Cognitive load is what matters

by zdw • 2 years ago

1769 721 2 years ago

xnx2• 2 years ago

This applies to user experience as well. I've seen designers focus on number of items or number of clicks when mental effort / cognitive load is what matters. Sometimes picking from a list of 50 links is easier. Sometimes answering 7 yes/no questions is easier.

dvt• 2 years ago

The companies where we were like ”woah, these folks are smart as hell” for the most part failed

Being clever, for the most part, almost never buys you anything. Building a cool product has nothing to do with being particularly smart, and scaling said product also rarely has much to do with being some kind of genius.

There's this pervasive Silicon Valley throughline of the mythical "10x engineer," mostly repeated by incompetent CEO/PM-types which haven't written a line of code in their lives. In reality, having a solid mission, knowing who your customer is, finding that perfect product market fit, and building something people love is really what building stuff is all about.

At the end of the day, all the bit-wrangling in the world is in service of that goal.

Scene_Cast2• 2 years ago

Depends on how you define smart. I worked at a place where income was directly tied to the quality of the ML models. Building what people love wouldn't have been the best strategy there.

jsd1982• 2 years ago

Only if your goal is to be an entrepreneur. Not everyone chases that goal nor considers success in that fashion.

Swizec2• 2 years ago

We can measure and quantify this cognitive load! I’ve been researching this for a book and have found some really cool research from ~10 years ago. It seems people stopped thinking about this around when microservices became popular (but they have the same problems just with http/grpc calls instead).

There are two main ways to measure this:

1. Cyclomatic/mccabe complexity tells you how hard an individual module or execution flow is to understand. The more decision points and branches, the harder. Eventually you get to “virtually undebuggable”

2. Architectural complexity measures how visible different modules are to each other. The more dependencies, the worse things get to work with. We can empirically measure that codebases with unclear dependency structures lead to bugs and lower productivity.

I wrote more here: https://swizec.com/blog/why-taming-architectural-complexity-...

The answer seems to be vertical domain oriented modules with clear interfaces and braindead simple code. No hammer factory factories.

PS: the big ball of mud is the world’s most popular architecture because it works. Working software first, then you can figure out the right structure.

rTX5CMRXIfFG2• 2 years ago

I’ve been interested in the same topic for a while now and the most difficult part, when explaining the concept to other programmers and defending against it in coding standards/reviews, is how to prove that cognitive load exists.

Cyclomatic complexity seems one indicator, but architectural complexity needs to be clarified. I agree that how much modules expose to each other is one trait, but again, needs clarification. How do you intend to go about this?

Been thinking about custom abstractions (ie those that you build yourself and which do not come from the standard libraries/frameworks) needed to understand code and simply counting them; the higher the number, the worse. But it seems that one needs to find something in cognitive psychology to back up the claim.

Swizec2• 2 years ago

Cyclomatic complexity seems one indicator, but architectural complexity needs to be clarified. I agree that how much modules expose to each other is one trait, but again, needs clarification. How do you intend to go about this?

Too much to summarize in a comment, I recommend reading the 3-blog series linked above. Architectural complexity is pretty well defined and we have an exact way to measure it.

Unfortunately there’s little industry tooling I’ve found to expose this number on the day-to-day. There’s 1 unpopular paid app with an awful business model – I couldn’t even figure out how to try it because they want you to talk to sales first /eyeroll.

I have some prototype ideas rolling around my brain but been focusing on writing the book first. Early experiments look promising.

There IS backing from cognitive research too – working memory. We struggle to keep track of more than ~7 independent items when working. The goal of abstraction (and this essay’s cognitive load idea) is to keep the number of independently moving or impacted pieces under 7 while working. As soon as your changes could touch more stuff than fits in your brain, it becomes extremely challenging to work with and you get those whack-a-mole situations where every bug you fix causes 2 new bugs.

energy1232• 2 years ago

This is true and valuable, but it's worth mentioning that some aspect of cognitive load is subjective. The code I write is always lower cognitive load to me than anyone else's code, even if my code has more cyclomatic complexity and code smells, because I've built up years of neural representations dedicated to understanding my favored way of doing things via practice and repetition. And I lack the neural representations needed to quickly understand other people's code if they approach things differently, even if their approach is just better.

This is not to say we should keep practicing our bad habits, but that we should practice good habits (e.g. composition over inheritance) as quickly as possible so the bad habits don't become ingrained in how we mentally process code.

ScotterC2• 2 years ago

Looks like a solid post with solid learnings. Apologies for hijacking the thread but I’d really love to have a discussion on how these heuristics of software development change with the likes of Cursor/LLM cyborg coding in the mix.

I’ve done an extensive amount of LLM assisted coding and our heuristics need to change. Synthesis of a design still needs to be low cognitive load - e.g. how data flows between multiple modules - because you need to be able to verify the actual system or that the LLM suggestion matches the intended mental model. However, striving for simplicity inside a method/function matters way less. It’s relatively easy to verify that an LLM generated unit test is working as intended and the complexity of the code within the function doesn’t matter if its scope is sufficiently narrow.

IMO identifying the line between locations where “low cognitive load required” vs “low cognitive load is unnecessary” changes the game of software development and is not often discussed.

codespin• 2 years ago

With LLM generated code (and any code really) the interface between components becomes much more important. It needs to be clearly defined so that it can be tested and avoid implicit features that could go away if it were re-generated.

Only when you know for sure the problem can't be coming through from that component can you stop thinking about it and reduce the cognitive load.

ScotterC2• 2 years ago

Agreed.

Regarding some of the ‘layered architecture’ discussion from the OP, I’d argue that having many modules that are clearly defined is not as large a detriment to cognitive load when an LLM is interpreting it. This is dependent on two factors, each module being clearly defined enough that you can be confident the problem lies within the interactions between modules/components and not within them AND sharing proper/sufficient context with an LLM so that it is focused on the interactions between components so that it doesn’t try to force fit a solution into one of them or miss the problem space entirely.

The latter is a constant nagging issue but the former is completely doable (types and unit testing helps) but flies in the face of the mo’ files, mo’ problems issue that creates higher cognitive loads for humans.

tkgally• 2 years ago

I’d really love to have a discussion on how these heuristics of software development change with the likes of Cursor/LLM cyborg coding in the mix

I would also be interested in reading people’s thoughts about how those heuristics might change in the months and years ahead, as reasoning LLMs get more powerful and as context windows continue to increase. Even if it never becomes possible to offload software development completely to AI, it does seem at least possible that human cognitive load will not be an issue in the same way it is now.

johnklos• 2 years ago

One way that I explain cognitive load to people unfamiliar with the term is to imagine crossing a lawn that has both autumn leaves and dog poop, and picture how much more mental energy one expends when trying to not step on dog poop.

rowanG0772• 2 years ago

Cognitive load is precisely why I love feature rich languages. Once you have internalized a language the features it has fall away in terms of cognitive load for me. In the same way I don't think about how to ride a bike while I'm riding a bike.

In most cases having a simpler language forces additional complexity into a program which does noticable add to cognitive load.

Etheryte2• 2 years ago

I think this works only up to the point where the language gets too large and starts creating extra cognitive load all by itself. For me, C++ is a good example of a language that has too many bells and whistles, if I have to stop what I'm doing to look up some weird syntax construct, then having all those extra features stops being useful.

rowanG0772• 2 years ago

I don't think largeness is the problem. It's language design. C++ is just really badly designed. I'd be very happy with a very large language that takes a long time to get familiar, if all the features in the language are well designed. IMO the current developer landscape is all about "fast onboarding", but that is the totally wrong metric to optimize for. To me it's the difference between someone walking and an airplane. Sure it's very easy to just start walking, you ain't going to go anywhere fast. On the other hand an airplane takes orders of magnitude longer to get going but once it does you won't ever catch up to it by walking.

lisper17• 2 years ago

OMG, so much this.

One of the biggest sources of cognitive load is poor language design. There are so many examples that I can't even begin to list them all here, but in general, any time a compiler gives you an error and tells you how to fix it that is a big red flag. For example, if the compiler can tell you that there needs to be a semicolon right here, that means that there does not in fact need to be a semicolon right there, but rather that this semicolon is redundant with information that is available elsewhere in the code, and the only reason it's needed is because the language design demands it, not because of any actual necessity to precisely specify the behavior of the code.

Another red flag is boilerplate. By definition boilerplate is something that you have to type not because it's required to specify the behavior of the code but simply because the language design demands it. Boilerplate is always unnecessary cognitive load, and it's one sign of a badly designed language. (Yes, I'm looking at you, Java.)

I use Common Lisp for my coding whenever I can, and one of the reasons is that it, uniquely among languages, allows me to change the syntax and add new constructs so that the language meets the problem and not the other way around. This reduces cognitive load tremendously, and once you get used to it, writing code in any other language starts to feel like a slog. You become keenly aware of the fact that 90% of your mental effort is going not towards actually solving the problem at hand, but appeasing the compiler or conforming to some stupid syntax rule that exists for no reason other than that someone at some time in the dim and distant past thought it might be a good idea, and were almost certainly wrong.

gleenn3• 2 years ago

Totally agree. I think the biggest and most important things a language designer chooses is what to disallow. For instance, private/package/public etc is one small example of an imposed restriction which makes it easier to reason about changing a large project because if e.g. something is private then you know it's okay and probably easy to refactor. The self-imposed restrictions save you mental effort later. I also love lisps but am a Clojure fan. This is because in Clojure, 90+% of the code is static functions operating on immutable data. That makes it extremely easy to reason about in the large. Those two restrictions are big and impose a lot of structure, but man I can tear around the codebase with a machete because there are so many things that code /can't do/. Also, testing is boneheaded simple because everything is just parameters in to those static functions and assert on the values coming out. I don't have to do some arduous object construction with all these factories if I need to mock anything, I can use "with-redefs" to statically swap function definitions too, which is clean and very easy to reason about. Choosing the things you mr language disallows is one of the most important things you can do to reduce cognitive load.

oalae5niMiel7qu8• 2 years ago

When the code needs to do something that it can't do, there is a massive cognitive load associated with figuring out how to do something approximating it. When the language or a framework is associated with lots of "how do I X" questions, the answers to which are all "completely rethink your program", that is evidence that the language/framework is not reducing cognitive load.

kvark• 2 years ago

I disagree with the first point. Say, the compiler figured out your missing semicolon. Doesn't mean it's easy for another human to clearly see it. The compiler can spend enormous compute to guess that, and that guess doesn't even have to be right! Ever been in a situation where following the compiler recommendation produces code that doesn't work or even build? We are optimizing syntax for humans here, so pointing out some redundancies is totally fine.

lisper17• 2 years ago

Doesn't mean it's easy for another human to clearly see it.

Why do you think that matters? If it's not needed, then it should never have been there in the first place. If it helps to make the program readable by humans then it can be shown as part of the rendering of the program on a screen, but again, that should be part of the work the computer does, not the human. Unnecessary cognitive load is still unnecessary cognitive load regardless of the goal in whose name it is imposed.

glitchc2• 2 years ago

No, as python and other languages amply demonstrate, the semicolon is for the compiler, not the developer. If the compiler is sophisticated enough to figure out that a semicolon is needed, it has become optional. That's the OP's point.

pwdisswordfishz• 2 years ago

Yes, semicolons are totally unnecessary. That’s why nobody who works on JavaScript has ever regretted that automatic semicolon insertion was added to the language. It has never prevented the introduction of new syntaxes to the language (like discussed here: <https://github.com/twbs/bootstrap/issues/3057#issuecomment-5...>), nor motivated the addition of awkward grammatical contortions like [no LineTerminator here].

christophilus• 2 years ago

There are plenty of languages that don’t require semicolons and yet manage to avoid those issues: Clojure, Go, Odin…

the__alchemist• 2 years ago

Great points. I strongly agree with your first point. Regrettably, I haven't used any language that solves this. (But believe it's possible, and you've demonstrated with one I haven't used).

I'm stuck between two lesser evils, not having the ideal solution you found: 1: Rust: Commits the sin you say. 2: Python, Kotlin, C++ etc: Commits a worse sin: Prints lots of words.. (Varying degrees depending on which of these), where I may or may not be able to tell what's wrong, and if I can, I have to pick it out of a text well.

Regarding boilerplate: This is one of the things I dislike most about rust. (As an example). I feel like prefixing`#[derive(Clone, Copy, PartialEq)]` on every (non-holding) enum is a flaw. Likewise, the way I use structs almost always results in prefixing each field with `pub`. (Other people use them in a different way, I believe, which doesn't require this)

wesselbindt4• 2 years ago

the compiler can tell you that there needs to be a semicolon right here

I can see that this is an annoyance, but does it really increase cognitive load? For me language design choices like allowing arbitrary arguments to functions (instead of having a written list of allowed arguments, I have to keep it in my head), or not having static types (instead of the compiler or my ide keeping track of types, I have to hold them in my head) are the main culprits for increasing cognitive load. Putting a semicolon where it belongs after the compiler telling me I have to is a fairly mindless exercise. The mental acrobatics I have to pull off to get anything done in dynamically typed languages is much more taxing to me.

lisper17• 2 years ago

Semicolons are just an example, and a fairly minor one. A bigger pet peeve of mine is C-style type declarations. If I create a binding for X and initialize it to 1, the compiler should be able to figure out that X is an integer without my having to tell it.

In fact, all type declarations should be optional, with run-time dynamic typing as a fallback when type inferencing fails. Type "errors" should always be warnings. There should be no dichotomy between "statically typed" and "dynamically typed" languages. There should be a smooth transition between programs with little or no compile-time type information and programs with a lot of compile-time type information, and the compiler should do something reasonable in all cases.

api• 2 years ago

I agree up until the end. Languages that let you change the syntax can result in stuff where every program is written in its own DSL. Ruby has this issue to some extent.

lisper17• 2 years ago

Sure, changing the syntax is not something to be done lightly. It has to be done judiciously and with great care. But it can be a huge win in some cases. For example, take a look at:

https://flownet.com/gat/lisp/djbec.lisp

It implements elliptic curve cryptography in Common Lisp using an embedded infix syntax.

bloopernova• 2 years ago

Regarding Common Lisp, do you know of any articles that highlight the methods used to "change the syntax and add new constructs so that the language meets the problem and not the other way around."

webnrrd2k2• 2 years ago

It's talking about lisp macros, idempotent languages, and a few other features of lispey languages. I'd suggest the book On Lisp, or Lisp in Small Pieces as good places to learn about it, but there are a ton of other resources that may be better suited to your needs.

deergomoo3• 2 years ago

Another red flag is boilerplate. By definition boilerplate is something that you have to type not because it's required to specify the behavior of the code but simply because the language design demands it. Boilerplate is always unnecessary cognitive load, and it's one sign of a badly designed language. (Yes, I'm looking at you, Java.)

The claim that LLMs are great for spitting out boilerplate has always sat wrong with me for this reason. They are, but could we not spend some of that research money on eliminating some of the need for boilerplate, rather than just making it faster to input?

JasonSage2• 2 years ago

Another red flag is boilerplate.

I have to disagree. Boilerplate can simply be a one-time cost that is paid at setup time, when somebody is already required to have an understanding of what’s happening. That boilerplate can be the platform for others to come along and easily read/modify something verbose without having to go context-switch or learn something.

