commenter notes the functional community interpret it in a particularly extreme way.

          I would guess Pike is simply wise enough not to get involved in such arguments.

      • jacquesm 29 minutes ago
        Perlis is right in the way that academics so often are and Pike is right in the way that practitioners often are. They also happen to be in rough agreement on this, unsurprisingly so.
      • hrmtst93837 18 minutes ago
        Treating either as gospel is lazy, Perlis was pushing back on dogma and Pike on theory, while legacy code makes both look cleaner on paper.
  • nateb2022 1 minute ago
    Previous discussion: https://news.ycombinator.com/item?id=15776124 (8 years ago, 18 comments)
  • piranha 44 minutes ago
    > Rule 5 is often shortened to "write stupid code that uses smart objects".

    This is probably the worst use of the word "shortened" ever, and it should be more like "mutilated"?

    • andsoitis 41 minutes ago
      Syntactic sugar is cancer of the semicolon.
      • franktankbank 8 minutes ago
        Tide goes in tide goes out, can't explain that.
  • CharlieDigital 56 minutes ago
    I feel like 1 and 2 are only applicable in cases of novelty.

    The thing is, if you build enough of the same kinds of systems in the same kinds of domains, you can kinda tell where you should optimize ahead of time.

    Most of us tend to build the same kinds of systems and usually spend a career or a good chunk of our careers in a given domain. I feel like you can't really be considered a staff/principal if you can't already tell ahead of time where the perf bottleneck will be just on experience and intuition.

    • PaulKeeble 50 minutes ago
      I feel like every time I have expected an area to be the major bottleneck it has been. Sometimes some areas perform worse than I expected, usually something that hasn't been coded well, but generally its pretty easy to spot the computationally heavy or many remote call areas well before you program them.

      I have several times done performance tests before starting a project to confirm it can be made fast enough to be viable, the entire approach can often shift depending on how quickly something can be done.

      • projektfu 7 minutes ago
        It really depends on your requirements. C10k requires different design than a web server that sees a few requests per second at most, but the web might never have been invented if the focus was always on that level of optimization.
      • pydry 22 minutes ago
        The number 1 issue Ive experienced with poor programmers is a belief that theyre special snowflakes who can anticipate the future.

        It's the same thing with programmers who believe in BDUF or disbelieve YAGNI - they design architectures for anticipated futures which do not materialize instead of evolving the architecture retrospectively in line with the future which did materialize.

        I think it's a natural human foible. Gambling, for instance, probably wouldnt exist if humans' gut instincts about the future were usually realistic.

        This is why no matter how many brilliant programmers scream YAGNI, dont do BDUF and dont prematurely optimize there will always be some comment saying the equivalent of "akshually sometimes you should...", remembering that one time when they metaphorically rolled a double six and anticipated the necessary architecture correctly when it wasnt even necessary to do so.

        These programmers are all hopped up on a different kind of roulette these days...

    • Bengalilol 33 minutes ago
      > you can kinda tell where you should optimize ahead of time

      Rules are "kinda" made to be broken. Be free.

      I've been sticking to these rules (and will keep sticking to them) for as long as I can program (I've been doing it for the last 30 years).

      IMHO, you can feel that a bottleneck is likely to occur, but you definitely can't tell where, when, or how it will actually happen.

    • HunterWare 48 minutes ago
      ROFL, I wish Pike had known what he was talking about. /s ;)
    • relaxing 49 minutes ago
      Rob Pike wrote Unix and Golang, but sure, you’re built different.
      • andsoitis 43 minutes ago
        > Rob Pike wrote Unix

        Unix was created by Ken Thompson and Dennis Ritchie at Bell Labs (AT&T) in 1969. Thompson wrote the initial version, and Ritchie later contributed significantly, including developing the C programming language, which Unix was subsequently rewritten in.

        • 9rx 13 minutes ago
          Pike didn’t create Unix initially, but was a contributor to it. He, with a team, unquestionably wrote it.
      • Intermernet 34 minutes ago
        Rob Pike is responsible for many cool things, but Unix isn't one of them. Go is a wonderful hybrid (with its own faults) of the schools of Thompson and Wirth, with a huge amount of Pike.

        If you'd said Plan 9 and UTF-8 I'd agree with you.

        • jacquesm 26 minutes ago
          Rob Pike definitely wrote large chunks of Unix while at Bell Labs. It's wrong to say he wrote all of it like the GP did but it is also wrong to diminish his contributions.

          Unless you meant to imply that UNIX isn't cool.

  • keyle 41 minutes ago
    Rule 5 is definitely king. Code acts on data, if the data is crap, you're already lost.

    edit: s/data/data structure/

    • andsoitis 39 minutes ago
      … if the data structures are crap.

      Good software can handle crap data.

      • keyle 38 minutes ago
        That is not what I meant. I meant crap data structures. Sorry it's late here.
  • DaleBiagio 27 minutes ago
    The attribution to Hoare is a common error — "Premature optimization is the root of all evil" first appeared in Knuth's 1974 paper "Structured Programming with go to Statements."

    Knuth later attributed it to Hoare, but Hoare said he had no recollection of it and suggested it might have been Dijkstra.