Arguing against boilerplate to an extreme is like arguing for DRY and total prevention of duplicated lines of code. It actually increases the cognitive load. Simple code to read and simple code to write is low-cost, and paying a one-time cost at setup is low compared to repeated cost during maintenance.

singingfish3• 2 years ago

I've had some C# code inflicted on me recently that follows the pile of garbage design pattern. Just some offshore guys fulfilling the poorly expressed spec with as little brain work as possible. The amount of almost-duplicate boilerplate kicking around is one of the problems. Yeah it looks like the language design encourages this lowest common denominator type approach, and has lead into the supplier providing code that needs substantial refactoring in order be able to create automated tests as the entry points ignore separation of concerns and abuse private v public members to give the pretense of best practices while in reality providing worst practice modify this code at your peril instead. It's very annoying because I could have used that budget to do something actually useful, but on the other hand improves my job security for now.

oalae5niMiel7qu8• 2 years ago

If some program can generate that code automatically, the need to generate it, write it to disk, and for you to edit it is proof that there is some flaw in the language the code is written in. When the generator needs to change, the whole project is fucked because you either have to delete the generated code, regenerate it, and replicate your modifications (where they still apply, and if they don't still apply, it could have major implications for the entire project), or you have to manually replicate the differences between what the new version of the generator would generate and what the old version generated when you ran it.

With AST macros, you don't change generated code, but instead provide pieces of code that get incorporated into the generated code in well-defined ways that allow the generated code to change in the future without scuttling your entire project.

others to come along and easily read/modify something verbose without having to go context-switch or learn something.

They're probably not reading it, but assuming it's exactly the same code that appears in countless tutorials, other projects, and LLMs. If there's some subtle modification in there, it could escape notice, and probably will at some point. If there are extensive modifications, then people who rely on that code looking like the tutorials will be unable to comprehend it in any way.

PittleyDunkin• 2 years ago

Another red flag is boilerplate. By definition boilerplate is something that you have to type not because it's required to specify the behavior of the code but simply because the language design demands it.

Two things: 1) this is often not language design but rather framework design, and 2) any semantic redundancy in context can be called boilerplate. Those same semantics may not be considered boilerplate in a different context.

And on the (Common) Lisp perspective—reading and writing lisp is arguably a unique skill that takes time and money to develop and brings much less value in return. I'm not fan of java from an essentialist perspective, but much of that cognitive load can be offset by IDEs, templates, lint tooling, etc etc. It has a role, particularly when you need to marshall a small army of coders very rapidly.

lisper17• 2 years ago

If the world put even a tenth of the effort into training Lisp programmers as it does into training Java programmers you would have no trouble marshaling an army of Lisp programmers.

frenchslumber• 2 years ago

Completely agree! Common Lisp is truly the tool of the Gods.

nradov3• 2 years ago

The criticisms of Java syntax are somewhat fair, but it's important to understand the historical context. It was first designed in 1995 and intended to be an easy transition for C++ programmers (minimal cognitive load). In an alternate history where James Gosling and his colleagues designed Java "better" then it would have never been widely adopted and ended up as a mere curiosity like Common Lisp is today. Sometimes you have to meet your customers where they are.

It has taken a few decades but the latest version significantly reduces the boilerplate.

lisper17• 2 years ago

Sure. I understand why things are the way they are. But that I don't think that is a reason not to complain about the way things are. Improvement is always the product of discontent.

3abiton• 2 years ago

My gripe with the post is that there is no objective "cognitive load" solution. Arguably this varies from 1 person to another.

epolanski6• 2 years ago

I don't think you can have golden rules, if you do, you fall in the usual don't do X, or limit Y to Z lines, etc.

But what you _can_ do is to ask yourself whether you're adding or removing cognitive load as you work and seek feedback from (possibly junior) coworkers.

ants_everywhere• 2 years ago

This is true for exactly the same reason that no one algorithm compresses all types of data equally well.

jmyeet3• 2 years ago

So with semi-colons, you have three basic options:

1. Not required (eg Python, Go)

2. Required (eg C/C++, Java)

3. Optional (eg Javascript)

For me, (3) is by far the worst option. To me, the whole ASI debate is so ridiculous. To get away with (1), the languages make restrictions on syntax, most of which I think are acceptable. For example, Java/C/C++ allow you to put multiple statements on a single line. Do you need that? Probably not. I can't even think of an example where that's useful/helpful.

"Boilerplate" becomes a matter of debate. It's a common criticism with Java, for example (eg anonymous classes). I personally think with modern IDEs it's really a very minor issue.

But some languages make, say, the return statement optional. I actually don't like this. I like a return being explicit and clear in the code. Some will argue the return statement is boilerplate.

Also, explicit type declarations can be viewed as boilerplate.. There are levels to this. C++'s auto is one-level. So are "var" declarations. Java is more restrictive than this (eg <> for implied types to avoid repeating types in a single declaration). But is this boilerplate?

Common Lisp is where you lose me. Like the meme goes, if CL was a good idea it would've caught on at some point in the last 60 years. Redefning the language seems like a recipe for disaster, or at least adding a bunch of cognitive load because you can't trust that "standard" functions aren't doing standard things.

Someone once said they like in Java that they're never surprised by 100 lines of code of Java. Unlike CL, there's never a parser or an interpreter hidden in there. Now that's a testament to CL's power for sure. But this kind of power just isn't conducive to maintainable code.

epolanski6• 2 years ago

I like (3) to be honest and the number of times it has poised any issue is virtually 0.

medo-bear8• 2 years ago

Unlike CL, there's never a parser or an interpreter hidden in there

Ive never ever run into this problem in the years of writing common lisp. Can you show me an example code that has this? I wager you cannot and you are writing poopoo about something you know poo about and want it to be true just because you are too lazy to move beyond knowing poo

But this kind of power just isn't conducive to maintainable code.

I can usually run code decades old in common lisp. In fact this is one of its well known features. How much more maintainable can it possibly get :)

cess112• 2 years ago

You can reduce your Java boilerplate to annotations or succinct XML or whatever. Code generation is used a lot on the JVM.

Can you show a real compiler message about such a semicolon?

lisper17• 2 years ago

    % cat test.c
    main () {
      int x
      x=1
    }
    % gcc test.c  
    test.c:1:1: warning: type specifier missing, defaults to 'int' [-Wimplicit-int]
    main () {
    ^
    test.c:2:8: error: expected ';' at end of declaration
      int x
           ^
           ;
    1 warning and 1 error generated.

epolanski6• 2 years ago

The very same reasons you find CL to lower your cognitive load are why ultimately after 60 years all lisps have been relegated to niche languages despite their benefits, and I say it as a Racket lover. It raises cognitive load for everybody else by having to go through further steps into decoding your choices.

It's the very same reason why Haskell monocle-wielding developers haven't been able to produce one single killer software in decades: every single project/library out there has its own extensions to the language, specific compiler flags, etc that onboarding and sharing code becomes a huge chore. And again I say it as an avid Haskeller.

Haskellers know that, and there was some short lived simple Haskell momentum but it died fast.

But choosing Haskell or a lisp (maybe I can exclude Clojure somewhat) at work? No, no and no.

Meanwhile bidonville PHP programmers can boast Laravel, Symfony and dozens of other libraries and frameworks that Haskellers will never ever be able to produce. Java?

C? Even more.

The language might be old and somewhat complex, but read a line and it means the same in any other project, there are no surprises only your intimacy with the language limiting you. There's no ambiguity.

lisper17• 2 years ago

But choosing Haskell or a lisp (maybe I can exclude Clojure somewhat) at work? No, no and no.

I've been using CL at work for pretty much my entire career and have always gotten a huge amount of leverage from it.

tome4• 2 years ago

I’m surprised to hear this from an avid Haskeller and I think it might give the wrong impression to those who are less familiar with Haskell. I’m sure you know this, but for the benefit of others, projects don’t have their own extensions, they just may or may not use some of the extensions provided by GHC. Anyway, that practice is now diminishing given the GHC2021 and GHC2024 “standards”, which just enable a fixed set of stable extensions.

And regarding using specific compiler flags, well, projects almost never do that.

cognate3• 2 years ago

I dumped Haskell specifically because of its enormous cognitive load. All my time and energy went into Haskell and its endless quirks, leaving nothing for the business problem and its stakeholders.

isodev• 2 years ago

poor language design

We have an excellent modern-day example with Swift - it managed to grow from a simple and effective tool for building apps, to a “designed by committee” monstrosity that requires months to get into.

vonnik• 2 years ago

Totally agree with this and would add that cognitive load is not just a matter of the code before you, but a function of your total digital environment:

https://vonnik.substack.com/p/how-to-take-your-brain-back

Interruptions and distractions leave a cognitive residue that drastically reduces working memory through the Zeigarnik effect.

lr4444lr5• 2 years ago

Mantras like "methods should be shorter than 15 lines of code" or "classes should be small" turned out to be somewhat wrong.

So much this.

The whole point of functions and classes was to make code reusable. If the entire contents of a 100 line method are only ever used in that method and it's not recursive or using continuations or anything else weird, why the hell would it be "easier to read" if I had to jump up and down the file to 7 different submethods when the function's entire flow is always sequential?

Freak_NL3• 2 years ago

For unit testing those sub-sections in a clear and concise manner (i.e., low cognitive load). As long as the method names are descriptive no jumping to and fro is needed usually.

That doesn't mean every little unit needs to be split out, but it can make sense to do so if it helps write and debug those parts.

oxidant2• 2 years ago

Then you need to make those functions public, when the goal is to keep them private and unusable outside of the parent function.

Sometimes it's easy to write multiple named functions, but I've found debugging functions can be more difficult when the interactions of the sub functions contribute to a bug.

Why jump back and forth between sections of a module when I could've read the 10 lines in context together?

logicchains• 2 years ago

why the hell would it be "easier to read" if I had to jump up and down the file to 7 different submethods when the function's entire flow is always sequential?

If the submethods were clearly named then you'd only need to read the seven submethod names to understand what the function did, which is easier than reading 100 lines of code.

fragmede3• 2 years ago

Why is that any easier than having comments in the code that describe each part? In languages that don't allow closures, there's no good way to pass state between the seven functions unless you pass all the state you need, either by passing all the variables directly, or by creating an instance of a class/struct/whatever to hold those same variables and passing that. If you're lucky it might only be a couple of variables, but one can imagine that it could be a lot.

lr4444lr5• 2 years ago

If the variables were clearly named, I wouldn't have to read much at all, unless I was interested in the details. I reitrate: why does the length of the single function with no reuse matter?

joshuamorton8• 2 years ago

I find "is_enabled(x)" to be easier to reason about than

    if (x.foo || x.bar.baz || (x.quux && x.bar.foo))

Even if it's only ever used once. Functions and methods provide abstraction which is useful for more than just removing repetition.

gizzlon4• 2 years ago

Wouldn't you jump to is_enabled to see what it does?

That's what I always do in new code, and probably why I dislike functions that are only used once or twice. The overhead of the jump is not worth it. is_enabled could be a comment above the block (up to a point, notif it's too long)

emn13• 2 years ago

If you're literally using it just once, why not stick it in a local variable instead? You're still getting the advantage of naming the concept that it represents, without eroding code locality.

However, the example is a slightly tricky basis to form an opinion on best practice: you're proposing that the clearly named example function name is_enabled is better than an expression based on symbols with gibberish names. Had those names (x, foo, bar, baz, etc) instead been well chosen meaningful names, then perhaps the inline expression would have been just as clear, especially if the body of the if makes it obvious what's being checked here.

It all sounds great to introduce well named functions in isolated examples, but examples like that are intrinsically so small that the costs of extra indirection are irrelevant. Furthermore, in these hypothetical examples, we're kind of assuming that there _is_ a clearly correct and unique definition for is_enabled, but in reality, many ifs like this have more nuance. The if may well not represent if-enabled, it might be more something like was-enabled-last-app-startup-assuming-authorization-already-checked-unless-io-error. And the danger of leaving out implicit context like that is precisely that it sounds simple, is_enabled, but that simplicity hides corner cases and unchecked assumptions that may be invalidated by later code evolution - especially if the person changing the code is _not_ changing is_enabled and therefore at risk of assuming it really means whether something is enabled regardless of context.

A poor abstraction is worse than no abstraction. We need abstractions, but there's a risk of doing so recklessly. It's possible to abstract too little, especially if that's a sign of just not thinking enough about semantics, but also to abstract too much, especially if that's a sign of thinking superficially, e.g. to reduce syntactic duplication regardless of meaning.

shivawu• 2 years ago

I agree except I think 100 lines is definitely worth a method, whereas 15 lines is obviously not worthy for the most cases and yet we do that a lot.

My principle has always been: “is this part a isolated and intuitive subroutine that I can clearly name and when other people see it they’ll get it at first glance without pausing to think what this does (not to mention reading through the implemention)”. I’m surprised this has not been a common wisdom from many others.

toasterlovin• 2 years ago

Yeah, I find extracting code into methods very useful for naming things that are 1) a digression from the core logic, and 2) enough code to make the core logic harder to comprehend. It’s basically like, “here’s this thing, you can dig into it if you want, but you don’t have to.” Or, the core logic is the top level summary and the methods it calls out to are sections or footnotes.

andrewingram• 2 years ago

In recent years my general principle has been to introduce an abstraction (in this case split up a function) if it lowers local concepts to ~4 (presumably based on similar principles to the original post). I’ve taken to saying something along the lines of “abstractions motivated by reducing repetition or lines of code are often bad, whilst ones motivated by reducing cognitive load tend to be better”.

Good abstractions often reduce LOC, but I prefer to think of that as a happy byproduct rather than the goal.

zahlman12• 2 years ago

My principle has always been: “is this part a isolated and intuitive subroutine that I can clearly name and when other people see it they’ll get it at first glance without pausing to think what this does (not to mention reading through the implemention)”.

I hold this principle as well.

And I commonly produce one-liner subroutines following it. For me, 15 lines has become disturbingly long.

Mawr• 2 years ago

Because a function clearly defines the scope of the state within it, whereas a section of code within a long function does not. Therefore a function can be reasoned about in isolation, which lowers cognitive load.

lr4444lr5• 2 years ago

You can write long functions in a bad way, don't get me wrong. I'm just saying the rule that the length itself is an anti-pattern has no inherent validity.

kragen• 2 years ago

I don't agree. If there are side effects happening which may be relevant, the section of code within a long function is executing in a clearly defined state (the stuff above it has happened, the stuff below it won't happen until it finishes) while the same code in a separate function could be called from anywhere. Even without side effects, if it's called from more than one place, you have to think about all of its callers before you change its semantics, and before you look, you don't know if there is more than one caller. Therefore the section of code can be reasoned about with much lower cognitive load. This may be why larger subroutines correlate with lower bug rates, at least in the small number of published empirical studies.

The advantage of small subroutines is not that they're more logically tractable. They're less logically tractable! The advantage is that they are more flexible, because the set of previously defined subroutines forms a language you can use to write new code.

Factoring into subroutines is not completely without its advantages for intellectual tractability. You can write tests for a subroutine which give you some assurance of what it does and how it can be broken. And (in the absence of global state, which is a huge caveat) you know that the subroutine only depends on its arguments, while a block in the middle of a long subroutine may have a lot of local variables in scope that it doesn't use. And often the caller of the new subroutine is more readable when you can see the code before the call to it and the code after it on the same screen: code written in the language extended with the new subroutine can be higher level.

sureglymop• 2 years ago

As a non English speaker, what does "so much this" mean?

Does it essentially just mean "I agree"?

scott_w• 2 years ago

Yep, basically “I agree with this statement a lot.” It’s very much an “online Americanism.”

ericjmorey• 2 years ago

It's a call for others to take note of the important or profound message being highlighted. So more than just "I agree".

lr4444lr5• 2 years ago

In the superlative, yes. It's a fairly new phrase, and hardly in my parlance, but it's growing on me when I'm in informal typed chat contexts.

ziml772• 2 years ago

When someone says "this" they are basically pointing at a comment and saying "this is what I think too".

"So much" is applied to intensify that.

So, yes, it's a strong assertion of agreement with the comment they're replying to.

onionisafruit• 2 years ago

To paraphrase a recentish comment from jerf, “sometimes you just have a long list of tasks to do”. That stuck with me. Now I’m a bit quicker to realize when I’m in that situation and don’t bother trying to find a natural place to break up the function.

runevault2• 2 years ago

For me it depends. Sometimes I find value in making a function for a block of work I can give its own name to, because that can make the flow more obvious when looking at what the function does at a high level. But arbitrarily breaking up a function just because is silly and pointless.

tugu775• 2 years ago

A useful trick is to then at least visually structure those 150 lines with comments that separate some blocks of functionality. Keeps the linear flow but makes it still easier to digest.

westcoast49• 2 years ago

It comes down to the quality of the abstractions. If they are well made and well named, you'd rather read this:

  axios.get('https://api.example.com', {
      headers: { 'Authorization': 'Bearer token' },
      params: { key: 'value' }
  })
  .then(response => console.log(response.data))
  .catch(error => console.error(error));

than to read the entire implementations of get(), then() and catch() inlined.

lll-o-lll3• 2 years ago

The whole point of functions and classes was to make code reusable.

I’m amazed that here we are >40 years on from C++, and still this argument is made. Classes never encapsulated a module of reusability, except in toy or academic examples. To try and use them in this way either leads to gigantic “god” classes, or so many tiny classes with scaffolding classes between them that the “communication overhead” dwarfs the actual business logic.

Code base after code base proves this again and again. I have never seen a “class” be useful as a component of re-use. So what is? Libraries. A public interface/api wrapping a “I don’t care what you did inside”. Bunch of classes, one class, methods? So long as the interface is small and well defined, who cares how it’s structured inside.

Modular programming can be done in any paradigm, just think about the api and the internal as separate things. Build some tests at the interface layer, and you’ve got documentation for free too! Re-use happens at the dll or cluster of dll boundaries. Software has a physical aspect to it as well as code.

lr4444lr5• 2 years ago

This is not my experience. Multiple inheritance within a code base of certain sub-functionalities and states is a perfectly good example of reuse. You do not need to go all the way out to the library level. In fact, it is the abstract bases that really minimize the reusable parts that I find most useful.

I'm not saying you have to use classes to do this, but they certainly get the job done.

aiisjustanif• 2 years ago

Surely this is use case dependent? I’ve worked on projects where modular programming works well and others where not so much.

BenoitEssiambre• 2 years ago

Indeed and breaking out logic into more global scopes has serious downsides if that logic needs to be modified in the future, if your system still needs to support innovation and improvements, downsides not totally unlike the downsides of using a lot of global variables instead of local ones.

Prematurely abstracting and breaking code out into small high level chunks is bad. I try to lay it out from an information theoretic, mathematical perspective here:

https://benoitessiambre.com/entropy.html

with some implications for testing:

https://benoitessiambre.com/integration.html

It all comes down to managing code entropy.

zahlman12• 2 years ago

why the hell would it be "easier to read" if I had to jump up and down the file to 7 different submethods when the function's entire flow is always sequential?

Because you don't jump up and down the file to read it.

Each method that you create has a name, and the name is an opportunity to explain the process - naturally, in-line, without comments.

I write code like this all the time - e.g. from my current project: https://github.com/zahlman/bbbb/blob/master/src/bbbb.py . If I wanted to follow the flow of execution, I would be hammering the % key in Vim. But I don't do that, because I don't need or want to. The flow of the function is already there in the function. It calls out to other functions that encapsulate details that would be a distraction if I want to understand the function. The functions have names that explain their purpose. I put effort into names, and I trust myself and my names. I only look at the code I'm currently interested in. To look at other parts of the code, I would first need a reason to be interested in it.

When you look at yourself in the mirror, and notice your hand, do you feel compelled to examine your hand in detail before you can consider anything about the rest of your reflection? Would you prefer to conceive of that image as a grid of countless points of light? Or do you not find it useful that your mind's eye automatically folds what it sees into abstractions like "hand"?

35 years into my journey as a programmer, the idea of a 100-line function frightens me (although I have had to face this fear countless times when dealing with others' code). For me, that's half of a reasonable length (though certainly not a hard limit) for the entire file.

ajuc4• 2 years ago

    # Can't import at the start, because of the need to bootstrap the
    # environment via `get_requires_for_build_*`.

This comment is a great example of what information you lose when you split linear code into small interrelated methods. You lose ordering and dependencies.

Sometimes it's worth it. Sometimes it isn't. In my opinion it's almost never worth it to get to the Uncle Bob's approved length of methods.

10-30 lines is OK. 3 is counterproductive except for a small subset of wrappers, getters etc. Occasionally it's good to leave a method that is 300 lines long.

If your code always does 9 things in that exact order - it's counterproductive to split them artificially into 3 sets of 3 things to meet an arbitrary limit.

arzke2• 2 years ago

This is how I work as well, and the reason I tend to write many small functions rather than few large ones is precisely because it reduces cognitive load. You don't have to understand what the canSubmit function does, unless you are interested in knowing what the conditions to submit this form are.

Ironically, the author of the post claims it has the opposite effect.

afarviral2• 2 years ago

There's just no way I buy that I could safely make a change in a 100 loc function and know that there won't be an impact 30 lines down, where with a few additional function you can define the shape of interactions and know that if that shape/interface/type is maintained that there won't be unexpected interactions. Its a balance though as indirection can also readily hide and obscure interactions or add unnecessary glue code that also takes up mental bandwidth and requires additional testing to confirm.

Freak_NL3• 2 years ago

That short/long toggle in the top-right seems to expand and collapse the article. It defaults to short. Reading this article in its short form I kept wondering if I was missing something relevant (cognitive load++), but with the long form on I kept wondering if some paragraphs were explicitly intended to be superfluous or tangential (cognitive load++) for the sake of that collapsing trick.

For an article on cognitive load, using a gimmick which increases it seems ironic.

dangoodmanUT• 2 years ago

I thought these things were pretty inferable

BiteCode_dev3• 2 years ago

Something I noticed is that some vim / keyboard only envs are paying a huge cognitive load price by holding various states in their mind and having to expand efforts every time they switching context.

Sometimes there is the added burden of an exotic linux distro or a dvorak layout on a specially shaped keyboard.

Now, some devs are capable of handling this. But not all do, I've seen many claiming they are more productive with it, but when compared to others, they were less productive.

They were slow and tired easily. They had a higher burn out rate. The had too much to pay upfront for their day to day coding task but couldn't see that their idealization of their situation was not matching reality.

My message here is: if you are in such env be very honest with yourself. Are you good enough that you are among the few that actually benefit from it?

guywhocodes2• 2 years ago

Is this bait?

LAC-Tech4• 2 years ago

hi, tiling window manager and neovim user here.

I don't think about states much, it's all just muscle memory. Like doing a hadouken in street fighter.

BiteCode_dev3• 2 years ago

They all say that, but it's true for only 20% of my encounters when you actually watch them code next to others.

cainxinth• 2 years ago

I think it's all about the framework, the memory palace you build to keep things organized. A secondary factor is the freedom and solitude to prevent extraneous concerns from interrupting you. The brain is not great at true multitasking (doing two or more things at the same time), but it can juggle.

hn8726• 2 years ago

I agree with vast majority of the post, and it matches my experience. What I'm not sure I follow is the part about layered architecture, and what is offered as an alternative. The author quickly gets to a _conclusion_ that

So, why pay the price of high cognitive load for such a layered architecture, if it doesn't pay off in the future?

where one of the examples is

If you think that such layering will allow you to quickly replace a database or other dependencies, you're mistaken. Changing the storage causes lots of problems, and believe us, having some abstractions for the data access layer is the least of your worries.

but in my experience, it's crucial to abstract away — even if the interface is not ideal — external dependencies. The point is not to be able to "replace a database", but to _own_ the interface that is used by the application. Maybe the author only means _unnecessary layering_, but the way the argument is framed seems like using external dependency APIs throughout the entire app is somehow better.

master_crab2• 2 years ago

I commented on this in another thread here.

What I read it as is don’t over-index on creating separate layers/services if they are already highly dependent on each other. It just adds additional complexity tracing dependencies over the networking stack, databases/datastores, etc that the services are now split across.

In other words: a monolithic design is acceptable if the services are highly intertwined and dependent.

mrkeen6• 2 years ago

I think the 'Layered Architecture' section is all over the place.

There are a lot of terms thrown around with pretty loose definitions - in this article and others. I had to look up "layered architecture" to see what other people wrote about it, and it looks like an anti-pattern to me:

  In a four-layered architecture, the layers are typically divided into:
    Presentation
    Application
    Domain
    Infrastructure

  These layers are arranged in a hierarchical order, where each layer provides services to the layer above it and uses services from the layer below it, and each layer is responsible for handling specific tasks and has limited communication with the other layers. [1]

It looks like an anti-pattern to be because, as described, each layer depends on the one below it. It looks like how you'd define the "dependency non-inversion" principle. Domain depends on Infrastructure? A BankBalance is going to depend on MySQL? Even if you put the DB behind an interface, the direction of dependencies is still wrong: BankBalace->IDatabase.

Back to TFA:

In the end, we gave it all up in favour of the good old dependency inversion principle.

OK. DIP is terrific.

No port/adapter terms to learn

There is a big overlap between ports/adapters, hexagonal, and DIP:

  Allow an application to equally be driven by users, programs, automated test or batch scripts, and to be developed and tested in isolation from its eventual run-time devices and databases. [2]

That is, the Domain ("application") is at the bottom of the dependency graph, so that the Infrastructure {Programs, Tests, Scripts} can depend upon it.

If you think that such layering will allow you to quickly replace a database or other dependencies, you're mistaken.

Layering will not help - it will hinder, as I described above. But you should be able to quickly replace any dependency you like, which is what DIP/PortsAdapters/Hexagonal gives you.

Changing the storage causes lots of problems, and believe us, having some abstractions for the data access layer is the least of your worries. At best, abstractions can save somewhat 10% of your migration time (if any)

I iterate on my application code without spinning up a particular database. Same with my unit tests. Well worth it.

[1] https://bitloops.com/docs/bitloops-language/learning/softwar... [2] https://alistair.cockburn.us/hexagonal-architecture/

o_nate2• 2 years ago

If you feel like you are missing key parts of the argument, like I was, it might help to switch the view from "short" to "long" - there's a little slider on the right hand side of the screen. This adds in some paragraphs that help the piece flow better. (I'd never seen a blog post with this feature before.)

nogridbag3• 2 years ago

I agree. I find this part of the article weird as it has contracting statements:

No port/adapter terms to learn

and

we gave it all up in favour of the good old dependency inversion principle

Both use interfaces, just in different ways. We use hexagonal (ports and adapters) pattern in my project. If you asked anyone on my team to define hexagonal architecture they'll have no idea what you're talking about. They just follow the project coding patterns. There's no additional complexity.

If you think that such layering will allow you to quickly replace a database or other dependencies, you're mistaken

I think most people do not stay at companies long enough to see the price of not abstracting away these things. That's the next developer's problem. The code tends to be tightly coupled to the libraries and frameworks used. Eventually, the projects dependencies have to be upgraded (usually due to security issues) and the migrations are usually incredibly difficult, expensive, and fragile. The product's business logic is tightly coupled with the framework and libraries used at the time. Even if the company realizes that framework has no future, they're kind of locked into their initial decision made a decade ago. At least, that's been my experience.

We have two major products at my company. Both started with the same initial framework, but the project I architected that used hexagonal was migrated to a faster and more modern framework within 4 weeks. The other product had a multi-year migration to a newer version of the same framework (and by the time it was completed is already two major versions outdated). Both products are similar in scale and code size.

d0mine3• 2 years ago

What causes more cognitive load:

   filter(odd, numbers)

vs.

    (n for n in numbers if odd(n))

It depends on the reader too.

SoftTalker• 2 years ago

Also depends on whether it’s obvious why I need a list of odd numbers.

jodrellblank2• 2 years ago

Rather depends if we can trust that it's Python's "filter" or if it's another language you're making look Pythonic, and we don't know who implemented filter/2 or how.

- The first one might be an in-place filter and mutate "numbers", the second one definitely isn't.

- The first one might not be Python's filter and might be a shadowed name or a monkeypatched call, the second one definitely isn't.

- The first one isn't clear whether it filters odd numbers in, or filters them out, unless you already know filter/2; the second one is clear.

- The first one relies on you understanding first-class functions, the second one doesn't.

- The first one isn't clear whether it relies on `numbers` being a list or can work with any sequence, the second one clearly doesn't use list indexing or anything like it and works on any sequence that works in a `for` loop.

- The first one gives no hint what it will do on an empty input - throw an exception, return an error, or return an empty list. The second one is clear from the patterns of a `for` loop.

- The first one has a risk of hiding side-effects behind the call to filter, the second one has no call so can't do that.

- Neither of them have type declarations or hints, or give me a clue what will happen if "numbers" doesn't contain numbers.

- The first one isn't clear whether it returns a list or a generator, the second one explicitly uses () wrapper syntax to make a generator comprehension.

- The first one has a risk of hiding a bad algorithm - like copying "numbers", doing something "accidentally n^2" - while the second one is definitely once for each "n".

Along the lines of "code can have obviously no bugs, or no obvious bugs" the second one has less room for non-obvious bugs. Although if the reader knows and trusts Python's filter then that helps a lot.

Biggest risk of bugs is that odd(n) tests if a number is part of the OEIS sequence discovered by mathematician Arthur Odd...

jodrellblank2• 2 years ago

"Neither of them have type declarations or hints, or give me a clue what will happen if "numbers" doesn't contain numbers."

bools in Python are False==0 and True==1, and I'm now imagining an inexperienced dev believing those things are numbers and has no idea they could be anything else, and is filtering for Trues with the intent of counting them later on, but they messed up the assignment and instead of 'numbers' always getting a list of bools it sometimes gets a scalar single bool outside a list instead. They want to check for this case, but don't understand types or how to check them at all, but they have stumbled on these filter/loop which throw when run against a single answer. How useful! Now they are using those lines of code for control flow as a side effect.

d0mine3• 2 years ago

This is ridiculous. You can assume that you know what language you are reviewing/working in (sorry, I forgot to mention that the example is in Python). I can remember cases when I was not sure what [human] language I thinking in, but I don't remember a single case when there was a confusion what programming language I'm working in (it is not a factor in cognitive load).

filter is a builtin name in Python. There is no confusion here in practice. Static checker such as ruff will tell you if you attempt it accidentally. It is the first rule: A001 builtin-variable-shadowing.

If you are a noob the second variant may be easier to grasp. The first variant has less moving parts.

zahlman12• 2 years ago

The argument isn't about these minor syntactic or API differences. It's about the structure of the code, in the SICP (https://en.wikipedia.org/wiki/Structure_and_Interpretation_o...) sense.

d0mine3• 2 years ago

It is not how "cognitive load" is usually understood (as it relates to the working memory, measured by task-involved pupillary response). It involves anything and everything that is not already stored in your long term memory.