    Rule 5 aged the best. "Data dominates" is the lesson every senior engineer eventually learns the hard way.

  • kleiba 1 hour ago
    I believe the "premature evil" quote is by Knuth, not Hoare?!
    • swiftcoder 1 hour ago
      Potentially its by either (or even both independently). Knuth originally attributed it to Hoare, but there's no paper trail to demonstrate Hoare actually coined it first
      • Intermernet 33 minutes ago
        Turns out that premature attribution is actually the root of all evil...
      • Bengalilol 30 minutes ago
        Every empirical programmer will, at some point, end up yelling it out loud (too).
  • tobwen 1 hour ago
    Added to AGENTS.md :)
    • ozgrakkurt 44 minutes ago
      Would be cool to see the live reaction of Rob Pike to this comment
    • wwweston 49 minutes ago
      How good is your model at picking good data structures?

      There’s several orders of magnitude less available discussion of selecting data structures for problem domains than there is code.

      If the underlying information is implicit in high volume of code available then maybe the models are good at it, especially when driven by devs who can/will prompt in that direction. And that assumption seems likely related to how much code was written by devs who focus on data.

  • heresie-dabord 1 hour ago
  • doe88 21 minutes ago
    Great rules, but Rule 3.: WOW, so true, so well enunciated, masterful.
  • Devasta 17 minutes ago
    > "Premature optimization is the root of all evil."

    This Axiom has caused far and away more damage to software development than the premature optimization ever will.

    • gjadi 3 minutes ago
      Because people only quote it partially.

      > We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%.

  • Mercuriusdream 55 minutes ago
    never expected it to be a single HTML file so kind of surprised, but straight to the point, to be honest.
  • elcapitan 24 minutes ago
    Meta: Love the simplicity of the page, no bullshit.

    Funny handwritten html artifact though:

        <title> <h1>Rob Pike's 5 Rules of Programming</h1> </title>
  • anthk 48 minutes ago
    9front it's distilled Unix. I corrected Russ Cox' 'xword' to work in 9front and I am just a newbie. No LLM's, that's Idiocratic, like the movie; just '9intro.us.pdf' and man pages.

    LLM's work will never be reproducible by design.

  • openclaw01 24 minutes ago
    [dead]
  • Iamkkdasari74 7 minutes ago
    [dead]
  • catchcatchcatch 1 hour ago
    [dead]
  • seedpi 31 minutes ago
    [flagged]
  • bsenftner 1 hour ago
    Obvious. Why the elevation of the obvious?
    • DrScientist 1 hour ago
      I think for people starting out - rule 5 isn't perhaps that obvious.

      > Rule 5. Data dominates. If you've chosen the right data structures and organized things well, the algorithms will almost always be self-evident. Data structures, not algorithms, are central to programming.

      If want to solve a problem - it's natural to think about logic flow and the code that implements that first and the data structures are an after thought, whereas Rule 5 is spot on.

      Conputers are machines that transform an input to an output.

      • TheOtherHobbes 0 minutes ago
        I mean - no. If you're coming to a completely new domain you have to decide what the important entities are, and what transformations you want to apply.

        Neither data structures nor algorithms, but entities and tasks, from the user POV, one level up from any kind of implementation detail.

        There's no point trying to do something if you have no idea what you're doing, or why.

        When you know the what and why you can start worrying about the how.

        Iff this is your 50th CRUD app you can probably skip this stage. But if it's green field development - no.

      • mosura 57 minutes ago
        > If want to solve a problem - it's natural to think about logic flow and the code that implements that first and the data structures are an after thought, whereas Rule 5 is spot on.

        It is?

        How can you conceive of a precise idea of how to solve a problem without a similarly precise idea of how you intend to represent the information fundamental to it? They are inseparable.

        • DrScientist 34 minutes ago
          Obviously they are linked - the question is where do you start your thinking.

          Do you start with the logical task first and structure the data second, or do you actually think about the data structures first?

          Let's say I have a optimisation problem - I have a simple scoring function - and I just want to find the solution with the best score. Starting with the logic.

          for all solutions, score, keep if max.

          Simple eh? Problem is it's a combinatorial solution space. The key to solving this before the entropic death of the universe is to think about the structure of the solution space.

    • praptak 1 hour ago
      A good chunk of great advice is obvious things that people still fail to do.

      That's why a collection of "obvious" things formulated in a convincing way by a person with big street cred is still useful and worth elevating.

      • pm215 50 minutes ago
        Also, "why these 5 in particular" is definitely not obvious -- there are a great many possible "obvious in some sense but also true in an important way" epigrams to choose from (the Perlis link from another comment has over a hundred). That Pike picked these 5 to emphasise tells you something about his view of programming, and doubly so given that they are rather overlapping in what they're talking about.
    • HunterWare 49 minutes ago
      Can't be but so obvious if the first comment I saw here was that the first two rules didn't seem so important. =)
    • bazoom42 1 hour ago
      Definitely not obvious to everybody.
    • pjc50 1 hour ago
      You've got to elevate some obviously correct things, otherwise social media will fill the void with nonobviously incorrect things.
      • mosura 54 minutes ago
        Better to have 100 comments on one topic than 10 comments on 10 topics.