I remember spending egregiously long time to find a bug that was essentially a typo in some constant. Expressiveness of the language, how many chunks you have to keep in the working memory matters. The chunks can be low/high level depending on what you are trying to do at the moment but you can't escape looking at the low level details at some point.

fferen• 2 years ago

Disagree with first example. If that condition is only used once, adding a variable introduces more state to keep track of, that could just be a comment next to the conditional.

emptiestplace3• 2 years ago

The "too smart developers" narrative is pandering - poor design stems from inexperience and its accompanying insecurity, not intelligence. Skilled developers intuitively grasp the value of simplicity.

fallingknife• 2 years ago

I find that it comes most from intelligence. I see plenty of super experienced but not very smart engineers design terrible over engineered systems. On the other hand, juniors err in the opposite direction with long functions with deep nested branching and repetition. And the latter is better. Easier to refactor up in abstraction level than down.

emptiestplace3• 2 years ago

Perhaps I'm confused, but it seems to me that your examples actually support my point. You're describing experience-based patterns - seniors over-abstracting vs juniors writing tangled code. Neither case is about intelligence; they're about different types of inexperience leading to different design mistakes.

aulin• 2 years ago

the latter is not better though, it's terrible actually, deep nesting is the essence of cognitive load

nostradumbasp2• 2 years ago

I love what you're saying. But, I've met a lot of people who have say 10-20 years experience designing applications with unnecessary and sometimes incredible cognitive load. There are serious incentives to NOT write "simple" code, let me share a few of them.

Root causes from my perspective look like: 1. Job security type development. Fearful/insecure developers make serious puzzle boxes. "Oh yea wait until they fire me and see how much they need me, I'm the only one who can do this."

2. Working in a vacuum/black hole developers. Red flags are phrases like "snark I could have done this" when working together on a feature with them. Yes, that is exactly the point, and I even hope the junior comes in after and can build off of it too.

3. Mixing work with play "I read this blog post about category theory and found this great way to conceptualize my code through various abstractions that actually deter from runtime performance but sound really cool when we talk about it at lunch".

4. Clout/resume/ego chasing "I want to say something smart at stand up, a conference, or at a future job, so other people know they are not on my level and cannot touch my code or achieve my quality."

Some other red flags. They alone maintain their "pet" projects for everything serious until they couldn't. Minor problems/changes come up, someone else goes in and fixes it. Something serious happens it's a stop the world garbage collection for that developer and they are the only one who can fix it disrupting any other operations they were part of.

emptiestplace3• 2 years ago

I agree with everything you're saying, but these are different issues - not symptoms of excess intellect. Just post-hoc rationalization of poor choices.

marginalia_nu• 2 years ago

Yeah it's kind of a weird narrative. Writing complex code is leaps and bounds easier than writing simple code. Often takes both experience and intelligence to see the correct way.

deergomoo3• 2 years ago

Composition over inheritance is one of the most valuable lessons I learned earlier in my career as a developer. In fact these days, I'm hard-pressed to think of a case in which I would prefer inheritance as my first choice to model any problem. I'm sure there probably are some, but it feels too easy to wield irresponsibly and let bad design creep in.

At a previous job I had, a fairly important bit of code made use of a number of class hierarchies each five or six layers deep, including the massive code smell/design failure of certain layers stubbing out methods on a parent class due to irrelevancy.

To make matters worse, at the point of use often only the base/abstract types were referenced, so even working out what code was running basically required stepping through in a debugger if you didn't want to end up like the meme of Charlie from Always Sunny. And of course, testing was a nightmare because everything happened internally to the classes, so you would end up extending them even further in tests just to stub/mock bits you needed to control.

awinter-py• 2 years ago

AdminController extends UserController extends GuestController extends BaseController
Cognitive load in familiar projects -- If you've internalized the mental models of the project into your long-term memory, you won't experience a high cognitive load.

^ imo using third-party libraries checks both of these boxes because 1) a fresh-to-project developer with general experience may already know the 3rd party lib, and 2) third party libraries compete in the ecosystem and the easiest ones win

fmxsh2• 2 years ago

"Having too many shallow modules can make it difficult to understand the project. Not only do we have to keep in mind each module responsibilities, but also all their interactions."

Not only does it externalize internal complexity, but it creates emergent complexity beyond what would arise between and within deeper modules.

In a sense, shallow modules seem to be like spreading out the functions outside the conceptual class while thinking the syntactical encapsulation itself, rather than the content of the encapsulation, is the crucial factor.

euph0ria5• 2 years ago

Had to re-read this several times to grasp the meaning..

Curious, what is your background and day to day work to be able to express your thinking in these terms?

fmxsh2• 2 years ago

Thank you for asking! My phrasing may not have been the most clear.

My background is in humanities and health care. I currently work in eldercare. Computers have always been a major interest of mine since an early age, but professionally I have taken another route. I have a general curiosity about systems and theories of different kinds. I do have an education in the basic scientific approach, something I acquired while studying to become a teacher. Soft sciences have often come more easily to me. I lack the benefits of a disciplined study of computer science, something I am sure affects my approach.

My use of the word 'emergent' was inspired by systems theory [0], where the whole is more than the sum of its parts. The parts of a system create emergent behaviors or phenomena. For example: A football team consists of several players, and the strategy of the teamwork is an emergent phenomenon. Similarly, my thought was that when functions are spread out into several modules, they may create unexpected emergent complexity. Without being able to give a concrete example off the top of my head, I think I have struggled with bugs born out of such complexity.

My thought was that the "syntactical encapsulation" (the actual code we write) may not serve the "conceptual class" (the idea we have). We may have a good concept, but we distribute its functionality among too many classes.

[0] https://en.wikipedia.org/wiki/Systems_theory

master_crab2• 2 years ago

On the layered architecture section:

I have seen too many architectures where an engineer took “microservices” too far and broke apart services that almost always rely on each other into separate containers/VMs/serverless functions.

I’m not suggesting people build monolithic applications, but it’s not necessarily a good idea to break every service into its own distinct stack.

Aurornis• 2 years ago

Mantras like "methods should be shorter than 15 lines of code" or "classes should be small" turned out to be somewhat wrong.

These hard rules may be useful when trying to instill good habits in juniors, but they become counterproductive when you start constraining experienced developers with arbitrary limits.

It’s really bad when you join a team that enforces rules like this. It almost always comes from a lead or manager who reads too many business books and then cargo cults those books on to the team.

deergomoo3• 2 years ago

Same deal with DRY, the principle is obviously correct but people can take it too literally. It's so easy to get yourself in a huge mess trying to extract out two or three bits of code that look pretty similar but aren't really used in the same context.

skeeter2020• 2 years ago

The problem with DRY and generic rules around size, etc. really seems to be figuring out the boundaries, and that's tough to get right, even for experienced devs, plus very contextual. If you need to open up a dozen files to make a small change you're overwhelmed, but then if you need to wade through a big function or change code in 2 places you're just as frustrated.

quesomaster90007• 2 years ago

This is the bane of my existence at the moment after ~20 years into my career, and it frustrates me when I run into these situations when trying to get certain people to review pull requests (because I'm being kind, and adhering to a process, and there is really valuable feedback at times). But on the whole it's like being dragged back down to working at a snails pace.

- Can't refactor code because it changes too many files and too many lines.

- Can't commit large chunks of well tested code that 'Does feature X', because... too many files and too many lines.

- Have to split everything down into a long sequence of consecutive pull requests that become a process nightmare in its own right

- The documentation comments gets nitpicked to death with mostly useless comments about not having periods at the ends of lines

- End up having to explain every little detail throughout the function as if I'm trying to produce a lecture, things like `/* loop until not valid */ while (!valid) {...` seemed to be what they wanted, but to me it made no sense what so ever to even have that comment

This can turn a ~50 line function into a 3 day process, a couple of hundred lines into a multi-week process, and a thousand or two line refactor (while retaining full test coverage) into a multi-month process.

At one point I just downed tools and quit the company, the absurdity of it all completely drained my motivation, killed progress & flow and lead to features not being shipped.

Meanwhile with projects I'm managing I have a fairly good handle on 'ok this code isnt the best, but it does work, it is fairly well tested, and it will be shipped as the beta', so as to not be obstinate.

NotBoolean• 2 years ago

I don’t have your experience but I personally think some of this feedback can be warranted.

Can't refactor code because it changes too many files and too many lines.

This really depends on the change. If you are just doing a mass rename like updating a function signature, fair enough but if you changing a lot of code it’s very hard to review it. Lots of cognitive load on the reviewer who might not have the same understanding of codebase as you.

Can't commit large chunks of well tested code that 'Does feature X', because... too many files and too many lines.

Same as the above, reviewing is hard and more code means people get lazy and bored. Just because the code is tested doesn’t mean it’s correct, just means it passes tests.

Have to split everything down into a long sequence of consecutive pull requests that become a process nightmare in its own right

This is planning issue, if you correctly size tickets you aren’t going to end up in messy situations as often.

The documentation comments gets nitpicked to death with mostly useless comments about not having periods at the ends of lines

Having correctly written documentation is important. It can live a long time and if you don’t keep an eye on it can becomes a mess. Ideally you should review it before you submitting it to avoid these issues.

End up having to explain every little detail throughout the function as if I'm trying to produce a lecture, things like `/* loop until not valid */ while (!valid) {...` seemed to be what they wanted, but to me it made no sense what so ever to even have that comment

I definitely agree with this one. Superfluous comments are a waste of time.

Obviously this is just my option and you can take things too far but I do think that making code reviewable (by making it small) goes a long way. No one wants to review 1000s lines of code at once. It’s too much to process and people will do a worse job.

Happy to hear your thoughts.

nosefurhairdo• 2 years ago

That's rough. Of course some amount of thoughtfulness towards "smallest reasonable change" is valuable, but if you're not shipping then something is wrong.

As for the "comments on every detail" thing... I would fight that until I win or have to leave. What a completely asinine practice to leave comments on typical lines of code.

SeptiumMMX• 2 years ago

You always need to look at the track record of the team. If they were not producing solid consistent results before you joined them, it's a very good indicator that something's fishy. All that "they are working on something else that we can't tell you" is BS.

If they were, and you were the only one treated like that, hiring you was a decision forced upon the team, so they got rid of you in a rather efficient way.

lifeisstillgood• 2 years ago

I am trying my best to build in an inordinate amount of upfront linting and automated checks just to avoid such things - and then I still need to do a roadshow, or lots of explanations- but that’s probably good.

But the good idea is to say “we all have the same brutal linting standards (including full stops in docs!) - so hopefully the human linger will actually start reading the code for what it is, not what it says”

shinycode2• 2 years ago

No wonder why software development used to be expensive if 50 lines of code takes multiples days for several people …

spion• 2 years ago

Indeed, cognitive load is not the only thing that matters. Non-cognitive toil is also a problem and often enough it doesn't get sufficient attention even when things get really bad.

We do need better code review tools though. We also need to approach that process as a mechanism of effectively building good shared understanding about the (new) code, not just "code review".

spockz• 2 years ago

This sounds more like a case where you need a “break-the-glass” like procedure where some checks don’t apply. Or the checks should be non blocking anyway.

notShabu• 2 years ago

there is huge incentive for people who don't know how to code/create/do-stuff to slow things down like this b/c it allows them many years of runway at the company.

they are almost always cloaked in virtue signals.

almost every established company you join will already have had this process going for a long time.

doing stuff successfully at such a company is dangerous to the hierarchy and incurs an immune response to shut down or ostracize the doing-of-stuff successfully so the only way to survive or climb is to do stuff unsuccessfully (so they look good)

epolanski6• 2 years ago

You seem to be describing a company where bureaucracy is a feature not a bug.

Been there. Left, live thousands times better.

flakes2• 2 years ago

The documentation comments gets nitpicked to death with mostly useless comments about not having periods at the ends of lines End up having to explain every little detail throughout the function

For these cases I like to use the ‘suggest an edit’ feature on gitlab/github. Can have the change queued up in the comments and batch commit together, and takes almost no additional time/effort for the author. I typically add these suggestion comments and give an approve at the same time for small nitpicks, so no slow down in the PR process.

MarkMarine2• 2 years ago

I’m 15 years in and I feel basically the same. I end up making a feature or change, then going back and trying to split it into chunks that are digestible to my colleagues. I’ve got thousands of lines of staged changes that I’m waiting to drip out to people at a digestible pace.

I yearn for the early stage startup where every commit is a big change and my colleagues are used to reviewing this, and I can execute at my actual pace.

It’s really changed the way I think about software in general, I’ve come around to Rich Hickey’s radically simple language Clojure, because types bloat the refactors I’m doing.

I’d love to have more of you where I work, is there some way I can see your work and send some job descriptions and see if you’re interested?

jschrf2• 2 years ago

Aye. Sign of the times. You're 20+ years in, so I'm preaching to the choir and old-man-yelling-at-cloud here.

Cargo culting + AI are the culprits. Sucks to say, but engineering is going downhill fast. First wave of the shitularity. Architects? Naw, prompt engineers. Barf. Why write good code when a glorified chatbot could do it shittier and faster?

Sign of our times. Cardboard cutout code rather than stonemasonry. Shrinkflation of thought.

Peep this purified downvote fuel:

Everything is bad because everyone is lazy and cargo cults. Web specifically. Full-stop. AI sucks at coding and is making things recursively worse in the long run. LLMs are nothing more than recursive echo chambers of copypasta code that doesn't keep up with API flux.

A great example of this is the original PHP docs, which so, so many of us copypasta'd from, leading to an untold amount of SQL injections. Oopsies.

Simalarily and hunting for downvotes, React is a templating framework that is useful but does not even meet its original value proposition, which is state management in UI. Hilariously tragic. See: original example of message desync state issue on FB. Unsolved for years by the purported solution.

The NoSQL flash is another tragic comedy. Rebuilding the wheel when there is a faster, better wheel already carefully made. Postgres with JSONB.

GraphQL is another example of Stuff We Don't Need But Use Because People Say It's Good. Devs: you don't need it. Just write a query.

You mention a hugely important KPI in code. How many files, tools, commands, etc must I touch to do the simplest thing? Did something take me a day when it should have taken 30s? This is rife today, we should all pay attention. Pad left.

Look no further than hooks and contexts in React land for an example. Flawed to begin with, simply because "class is a yucky keyword". I keep seeing this in "fast moving" startups: the diaspora of business logic spread through a codebase, when simplicity and unity is key, which you touch on. Absolute waste of electricity and runway, all thanks to opiniation.

Burnt runways abound. Sometimes I can't help but think engineering needs a turn it off and then on again moment in safe mode without fads and chatbots.

gre• 2 years ago

The process is introducing more room for bugs to somehow creep in. Damn.

jesse__• 2 years ago

I've had a similar experience several times over the years. Even at companies with no working product that ostensibly wanted to 'move fast and break things'. And I do the same thing; quit and move on. I'm pretty convinced people like that more-or-less can't be reasoned with.

My question is .. is this getting more common as time goes on, or do I just feel like it is..

sarchertech9• 2 years ago

After 20 years of doing this, I’m convinced that required PR reviews aren’t worth the cost.

In the thousands of pull requests I’ve merged across many companies, I have never once had a reviewer catch a major bug (a bug that is severe enough that if discovered after hours, would require an oncall engineer to push a hot fix rather than wait for the normal deployment process to fix it).

I’ve pushed a few major bugs to production, but I’ve never had a PR reviewer catch one.

I’ve had reviewers make excellent suggestions, but it’s almost never anything that really matters. Certainly not worth all the time I’ve spent on the process.

That being said, I’m certainly not against collaboration, but I think required PR reviews aren’t the way to do it.

charlie0• 2 years ago

I'm one of the rare individuals who really tries to review code and leave helpful comments. I've been on the receiving end of really big PRs and can say I understand why you're being told to break things up into smaller chunks.

Most of the devs who submit large PRs just don't have a good grasp of organizing things well enough. I've seen this over and over again and it's due to not spending enough time planning out a feature. There will be exceptions to this, but when devs keep doing it over and over, it's the reviewer's job to reject it and send it back with helpful feedback.

I also understand most people don't like the friction this can create and so you end you with 80% of PRs being rubber stamped and bugs getting into production because the reviewers just give up on trying to make people better devs.

romellem• 2 years ago

mostly useless comments about not having periods at the ends of lines

Oh my god, this sounds like a nightmare. I definitely would not be able to tolerate this for long.

Did you try to get them to change? Were you just not in a senior enough position for anyone to listen?

tdiff2• 2 years ago

As a reviewer I've seen numerous examples of PRs that were basically out of sync with the rest of the project, did not solve the problem they were supposed to solve, or added buggy or unmaintainable code.

Arguments like "but it works in majority of cases" are a way to delegate fixing issues to somebody else later. Unless noone will be using that code at all, in which case it should not be merged either.

nradov3• 2 years ago

It's the same with writing. The best authors occasionally break the rules of grammar and spelling in order to achieve a specific effect. But you have to learn the rules first, and break them only intentionally rather than accidentally. Otherwise your writing ends up as sloppy crap.

(Of course some organizations have coding conventions that are just stupid, but that's a separate issue.)

psychoslave4• 2 years ago

If a function is longer than what I can display on a single screen, it better has to be argumented with very exceptional relevant requirements, which is just as straight forward to judge for anyone with a bit of experience.

raincole• 2 years ago

I've seen a book promoting the idea that methods should not be longer than 5 lines.

Of course now I know these ridiculous statements are from people hardly wrote any code in their lives, but if I'd read them at 18 I would have been totally misled.

quesomaster90007• 2 years ago

Weirdly if you do break everything down into purely functional components it's entirely possible to uncompromisingly make every concept a few lines of code at most, and you will end up with some extremely elegant solutions this way.

You wouldn't be misled at all, only that the path you'd go down is an entirely different one to what you expected it to be.

arzke2• 2 years ago

I know these ridiculous statements are from people hardly wrote any code in their lives

Some people who actually wrote a decent amount of code in their lives are sharing that opinion, so your comment just sounds like an ad-hominem attack.

dboreham2• 2 years ago

You're confusing this with a software development process problem. It's really just good old fashioned psychological abuse.

charles_f• 2 years ago

I like to call these smells, not rules. They're an indication that something might be wrong because you've repeated code, or because your method is too long, or because you have too many parameters. But it might also be a false positive because in this instance it was acceptable to repeat code or have a long method or have many parameters.

Sometimes food smells because it turned bad, and sometimes it's smelly because it's cheese.

dennis_jeeves2• 2 years ago

It almost always comes from a lead or manager who reads too many business books and then cargo cults those books on to the team.

Worse, they behave as though they have profound insights, and put themselves on an intellectually elevated pedestal, which the rest of their ordinary team mortals cannot achieve.

zahlman12• 2 years ago

I'm an experienced developer and I enforce these kinds of rules upon myself without giving it much thought, and I very much prefer the results.

ozim7• 2 years ago

In my experience it usually devs that do that to themselves after reading stuff on the internet and thinking “I want to be a professional and I want to show it to everyone.”

Then rules stay and new people just continue with same silly rules instead of thinking if those are really that useful.

diekhans• 2 years ago

Hard rules are the problem. There is a lot of "it depends."

After over 40 years of programming, I continue to reduce the size of functions and find it easier to write and understand when I return to them. Ten lines are now a personal guideline.

However, a linear function with only tiny loops or conditionals can be easily understood when hundreds of lines are long, but not so much with nested conditionals and loops, where there is natural decomposition into functions.

I observed that the same guidelines became rules problems when test coverage became popular. They soon became metrics rather than tools to think about code and tests. People became reluctant to add sanity check code for things that could should never happen because it brought down code coverage.

asdff2• 2 years ago

There are certainly functions written too cleverly to be apparent how they manage to work at all in a few lines. By my own hand six months ago sometimes. The solution is an unsexy one but always works: write a books worth of comments near that function code that explains absolutely everything and why it was done.

asdff2• 2 years ago

Doing things the right way always introduces a shackle to your ankle. Oh am I to package my functions as discrete packages I call via library name carefully crafted to install into some specific folder structure that I now have to learn and not make mistakes with. Or I can do it “improperly” and just write a function and start using it immediately.

Not everything has to be designed like some standardized mass produced part ready to drop into anything made in the last 40 years. And what is crazy is that even things written to that standard aren’t even compatible and might have very specific dependencies themselves.

devjab• 2 years ago

Every SOLID, Clean Code, DRY and so on are all terrible advice sold by a bunch of people who haven’t worked in software development since before Python was invented. Every one of those principles are continently vague so that people like Uncle Bob can claim that you got it wrong when it doesn’t work for you. Uncle Bob is completely correct though, but maybe the reason you many others got it wrong is because the principles are continently vague. Continently because people like Uncle Bob are consultants who are happy to sell your organisation guidance. I think the biggest nail in the coffin of everything from TDD to Clean Architecture should be that they clearly haven’t worked. It’s been more than 20 years and software is more of a mess than if ever was. If all these “best practices” worked, they would have worked by now.

YAGNI is the only principle I’ve seen consistently work. There are no other mantras that work. Abstractions are almost always terrible but even a rule like “if you rewrite it twice” or whatever people come up with aren’t universal. Sometimes you want an abstraction from the beginning, sometimes you never want to abstract. The key is always to keep the cognitive load as low as possible as the author talks about. The same is true for small functions, and I’ve been guilty of this. It’s much worse to have to go through 90 “go to definition” than just read through one long function.

Yet we still teach these bad best practices to young developers under the pretence that it works and that everything else is technical debt. Hah, technical debt doesn’t really exist. If you have to go back and replace part of your Python code with C because it’s become a bottle neck that means you’ve made it. 95% of all software (and this number is angry man yelling at clouds) will never need to scale because it’ll never get more than a few thousand users at best. Even if your software blows up chances are you won’t know where the future bottle necks will be so stop trying to solve them before you run into them.

GiorgioG4• 2 years ago

Well said.

jrs235• 2 years ago

I think Cognitive Load on a developer includes distractions/interruptions. Constant slack notifications, taps on the shoulder, meetings, etc. increase cognitive load. It's context switching. One only has so much memory and focus, to switch tasks one has additional overhead, thinking and memory/storage demands.

slowmovintarget• 2 years ago

Layering (properly) is used to manage dependencies. You isolate interface logic from business logic with data in between. It lets you evolve the architecture. This is a useful abstraction, not just something academic.

https://www.destroyallsoftware.com/talks/boundaries

mrcsd• 2 years ago

IMO cognative load is much easier to manage when required (human) memory use is less of a factor. In practical terms, this means maximising the locality of reasoning, i.e., having everything you need in front of you to make a decision. One of the reasons I favour rust is precisely because this factor has been a focus in the design.

wcrichton4• 2 years ago

I did my PhD at Stanford about the cognitive aspects of programming, including studies of cognitive load. This article uses pseudoscience to justify folk theories about programming. I would encourage readers to take everything with a grain of salt, and do not wave this article around as a "scientific" justification for anything.

I laid out my objections to the article last year when it first circulated: https://github.com/zakirullin/cognitive-load/issues/22

fforflo• 2 years ago

Congrats on your PhD at Stanford, but some humility has to be part of the scientific process for sure. It looks like a lot of folks called "programmers" agree with the points in the post. If it's such a common experience that should tell you something about the state of affairs.

It's a blog post on the internet. Of course one should take it with a grain of salt. The same applies to any peer-reviewed article on software engineering for example.

Just yesterday, I was watching this interview with Adam Frank [0] one of the parts that stood out was his saying why "Why Science Cannot Ignore Human Experience" (I can't find the exact snippet, but apparently he has a book with the same title.

[0] https://www.youtube.com/watch?v=yhZAXXI83-4

wcrichton4• 2 years ago

I'm not saying that the conclusions in the article are false. As a programmer, I prefer composition to inheritance, too. I'm saying that the justifications are presented using a scientific term of art (cognitive load), but the scientific evidence regarding cognitive load isn't sufficient to justify these claims.

GiorgioG4• 2 years ago

Where was the word “scientific” mentioned in the article? I don’t think you were the target reader they had in mind when the author wrote this. I’ve been programming since 1986, and this article resonates with my experience. More abstractions, layers, and so on requires my brain to have to keep track of more shit which takes away from doing the work that brought me to work on that bit of code (bug fix, feature work, debugging, etc.)

We’re very proud of you and the hard work you did to earn your PhD, now please stop trotting it out.

wcrichton4• 2 years ago

The article is attempting to use a scientific term of art, "cognitive load", to justify claims about programming. Those claim cannot be justified given the existing evidence about cognitive load. As I explain in my linked response, I nonetheless agree with many of the claims, but they're best understood as folk theories than scientific theories.

And I don't think condescension will make this a productive discussion!

LAC-Tech4• 2 years ago

Not knowledgeable enough to weigh in here, I just think it's very cool that 1) the authors blog was in public source control and 2) you made a polite github issue with your criticisms and 3) it wasn't deleted.

Tainnor6• 2 years ago

Thanks for sharing your knowledge and please ignore some of the other comments. HN is a place for "intellectual curiosity", but for some reason it always attracts its fair share of anti-intellectualism. Debating what cognitive load actually is is very relevant to the topic at hand.

FWIW, I can't speak to the science of it but as a programmer I even disagree with many of the conclusions in the article, such as that advanced language features are bad because they increase mental load.

sgt• 2 years ago

  AdminController extends UserController extends GuestController extends BaseController

That's nothing... Java enterprise programmer enters the chat

creer• 2 years ago

Too many small methods, classes or modules Method, class and module are interchangeable in this context

Class, method, functions are NOT the only way to manage cognitive load. Other ways work well for thinking developers:

Formatting - such as a longer lines and lining up things to highlight identical and different bits.

Commenting - What a concept?! using comments to make things more clear.

Syntactic sugar, moderate use of DSL features, macros... - Is this sometimes the right way?

But yeah, if your tool or style guide or programming language even, imposes doing everything through the object system or functions, then someone clearly knew better. And reduced your cognitive load by taking away your choices /s.

svilen_dobrev• 2 years ago

Involve junior developers in architecture reviews. They will help you to identify the mentally demanding areas.

This.

And also, a mantra of my own: Listen carefully to any newcomer in the team/company in first 1-3 weeks, until s/he gets accustomed (and/or stop paying attention to somewhat uneasy stuff). They will tell you all things that are, if not wrong, at least weird.

tantalor• 2 years ago

Junior developers probably won't say anything, because they are used to not understanding code, and they are not going to second guess the more-experienced author.

jstummbillig• 2 years ago

It's definitely on the senior to prompt the junior appropriately. But when you do, they will.

ben_w2• 2 years ago

Aye, but the joiners may need prompting as well as getting listened to.

In each place where I've seen something wildly wrong, the problem has been clear in the first few weeks — sometimes even in the first few days* — but I always start with the assumption that if I disagree with someone who has been at it for years, they've probably got good reasons for the stuff that surprises me.

Unfortunately I'm not very convincing: when I do finally feel confident enough to raise stuff, quite often they do indeed have reasons… bad reasons that ultimately prove to be fatal or near-fatal flaws to their business plans, but the issues only seldom get fixed once I raise them.

* one case where the problem was visible in the interview, but I was too young and naive so I disregarded what I witnessed, and I regretted it.

epolanski6• 2 years ago

I second this, but one should also be extremely wary of newcomers feedback and try to understand their nature.

Some people are extremely resistant to new ideas, some might be simply lazy, some can't be bothered to read documentations, etc.

Spotting the real person behind the feedback is crucial and often those people need to be fired fast.

I myself tend to be lazy when it comes to learn new stuff/patterns, especially when I am in the middle of having to progress a project so my own feedback may be more of a frustration for my inability to progress due to having to understand first a, b, c and d which may take considerable time and pain for something I can do in an old way in few minutes.

bob1029• 2 years ago

Types of cognitive load - Extrinsic/Intrinsic

This neatly mirrors the central ideas presented in Out of the Tar Pit [0], which defines accidental and essential complexity.

Reading this paper was probably one of the biggest career unlocks for me. You really can win ~the entire game if you stay focused on the schema and keep in touch with the customer often enough to ensure that it makes sense to them over time.

OOTP presents a functional-relational programming approach, but you really just need the relational part to manage the complexity of the domain. Being able to say that one domain type is relevant to another domain type, but only by way of a certain set of attributes (in a 3rd domain type - join table), is an unbelievably powerful tool when used with discipline. This is how you can directly represent messy real world things like circular dependencies. Modern SQL dialects provide recursive CTEs which were intended to query these implied graphs.

Over time, my experience has evolved into "let's do as much within the RDBMS as we possibly can". LINQ & friends are certainly nice to have if you need to build a fancy ETL pipeline that interfaces with some non-SQL target, but they'll never beat a simple merge statement in brevity or performance if the source & target of the information is ultimately within the same DB scope. I find myself spending more time in the SQL tools (and Excel) than I do in the various code tools.

[0] https://curtclifton.net/papers/MoseleyMarks06a.pdf

jmyeet3• 2 years ago

I have an issue with complex conditions with or without local variable labels for readability. You really shouldn't have them at all.

At one time, they used to teach that functions should have one entry-point (this is typically a non-issue but can come up with assembly code) and one exit-point. Instead of a complex condition, I much prefer just early returns ie:

    // what's going on 1
    if (condition1 || condition2) {
      return;
    }

    // what's going on 2
    if (condition3 && condition4) {
      return;
    }

    // what's going on 3
    if (condition5) {
      return;
    }

    // do the thing
    return;

Aeolos• 2 years ago

I prefer this style for languages that have either a GC or scoped resource management (eg RAII).

However, I think the single exit point holds merit for C, where an early return can easily and silently cause a resource leak. (Unless you use compiler-specific extensions, or enforce rust-style resource ownership, which is really hard without compiler support.)

meowface• 2 years ago

I've sometimes seen people attack early returns and I've never understood it. To me they make things so much cleaner that it seems like common sense.

ziml772• 2 years ago

I think it makes some sense when you are working in a language that provides no mechanisms for automatically calling cleanup functions on exiting a scope (i.e. C). But otherwise, early returns are much clearer in most cases.

worik• 2 years ago

Interesting. I am in agreement

But not one word about comments, and only one about naming.

Useful comments go a long way to lessening cognitive load

Good names are mnemonics, not documentation

I have worked on code bases with zero comments on the purposes of functions, and names like "next()"

And I've worked with programmers who name things like "next_stage_after_numeric_input"

K0nserv10• 2 years ago

I've been thinking about the notion of "reasoning locally" recently. Enabling local reasoning is the only way to scale software development past some number of lines or complexity. When reasoning locally, one only needs to understand a small subset, hundreds of lines, to safely make changes in programs comprising millions.

I find types helps massively with this. A function with well-constrained inputs and outputs is easy to reason about. One does not have to look at other code to do it. However, programs that leverage types effectively are sometimes construed as having high cognitive load, when it in fact they have low load. For example a type like `Option<HashSet<UserId>>` carries a lot of information(has low load): we might not have a set of user ids, but if we do they are unique.

The discourse around small functions and the clean code guidelines is fascinating. The complaint is usually, as in this post, that having to go read all the small functions adds cognitive load and makes reading the code harder. Proponents of small functions argue that you don't have to read more than the signature and name of a function to understand what it does; it's obvious what a function called last that takes a list and returns an optional value does. If someone feels compelled to read every function either the functions are poor abstractions or the reader has trust issues, which may be warranted. Of course, all abstractions are leaky, but perhaps some initial trust in `last` is warranted.

0xFACEFEED• 2 years ago

A function with well-constrained inputs and outputs is easy to reason about.

It's quite easy to imagine a well factored codebase where all things are neatly separated. If you've written something a thousand times, like user authentication, then you can plan out exactly how you want to separate everything. But user authentication isn't where things get messy.

The messy stuff is where the real world concepts need to be transformed into code. Where just the concepts need to be whiteboarded and explained because they're unintuitive and confusing. Then these unintuitive and confusing concepts need to somehow described to the computer.

Oh, and it needs to be fast. So not only do you need to model an unintuitive and confusing concept - you also need to write it in a convoluted way because, for various annoying reasons, that's what performs best on the computer.

Oh, and in 6 months the unintuitive and confusing concept needs to be completely changed into - surprise, surprise - a completely different but equally unintuitive and confusing concept.

Oh, and you can't rewrite everything because there isn't enough time or budget to do that. You have to minimally change the current uintuitive and confusing thing so that it works like the new unintuitive and confusing thing is supposed to work.

Oh, and the original author doesn't work here anymore so no one's here to explain the original code's intent.

haliskerbas• 2 years ago

This puts things really well. I’ll add into it that between the first white boarding session and the first working MVP there’ll be plenty of stakeholders who change their mind, find new info, or ask for updates that may break the original plan

ilvez• 2 years ago

Plus to everything said. It's an everyday life of "maintainer", picking the next battle to pick the best way to avoid sinking deeper and defending the story that exactly "this" is the next refactoring project. All that while balancing different factors as you mention to actually believe oneself, because there are countless of paths..

mgkimsal• 2 years ago

Oh, and in 6 months the unintuitive and confusing concept needs to be completely changed into - surprise, surprise - a completely different but equally unintuitive and confusing concept.

But you have to keep the old way of working exactly the same, and the data can't change, but also needs to work in the new version as well. Actually show someone there's two modes, and offer to migrate their data to version 2? No way - that's confusing! Show different UI in different areas with the same data that behaves differently based on ... undisclosed-to-the-user criteria. That will be far less confusing.

lukan• 2 years ago

It can be done. Sometimes.

I am so proud and happy, when I can make a seemingly complicated change quickly, because the architecture was well designed and everthing neatly seperated.

Most of the time though, it is exactly like you described. Or randalls good code comic:

https://xkcd.com/844/

Allmost too painful to be funny, when you know the pain is avoidable in theory.

Still, it should not be an excuse to be lazy and just write bad code by default. Developing the habit of making everything as clean, structured and clear as possible allways pays of. Especially if that code, that was supposed to be a quick and dirty throw away code experiment somehow ended up being used and 2 years later you suddenly need to debug it. (I just experienced that joy)

justinram11• 2 years ago

Oh, and the original author doesn't work here anymore so no one's here to explain the original code's intent.

To be fair, even if I still work there I don't know that I'm going to be of much help 6 months later other than a "oh yeah, I remember that had some weird business requirements"

dogcomplex• 2 years ago

Sounds like a bunch of excellent excuses why code is not typically well factored. But that all just seems to make it more evident that the ideal format should be more well-factored.

mcdeltat2• 2 years ago

IMO the fact that code tends to become hard over time in the real world, is even more reason to lower cognitive load. Because cognitive load is related to complexity. Things like inheritance make it far too easy to end up with spaghetti. So if it's not providing significant benefit, god damn don't do it in the first place (like the article mentions).

chii• 2 years ago

Where just the concepts need to be whiteboarded and explained because they're unintuitive and confusing.

they're intuitive to somebody - just not the software engineer. This simply means there's some domain expertise which isn't available to the engineer.

rtpg3• 2 years ago

I mean really nobody wants an app that is slow, hard to refactor, with confusing business logic etc. Everyone wants good proporties.

So then you get into what you’re good at. Maybe you’re good at modeling business logic (even confusing ones!). Maybe you’re good at writing code that is easy to refactor.

Maybe you’re good at getting stuff right the first time. Maybe you’re good at quickly fixing issues.

You can lean into what you’re good at to get the most bang for your buck. But you probably still have some sort of minimum standards for the whole thing. Just gotta decide what that looks like.

namaria7• 2 years ago

you also need to write it in a convoluted way because, for various annoying reasons, that's what performs best on the computer.

That's nothing to do with hardware. The various annoying reasons are not set in stone or laws of physics. They are merely the path dependency of decades of prioritizing shipping soon because money.

larsrc5• 2 years ago

Oh, and there's massive use of aspect-oriented programming, the least local paradigm ever!

SkyBelow2• 2 years ago

It's quite easy to imagine a well factored codebase where all things are neatly separated.

If one is always implementing new code bases that they keep well factored, they should count their blessings. I think being informed about cognitive load in code bases is still very important for all the times we aren't so blessed. I've inherited applications that use global scope and it is a nightmare to reason though. Where possible I improve it and reduce global scope, but that is not always an option and is only possible after I have reasoned enough about the global scope to feel I can isolate it. As such, letting others know of the costs is helpful to both reduce it from happening and to convince stakeholders of the importance of fixing it after it has happened and accounting for the extra costs it causes until it is fixed.

The messy stuff is where the real world concepts need to be transformed into code.

I also agree this can be a messy place, and on a new project, it is messy even when the code is clean because there is effectively a business logic/process code base you are inheriting and turning into an application. I think many of the lessons carry over well as I have seen an issue with global scope in business processes that cause many of the same issues as in code bases. When very different business processes end up converging into one before splitting again, there is often extra cognitive load created in trying to combine them. A single instance really isn't bad, much like how a single global variable isn't bad, but this is an anti-pattern that is used over and over again.

One helpful tool is working ones way up to the point of having enough political power and earned enough respect for their designs to have suggestions of refactoring business processes be taken into serious consideration (one also has to have enough business acumen to know when such a suggestion is reasonable).

the original author doesn't work here anymore so no one's here to explain the original code's intent.

I fight for comments that tell me why a certain decision is made in the code. The code tells me what it is doing, and domain knowledge will tell most of why it is doing the things expected, but anytime the code deviates from doing what one would normally expect to be done in the domain, telling me why it deviated from expected behavior is very important for when someone is back here reading it 5+ years later when no one is left from the original project. Some will suggest putting it in documentation, but I find that the only documentation with any chance of being maintained or even kept is the documentation built into the code.

jimbokun• 2 years ago

In my experience, the more convoluted code is more likely to have performance issues.

yearolinuxdsktp2• 2 years ago

Nothing about computers is intuitive. Not even using a mouse.

A late-breaking change is a business advantage—-learn how to roll with them.

motorest2• 2 years ago

I've been thinking about the notion of "reasoning locally" recently. Enabling local reasoning is the only way to scale software development past some number of lines or complexity. When reasoning locally, one only needs to understand a small subset, hundreds of lines, to safely make changes in programs comprising millions.

That was supposedly the main trait of object-oriented programming. Personally that was how it was taught to me: the whole point of encapsulation and information hiding is to ensure developers can "reason locally", and thus be able to develop more complex projects by containing complexity to specific units of execution.

Half of SOLID principles also push for that. The main benefit of Liskov's substitution principle is ensure developers don't need to dig into each and every concrete implementation to be able to reason locally about the code.

On top of that, there are a multitude of principles and rules of thumb that also enforce that trait. For example, declaring variables right before they are used the first time. Don't Repeat Yourself to avoid parsing multiple implementations of the same routine. Write Everything Twice to avoid premature abstractions and tightly coupling units of execution that are actually completely independent, etc etc etc.

Heck, even modularity, layered software architectures, and even microservices are used to allow developers to reason locally.

In fact, is there any software engineering principle that isn't pushing for limiting complexity and allowing developers to reason locally?

hiAndrewQuinn2• 2 years ago

In theory, you could design a parallel set of software engineering best practices which emphasize long-term memory of the codebase over short-term ability to leaf through and understand it. I guess that would be "reasoning nonlocally" in a useful sense.

In practice I think the only time this would be seen as a potentially good thing by most devs is if it was happening in heavily optimized code.

708145_• 2 years ago

The main benefit of Liskov's substitution principle is ensure developers don't need to dig into each and every concrete implementation to be able to reason locally about the code.

Yeah, but doesn't help in this context (enable local reasoning) if the objects passed around have too much magic or are mutated all over the place. The enterprise OOP from 2010s was a clusterfuck full of unexpected side effects.

sunshowers7• 2 years ago

Encapsulation is the good part of object-oriented programming for precisely this reason, and most serious software development relies heavily on encapsulation. What's bad about OOP is inheritance.

Microservices (in the sense of small services) are interesting because they are good at providing independent failure domains, but add the complexity of network calls to what would otherwise be a simple function call. I think the correct size of service is the largest you can get away with that fits into your available hardware and doesn't compromise on resilience. Within a service, use things like encapsulation.

6510• 2 years ago

Out of curiosity I sometimes rewrite things as spaghetti (if functions are short and aren't called frequently) or using globals (if multiple functions have to many params) it usually doesn't look better and when it does it usually doesn't stay that way for very long. In the very few remaining cases I'm quite happy with it. It does help me think about what is going on.

KronisLV2• 2 years ago

In fact, is there any software engineering principle that isn't pushing for limiting complexity and allowing developers to reason locally?

Both DRY and SOLID lead to codebases that can be worse in this respect.

DRY and SRP limit what will be done in a single method or class, meaning that both the logic will eventually be strewn across the codebase, as well as any changes to that will need to take all of the pieces using the extracted logic into account. Sometimes it makes sense to have something like common services, helper and utility classes, but those can be in direct opposition to local reasoning for any non-trivial logic.

Same for polymorphism and inheritance in general, where you suddenly have to consider a whole class structure (and any logic that might be buried in there) vs the immediate bits of code that you’re working with.

Those might be considered decent enough practices to at least consider, but in practice they will lead to a lot of jumping around the codebase, same for any levels of abstraction (resource/controller, service, mappers, Dto/repository, …) and design patterns.

DarkNova62• 2 years ago

100% agree and this not only concerns readability. The concept of "locality" turns out to be a fairly universal concept, which applies to human processes just as much as technical ones. Side-effects are the root of all evil.

You don't see a waiter taking orders from 1 person on a table, but rather go to a table and get orders from everybody sitting there.

And as for large methods, I find that they can be broken into smaller once just fine as long as you keep them side-effect free. Give them a clear name, a clear return value and now you have a good model for the underlying problem you are solving. Looking up the actual definition is just looking at implementation details.

LtWorf2• 2 years ago

I've seen functions called getValue() that were actually creating files on disk and writing stuff.

Also, even if the function actually does what advertised, I've seen functions that go 4-5 levels deep where the outer functions are just abstracting optional parameters. So to avoid exposing 3 or 4 parameters, tens of functions are created instead.

I think you do have a point but ideas get abused a lot.

bb88• 2 years ago

The larger problem are things that have global effect: databases, caches, files, static memory, etc. Or protocols between different systems. These are hard to abstract away, usually because of shared state.

mrkeen6• 2 years ago

Weird, I read that between the lines of parent's post. Of course local reasoning precludes global effects.

peterlada• 2 years ago

There is an issue of reading a code that is written by somebody else. If it's not in a common style, the cognitive load of parsing how it's done is an overhead.

The reason I used to hate Perl was around this, everyone had a unique way of using Perl and it had many ways to do the same thing.

The reason I dislike functional programming is around the same, you can skin the cat 5 ways, then all 5 engineers will pick a different way of writing that in Typescript.

The reason I like Python more is that all experienced engineers will eventually gravitate towards the idea of Pythonic notion and I've had colleagues whose code looked identical to how I'd have written it.

mrkeen6• 2 years ago

Python 2, Python 3? Types or no types?

sunshowers7• 2 years ago

This is absolutely the right way to think about things.

I like thinking about local reasoning in terms of (borrowing from Ed Page) "units of controversy". For example, I like using newtypes for identifiers, because "what strings are permitted to be identifiers" is a unit of controversy.

nevi-me2• 2 years ago

If someone feels compelled to read every function either the functions are poor abstractions or the reader has trust issues, which may be warranted.

I joined a company with great code and architecture for 3 months last year. They deal with remittances and payments.

Their architecture leads are very clued up, and I observed that they spent a lot of quality time figuring out their architecture and improvements, continuously. They'd do a lot of refactors for all the various teams, and the cadence of feature development and release was quite impressive.

In that period though, I and another long-standing colleague made a few errors that cost the company a lot of money, like an automated system duplicating payments to users for a few hours until we noticed it.

Part of their architectural decision was to use small functions to encapsulate logic, and great care and code review was put into naming functions appropriately (though they were comment averse).

The mistakes we committed, were because we trusted that those functions did what they said they did correctly. After all, they've also been unit tested, and there's also integration tests.

If it weren't for the fortitude of the project manager (great guy hey) in firmly believing in collective responsibility if there's no malice, I'd probably have been fired after a few weeks (I left for a higher offer elsewhere).

---

So the part about trust issues resonates well with me. As a team we made the decision that we shouldn't always trust existing code, and the weeks thereafter had much higher cognitive load.

avg_dev2• 2 years ago

That sounds like a very difficult situation. Would you be willing to elaborate on what kinds of bugs lay in the pre-existing functions? Was some sort of operation that was supposed to be idempotent (“if you call it with these unique parameters over and over, it will be the same as if you only called it once”) not so? I am trying to imagine what went wrong here. A tough situation, must have been quite painful. How serious were the consequences? If you don’t feel comfortable answering that is okay.

SkyBelow2• 2 years ago

The mistakes we committed, were because we trusted that those functions did what they said they did correctly. After all, they've also been unit tested, and there's also integration tests.

As it is stated, I don't see where it is your mistake. You should be able to trust things do what they say, and there should be integration testing that happens which adds the appropriate amount of distrust and verification. Even with adequate unit testing, you normally inject the dependencies so it wouldn't be caught.

This seems an issue caused by two problems, inadequate integration testing and bugs in the original function, neither of which are your fault.

Building a sixth sense of when to distrust certain code is something you see from more experienced developers at a company, but you were new so there is no reason to expect you to have it (and the system for making code changes shouldn't depend upon such intuition anyways).

barrkel• 2 years ago

Function names aren't wholly distinct from comments. They suffer from the same problems as comments - they can go stale and no longer reflect the code they're naming.

layer83• 2 years ago

Functions generally need to be documented, especially if there are any gotchas not obvious from the function signature. And one should always read the documentation. Good names are for discovery and recollection, and for the call-site code to be more intelligible, but they don’t replace having a specification of the function’s interface contract, and client code properly taking it into account.

casenmgreen3• 2 years ago

I may be wrong, but my view of software is : you have functions, and you have the order in which functions are called. Any given function is straightforward enough, if you define its function clearly and keep it small enough - both of which can reasonably be done. Then we have the problem, which is the main problem, of the order in which functions are called. For this, I use a state machine. Write out the state machine, in full, in text, and then implement it directly, one function per state, one function per state transition.

The SM design doc is the documentation of the order of function calling, it is exhaustive and correct, and allows for straightforward changes in future (at least, as straightforward as possible - it is always a challenge to make changes).

euph0ria5• 2 years ago

Would love to understand this better. Is there any example you could point to?

jreback• 2 years ago

Re: trust issues...I'd argue this is the purpose of automated tests. I think tests are too often left out of architectural discussions as if they are some additional artifact that gets created separately from the running software. The core / foundational / heavily reused parts of the architecture should have the most tests and ensure the consumers of those parts has no trust issues!

K0nserv10• 2 years ago

Tests are good but moving left by lifting invariants into the type system is better.

Compare

   fn send_email(addr: &str, subject: &str, body: &str) -> Result<()>

    fn send_email(add: &EmailAddr, subject: &str, body: &str) -> Result<()>

In the second case, the edge cases of an empty or invalid email address don't need to be tested, they are statically impossible.

mattmcknight3• 2 years ago

Types? "Option<HashSet<UserId>>" means almost nothing to me. A well defined domain model should indicate what that structure represents.

bbkane• 2 years ago

Even that means a lot more than `{}`, who's tortured journeys I have to painstakingly take notes om in the source code while I wonder what the heck happened to produce the stack trace...

jbggs• 2 years ago

it seems like you're just not familiar with the domains defined by those types, or at least the names used here

anon-39882• 2 years ago

A well defined domain model should indicate what that structure represents.

"Should", but does it? If a function returns Option<HashSet<UserId>> I know immediately that this function may or may not return the set, and if it does return the set, they are unique.

This is a fact of the program, I may not know "why" or "when" it does what. But as a caller, I can guarantee that I handled every possible code path. I wouldn't get surprised later one because, apparently, this thing can throw an exception, so my lock didn't get released.

mcdeltat2• 2 years ago

In regards to small functions, I think an important - but not often mentioned - aspect is shared assumptions. You can have many small functions with garbage abstractions that each implictly rely on the behaviour of each other - therefore the cognitive load is high. Or, you can have many small functions which are truly well-contained, in which case you may well need not read the implementation. Far too much code falls into the former scenario, IMO.

holri4• 2 years ago

I do not agree that typing leads to less cognitive load. Typing often leads to more and more complicated code. Dynamically typed code is often shorter and more compact. If dynamically typed code is well written, its function, inputs and outputs are clear and obvious. Clear and easy to understand code is not primarily a matter of typed or not typed code, it is a matter of a great programmer or a poor one.

mirekrusin• 2 years ago

This is true at smaller scales and flips over on larger scales (larger codebase, dependencies, team/teams sizes).

K0nserv10• 2 years ago

Statically typed code definitely requires more effort to read, but this is not cognitive load. Cognitive load is about how much working memory is required. Statically typed code requires less cognitive load because some of the remembering is outsourced to the source code.

Statically typed code can lead to more complicated code; it can also accurately reflect the complexity inherent in the problem.

com2kid2• 2 years ago

There is a function. It takes in 4 parameters. One of them is called ID

Is ID a string, a number, a GUID? Better check the usage within the function.

Oh, the declaration is `id: number`

Mystery solved.

Even better if the language supports subtyping so it is something like id: userID and userID is a subtype of number.

dataflow• 2 years ago

Absolutely with you on the idea in the abstract, but the problem you run into in practice is that enabling local reasoning (~O(1)-time reading) often comes at the cost of making global changes (say, ~O(n)-time writing in the worst case, where n is the call hierarchy size) to the codebase. Or to put it another way, the problem isn't so much attaining local readability but maintaining it -- it imposes a real cost on maintenance. The cost is often worth it, but not always.

Concrete toy examples help here, so let me just give a straight code example.

Say you have the following interface:

  void foo(void on_completed());

  void callback();

  void bar(int n)
  {
    foo(callback);
  }

Now let's say you want to pass n to your callback. (And before you object that you'd have the foresight to enable that right in the beginning because this is obvious -- that's missing the point, this is just a toy example to make the problem obvious. The whole point here is you found a deficiency in what data you're allowed to pass somewhere, and you're trying to fix it during maintenance. "Don't make mistakes" is not a strategy.)

So the question is: what do you do?

You have two options:

1. Modify foo()'s implementation (if you even can! if it's opaque third party code, you're already out of luck) to accept data (state/context) along with the callback, and plumb that context through everywhere in the call hierarchy.

2. Just embed n in a global or thread-local variable somewhere and retrieve it later, with appropriate locking, etc. if need be.

So... which one do you do?

Option #1 is a massive undertaking. Not only is it an O(n) changes for a call hierarchy of size n, but foo() might have to do a lot of extra work now -- for example, if it previously used a lock-free queue to store the callback, now it might lose performance as it might not be able to do everything atomically. etc.

Option #2 only results in 3 modifications, completely independently from the rest of the code: one in bar(), one for the global, and one in the callback.

Of course the benefit of #1 here is that option #1 allows local reasoning when reading the code later, whereas option #2 is spooky action at a distance: it's no longer obvious that callback() expects a global to be set. But the downside is that now you might need to spend several more hours or days or weeks to make it work -- depending on how much code you need to modify, which teams need to approve your changes, and how likely you are to hit obstacles.

So, congratulations, you just took a week to write something that could've taken half an hour. Was it worth it?

I mean, probably yes, if maintenance is a rare event for you. But what if you have to do it frequently? Is it actually worth it to your business to make (say) 20% of your work take 10-100x as long?

I mean, maybe still it is in a lot of cases. I'm not here to give answers, I absolutely agree local reasoning is important. I certainly am a zealot for local reasoning myself. But I've also come to realize that achieving niceness is quite a different beast from maintaining it, and I ~practically never see people try to give realistic quantified assessments of the costs when trying to give advice on how to maintain a codebase.

o_nate2• 2 years ago

Add a global variable? Let's not go there, please. Anything would be better than that. In this case I would bite the bullet and change the signature, but rather than just adding the one additional parameter, I would add some kind of object that I could extend later without breaking the call signature, since if the issue came up once, it's more likely to come up again.

vacuity4• 2 years ago

Initial implementation and maintenance need to keep design in mind, and there should be more clarity around responsibility and costs of particular designs and how flexible the client is with the design at a given point in time. It's an engineering process and requires coordination.

ajuc4• 2 years ago

Last is something that is embarrassingly extractable, which makes it a bad example (you shouldn't write that function anyway in 99% of cases - surely someone wrote it already in stdlib of your language).

It's like taking "list.map(x -> x*x)" as a proof that parallelism is easy.

Most code is not embarrassingly extractable (or at least not at granularity of 3 lines long methods).

movpasd• 2 years ago

I feel that one big way in which engineers talk past each other is in assuming that code quality is an inherent property of the code itself. The code is meaningless without human (and computer) interpretation. Therefore, the quality of code is a function of the relationship between that code and its social context.

Cognitive load is contextual. `Option<HashSet<UserId>>` is readable to someone knowledgeable in the language (`Option`, `HashSet`) and in the system (meaning of `UserId` -- the name suggests it's an integer or GUID newtype, but do we know that for sure? Perhaps it borrows conventions from a legacy system and so has more string-like semantics? Maybe users belong to groups, and the group ID is considered part of the user ID -- or perhaps to uniquely identify a user, you need both the group and user IDs together?).

What is the cognitive load of `Callable[[LogRecord, SystemDesc], int]`? Perhaps in context, `SystemDesc` is very obvious, or perhaps not. With surrounding documentation, maybe it is clear what the `int` is supposed to mean, or maybe it would be best served wrapped in a newtype. Maybe your function takes ten different `Callable`s and it would be better pulled out into an polymorphic type. But maybe your language makes that awkward or difficult. Or maybe your function is a library export, or even if it isn't, it's used in too many places to make refactoring worthwhile right now.

I also quite like newtypes for indicating pragmatics, but it is also a contextually-dependent trade-off. You may make calls to your module more obvious to read, but you also expand the module's surface area. That means more things for people writing client code to understand, and more points of failure in case of changes (coupling). In the end, it seems to me that it is less important whether you use a newtype or not, and more important to be consistent.

In fact, this very trade-off -- readability versus surface area -- is at the heart of the "small vs large functions" debate. More smaller functions, and you push your complexity out into the interfaces and relationships between functions. Fewer large functions, and the complexity is internalised inside the functions.

To me, function size is less the deciding factor [0], but rather whether your interfaces are real, _conceptually_ clean joints of your solution. We have to think at a system level. Interfaces hide complexity, but only if the system as a whole ends up easier to reason about and easier to change. You pay a cost for both interface (surface area) and implementation (volume). There should be a happy middle.

---

[0] Also because size is often a deceptively poor indicator of implementation complexity in the first place, especially when mathematical expressions are involved. Mathematical expressions are fantastic exactly because they syntactically condense complexity, but it means very little syntactic redundancy, and so they seem to be magnets for typos and oversights.

TZubiri2• 2 years ago

I've been thinking about the notion of "reasoning locally" recently. Enabling local reasoning is the only way to scale software development past some number of lines or complexity. When reasoning locally, one only needs to understand a small subset, hundreds of lines, to safely make changes in programs comprising millions.

Have you never heard of the word of our lord and saviour oop, or functions? It's called encapsulation.

You might have learned it through prog langs as it is an embedded ideal

K0nserv10• 2 years ago

As another sibling comment pointed out there are many tools that enable local reasoning, encapsulation is one such tool.

I'm not claiming the idea is novel, just that I haven't encountered a name for it before.

konschubert• 2 years ago

The first step for allowing local reasoning is to break your product into independent subdomains that are as independent as possible.

For a software company, this means crafting the product ownership of your team such that the teams can act as independently as possible.

This is where most companies already fail.

Once this has been achieved, you can follow this pattern on smaller and smaller scales down to individual functions in your code.

larsrc5• 2 years ago

If someone feels compelled to read every function either the functions are poor abstractions or the reader has trust issues, which may be warranted.

Or it's open source and the authors were very much into Use The Source, Luke!

tdiff2• 2 years ago

Proponents of small functions argue that you don't have to read more than the signature and name of a function to understand what it does; it's obvious what a function called last that takes a list and returns an optional value does.

It's also interesting that in comment to the same article many people argue against PR process. I hardly see how else that level of discipline required not to undermine trust in names of small methods can be maintained for any team with more than 3 developers.

blago• 2 years ago

Proponents of small functions argue that you don't have to read more than the signature and name of a function to understand what it does;

Although this is often the case, the style of the program can change things significantly. Here are a few, not so uncommon, examples where it starts to break down:

1. When you’re crafting algorithms, you might try to keep code blocks brief, but coming up with precise, descriptive names for each 50-line snippet can be hard. Especially if the average developer might not even fully understand the textbook chapter behind it.

2. At some point you have to build higher than "removeLastElementFromArray"-type of functions. You are not going to get very far skimming domain-specific function names if don’t have any background in that area.

More examples exist, but these two illustrate the point.

K0nserv10• 2 years ago

Both examples stem from not understanding the problem well enough I think. My best work is done when I first write a throwaway spaghetti solution to the problem. Only through this endeavour do I understand the problem well enough to effectively decompose the solution.

meehai• 2 years ago

At work we have a pretty big Python monorepo. The way we scale it is by having many standalone CLI mini apps ( about 80) atm with most of them outputting json/parquet in GCS or bigquery tables. Inputs are the same.

I insisted a lot on this unix (ish as it's not pipes) philosophy. It paid off so far.

We can test each cli app as well as make broader integration tests.

cle• 2 years ago

I find types helps massively with this. A function with well-constrained inputs and outputs is easy to reason about. One does not have to look at other code to do it. However, programs that leverage types effectively are sometimes construed as having high cognitive load, when it in fact they have low load. For example a type like `Option<HashSet<UserId>>` carries a lot of information(has low load): we might not have a set of user ids, but if we do they are unique.

They sometimes help. But I think it's deeper than this. A function with inputs and outputs that are well-constrained with very abstract, complex types is still hard to reason about, unless you're used to those abstractions.

I think it's more accurate to say that something is "easy to reason about" if its level of abstraction "closely matches" the level of abstraction your brain is comfortable with / used to. This can vary dramatically between people, depending on their background, experience, culture, etc.

I could describe the Option<HashSet<UserId>> type in terms of functors and applicatives and monads, and though it would describe exactly the same set of valid values, it has a much higher cognitive load for most people.

However, programs that leverage types effectively are sometimes construed as having high cognitive load, when it in fact they have low load.

Cognitive load is an individual experience. If someone "construes" something as having high cognitive load, then it does! (For them). We should be writing programs that minimize cognitive load for the set of programmers who we want to be able to interact w/ the code. That means the abstractions need to sufficiently match what they are comfortable with.

It's also fine to say "sorry, this code was not intended to have low cognitive load for you".

mithametacs• 2 years ago

Not everything is a functional program though and side effects are important. Types can’t* represent this.

*Not for practical programs

jonahx• 2 years ago

Proponents of small functions argue that you don't have to read more than the signature and name of a function to understand what it does; it's obvious what a function called last that takes a list and returns an optional value does.

I used to be one of those proponents, and have done a 180.

The problems are:

1. The names are never as self-evident as you think, even if you take great care with them.

2. Simply having so many names is an impediment in itself.

The better way:

Only break things up when you need to do. This means the "pieces" of the system correspond to the things you care about and are likely to change. You'll know where to look.

When you actually need an abstraction to share code between parts of the system, create it then.

hinkley• 2 years ago

Types are somewhat a different dimension. Sort of the classic 1 dimensional argument about a 2 dimensional problem domain. Which quadrant you’re talking about alters whether the arguments support reality or argue with it.

If understanding a block of code requires knowing a concept that the team feels everyone should know anyway, then it’s not such an imposition. If the code invites you to learn that concept, so much the better. The code is “discoverable” - it invites you to learn more. If the concept is incidental to the problem and/or the team is objectively wrong in their opinion, then you have tribal knowledge that is encroaching on the problem at hand. And whether it’s discoverable or not is neither here nor there. Because understanding the code requires knowing lots of other things, which means either memorization, or juggling more concepts than comfortably fit in short term memory - cognitive overload.

You know you’ve blown past this point when you finally trace the source of a bad piece of data but cannot remember why you were looking for it in the first place.

I’m hoping the problem of cognitive load gets more attention in the near future. We are overdue. But aside from people YouTubing code reviews, I’m still unclear what sorts of actionable metrics or feedback will win out in this arena. Maybe expanding code complexity to encompass the complexity of acquiring the values used in the code, not just the local data flow.

papaver• 2 years ago

a lot of good points but i feel like one of the biggest i've learned is missing...

leaning toward functional techniques has probably had the biggest impact on my productivity in the last 10 years. some of the highest cognitive load in code comes from storing the current state of objects in ones limited memory. removing state and working with transparent functions completely changes the game. once i write a function that i trust does its job i can replace its implementation with its name in my memory and move on to the next one.

menotyou• 2 years ago

Before OOP became popular the usage of global variables was discouraged in procedural languages because it was the cause of many bugs and errors.

In OOP global state variables were renamed to instance variables and are now widely used. The problem why it was discouraged beforehand did not went away by renaming but is now spread all over the place.

markus_zhang• 2 years ago

I don't program professionally (I work as a DE but I don't consider it as a serious programming venue) so the No. 1 issue while reading medium-large source code is abstraction -- programming patterns.

I hope it improves whence I write an implementation myself.

jeremydeanlakey2• 2 years ago

The central idea around cognitive load is very good, central to writing good code.

But it's deeply mistaken to oppose smaller (or more correctly: simpler) classes/functions and layered architecture.

Layered architecture and simple (mostly small) classes and methods are critical to light cognitive load.

e.g. You should not be handling database functionality in your service classes, nor should you be doing business logic in your controllers. These different kinds of logic are very different, require different kinds of knowledge. Combining them _increases_ cognitive load, not decreases.

It's not mainly about swapping out dependencies (although this is an important benefit), it's about doing one thing at a time.

jeremydeanlakey2• 2 years ago

To make this more concrete:

If your service layer method requires data to be saved and the results to be sorted, you want to call a data layer method that saves it and a library method that sorts it. You do not want any of that saving or sorting functionality in your service method.

Combining different layers and different tasks so that your module is "deep" rather than "shallow" will make your code much higher cognitive load and create a lot of bugs.

jillesvangurp• 2 years ago

There are some nice studies on correlations between metrics (cohesiveness, coupling, complexity, levels of indirection, etc.) and maintainability. Basically anything that scores poorly is inherently hard to understand because it induces a high cognitive load.

The reason what you outline is bad is because they each impact these metrics. Bypassing layers creates a more tight coupling: you are basically putting code in the wrong place. This also makes the code less coherent. The two go hand in hand. And then you end up doing complex things like reaching deep into layers (which violates Demeter's law).

Anyway, MVC style architectures have always had the problem that they invite people to mix viewer and controller code and logic. And once your business logic mixes with your rendering logic, your code is well on its way of becoming yet another UI project that fell into the trap of tight coupling, low cohesiveness, and high complexity.

James_K• 2 years ago

I hate these silly little code examples where they show some if condition being changed to another format and act as if that's real advice that helps you program.

jakobov• 2 years ago

Yes 100%!

Read "Code is For Humans" for more on the subject https://www.amazon.com/dp/B0CN6PQ42B

halfcat• 2 years ago

I suspect part of the challenge is we’re dealing with a graph (of execution paths) but all we have to work with is a tree (file system).

Every person will prefer a different grouping the execution paths that lowers their cognitive load. But for any way you group execution paths, you exclude a different grouping that would have been beneficial to someone working at a different level of abstraction.

So you like your function that fits in one computer screen, but that increases the cognitive load on someone else who’s working on a different problem that has cross-cutting concerns across many modules. If you have separate frontend/backend teams you’ll like Rails, but a team of full stack people will prefer Django (just because they group the same things differently).

I guess this is just Conway’s law again?

DarkNova62• 2 years ago

Layered architecture: Abstraction is supposed to hide complexity, here it just adds indirection

Agree with everything except this. As someone who deals with workflows and complex business domains, separating your technical concerns from your core domain is not only necessary. They are a key means to survival.

Once you have 3 different input-channels and 5 external systems you need to call, you absolutely need to keep your distance not to pollute your core representation of the actual problem you need to solve.

ImPleadThe5th• 2 years ago

As with all things, it's useful used properly.

The codebase at my job has far too many abstractions/layers for things that do not provide any benefit for being abstract. It was simply done because it was the "coderly" thing to do.

I do agree that at the least it makes sense to separate out repository logic.

Spiwux• 2 years ago

I don't understand the architecture section. The title is "layered architecture," but then it talks about Ports/Adapters, which would be hexagonal architecture?

atoav• 2 years ago

Programmers and tech people should understand why cognitive load needs to be reduced.

All of us would scream if we saw how some bureaucrat at a government office makes you fill out some form digitally only to print it out and then type off the printout, only to print it out and give it to their collegue, who.. you get the point.

This is a problem that could be solved perfectly by a good IT process — a process which instead of multiplying work instead reduces it.

Yet programmers and nerds tend to similar wasteful behaviour when it comes to cognitive load. "Why should I explain the code — it speaks for itself" can be similarily foolish. You already spent all that time to think about and understand your code, so why let that all go to waste and throw out all clues that would help even other hardcore nerds to orient themselves? Good code is clear code, good projects are like a good spaceship: the hero who never has been in this ship knows which button to press, because you — the engineer — made sure the obvious button does the obvious thing. More often than not that hero is your future self.

People reading our code, readmes and using our interfaces got all kind of things on their minds, the best we can do is not waste their mental capacity without a good reason.

jschrf2• 2 years ago

Very cool article. Semantics are important and key. Article nails it.

Reduce, reduce, and then reduce farther.

I'll add my 2c: Ditch the cargo cults. Biggest problem in software dev. I say this 30 years in.

Hard lesson for any young engineers: You don't need X, Y, or Z. It's already been invented. Stop re-inventing. Do so obsessively. You don't GraphQL. You don't need NoSQL. Downvote away.

Pick a language, pick a database, get sleep.

Never trust the mass thought. Cargo culting is world destroying.

csomar• 2 years ago

Stop re-inventing.
You don't GraphQL.

Isn't that... ironic? You can Postgres -> GraphQL pretty much without code (pg_graphql). And then link your interfaces with the GraphQL endpoints with little code. Why re-invent with REST APIs?

mrkeen6• 2 years ago

Stop re-inventing. You don't need NoSQL.

I need somewhere for my objects to live. Objects are not relations.

Scattering their data across five tables, to fit the relational model, so I can later JOIN them together again, has to be the biggest example of cargo culting in the whole field.

randomcatuser• 2 years ago

super interesting "short/long" slider on the right -- what made you come up with this UI concept?

wruza• 2 years ago

That’s why I strangely love some closed enterprise solutions. They are anti-fun, non-extensible behemots that you can learn in around five years and then it’s basically all free. If you can stand everything else, ofc.

The open source world could learn from that, by holding up on spiral rotation of ideas (easily observable to turn 360 in under a decade) and not promoting techniques that are not fundamental to a specific development environment. E.g. functional or macro/dsl ideas in a language that is not naturally functional or macro/that-dsl by stdlib or other coding standards. Or complex paradigms instead of few pages of clear code.

Most of it comes from the ability to change things and create idioms, but this ability alone doesn’t make one a good change/idiom designer. As a result, changes are chaotic and driven by impression rather than actual usefulness (clearly indicated by spiraling). Since globally there’s no change prohibition, but “mainstream” still is a phenomenon, the possibility of temperate design is greatly depressed.

nbyron• 2 years ago

The spirit of this piece is excellent, and introduces some useful terms from psychology to help codify - and more importantly, explain - how to make tasks less unnecessarily demanding.

However, as someone who spends their days teaching and writing about cognitive psychology, worth clarifying that this isn’t quite correct:

Intrinsic - caused by the inherent difficulty of a task. It can't be reduced, it's at the very heart of software development.

Intrinsic load is a function of the element interactivity that results within a task (the degree to which different elements, or items, that you need to think about interact and rely upon one another), and prior knowledge.

You can’t really reduce element interactivity if you want to keep the task itself intact. However if it’s possible to break a task down into sub tasks then you can often reduce this somewhat, at the expense of efficiency.

However, you can absolutely affect the prior knowledge factor that influences intrinsic load. The author speaks of the finding from Cowan (2001) that working memory can process 4+—1 items simultaneously, but what most people neglect here is that what constitutes an “item” is wholly depending upon the schemas that a given person has embedded in their long-term memory. Example: someone with no scientific knowledge may look at O2 + C6H12O6 -> CO2 + H2O as potentially up to 18 items of information to handle (then individual characters), whereas someone with some experience of biology may instead handle this entire expression as a single unit - using their knowledge in long-term memory to “chunk” this string as a single unit - ‘the unbalanced symbol equation for respiration’.

energy1232• 2 years ago

Another good article, not directly related to work tasks, but related to unnecessary complexity: https://news.ycombinator.com/item?id=30802349

ilrwbwrkhv• 2 years ago

Another interesting thing is when there is inherent complexity in the system, things remain simple.

For example in game programming, nobody is doing function currying.

And yet in React and frontend land because it is a button on screen which toggles a boolean field in the db, there are graphs, render cycles, "use client", "use server", "dynamic islands", "dependency arrays" etc. This is the coding equivalent of bullshit jobs.

afarviral2• 2 years ago

What's the alternative in front-end? I had assumed those things were needed to essentially reverse engineer the web to be more reactive and stateful? Genuinely want it to be simpler.

AIorNot• 2 years ago

The FUNDAMENTAL aspect and nature of ALL Software Engineering is: "Controlling Complexity" I dare say its the most important part of the "Engineering" in software engineering. 'Cognitive Load' is another way of saying this..

1. programming => wiring shit together and something happens

2. software engineering => using experience, skills and user and fellow engineer empathy to iterate toward a sustainable mass of code that makes something happen in a predictable way

It is exceedingly difficult to do this right and even when you do it right, what was right at one time becomes tomorrow's 'Chesterton's Fence' (https://thoughtbot.com/blog/chestertons-fence) , but I have worked on projects and code where this was achieved at least somewhat sustainably (usually under the vision of a single, great developer). Unfortunately the economics of modern development means we let the tools and environments handle our complexity and just scrap and rewrite code to meet deadlines..

I mean look at the state of web development these days https://www.youtube.com/watch?v=aWfYxg-Ypm4

userbinator3• 2 years ago

When one of these articles come up, I always wonder if the authors have ever looked at APL-family languages and the people who use them, or those who have a similar ultra-compact style even with more mainstream languages; here are the most memorable examples that come to mind:

https://news.ycombinator.com/item?id=8558822

https://news.ycombinator.com/item?id=28491562

What's the "cognitive load" of these? Would you rather stare at a few lines of code for an hour and be enlightened, or spend the same amount of time wading through a dozen or more files and still struggle to understand how the whole thing works?

sharkjacobs• 2 years ago

If you keep the cognitive load low, people can contribute to your codebase within the first few hours of joining your company.

I guess there’s a lot of wiggle room for what is really being asserted here, but this seems like an absurd impossible claim.

zero_one• 2 years ago

Fighting games have a term for this: "mental stack".

https://glossary.infil.net/?t=Mental%20Stack

joshdavham• 2 years ago

Further reading: "The Magical Number Seven, Plus or Minus Two" https://en.wikipedia.org/wiki/The_Magical_Number_Seven,_Plus...

odyssey7• 2 years ago

One day, the world will rediscover functional programming. The absence of state mutation is a beautiful thing.

iandanforth• 2 years ago

I was nodding along happily until I watched the composition is better than inheritance linked video and it suggested the abomination of passing a "base" class instance to the save method of a more specific class instance to give the specific class access to functionality on the "base" class. There may be a solid argument for composition over inheritance but this bastardization of functional and OO programming ain't it.

singingfish3• 2 years ago

Aligning the computer's and the humans' thinking processes. Cognitive load is exceptionally important - one of the few uncontravenable facts in human psychology is that healthy human short term memory has a capacity of 5 items plus or minus 2. So reliably 5. And thus the maximum number of thinking balls you should be juggling at one time.

Which then leads to thinking about designs that lead to the management of cognitive load - thus the nature of the balls changes due to things like chunking and context. Which are theoretical constructs that came out of that memory research.

So yes, this is pretty much principal zero - cognitive load and understanding the theory underneath it are the most important thing - and are closely related to the two hard problems in computer science (cache invalidation, naming things and off by one errors).

Thank you for attending my TED talk

lwhi• 2 years ago

I support Tailwind for precisely this reason.

resters• 2 years ago

You can always tell an intellectually limited programmer when their code requires thinking too hard.

m3kw9• 2 years ago

Every little advantage matters. Code spacing rules for example, your eyes go to the position where it is expected without a new search. Use simple APIs, don’t use new shiny things, don’t go beyond the most simple abstraction(personal thing)

LAC-Tech4• 2 years ago

Enjoyed this post. A lot of it resonated with me, here's some of my thoughts:

Too many small methods, classes or modules

Realized I was guilty of this this year: on a whim I deleted a couple of "helper" structs in a side project, and the end result was the code was much shorter and my "longest" method was about... 12 lines. I think, like a lot of people, I did this as an overreaction to those 20 times indented, multiple page long functions we've all come across and despised.

No port/adapter terms to learn

This came under the criticism of "layered architecture", and I don't think this is fair. The whole point of the ports/adaptors (or hexagon) architecture was that you had one big business logic thing in the middle that communicated with the outside world via little adapters. It's the exact opposite of horizontal layering.

People say "We write code in DDD", which is a bit strange, because DDD is about problem space, not about solution space.

1. I really should re-read the book now I'm a bit more seasoned. 2. I have noticed this is a really common pattern. Something that's more of a process, or design pattern, or even mathematical construct gets turned into code and now people can't look past the code (see also: CRDTs, reactive programming, single page applications...).

Involve junior developers in architecture reviews. They will help you to identify the mentally demanding areas.

Years later I remembered how impress that a boss of mine leveraged my disgust at a legacy codebase, and my failure to understand it as a junior (partly my fault, partly the code bases fault..), by chanelling my desire to refactor into something that had direct operational benefits, and not the shot gun scatter refactoring I kept eagerly doing.

Tainnor6• 2 years ago

I'm sorry but this article is really bad.

I agree that cognitive load matters. What this article completely fails to understand is that you can learn things, and when you've learned and internalised certain things, they stop occupying your mental space.

"Reducing mental load" should be about avoiding non-local reasoning, inconsistencies in style/patterns/architecture, and yes, maybe even about not using some niche technology for a minor use case. But it shouldn't be about not using advanced language features or avoiding architecture and just stuffing everything in one place.

gnarbarian• 2 years ago

you're right. but it's so hard to enforce.

ChuckMcM• 2 years ago

I agree with the author's point. It was the founding principle of "object oriented" programming in that once the object was a black box, you could just rely on it working and let go of the implementation details. But it is also important in day to day work. I remember when I realized that I could only keep six distinct "disasters" in my head at the same time. Trying to add another one would pop one out of my head. So much of life can be simplified if you systematize things so that the thing to remember is small, like all of the stuff you take on business trips (shave kit, travel charger, noise cancelling headphones, whatever) if you put all of it in a box in your closet labelled "travel kit" then you only have to remember three things, outfits for 'n' days, your laptop, and your travel kit. Got those three and you are good to go.

pcblues3• 2 years ago

I'm a fan of using the least number of language features to get the job done. If a language is simple and can be stepped through easily, one benefits from the removal of the added cognitive load of knowing a large number of language features. This provides extra brainspace to understand the problem space and the system one is working on. Most importantly, it makes it easier to have the whole shebang in your mind while you add code (correctly.)

And it adds to maintainability (so long as done in a balanced way!)

I had a boss who saw me looking out a window say, "You look like you are concentrating. I'll come back later."

I document EVERYTHING I think straight away into their appropriate documents so I can forget about it while I'm loading as much of a system's design into my head as I can. It allows me to write good code during that small window of available zen. After years of doing that, I made a document about documentation. Hope it's of use. https://pcblues.com/assets/approaching_software_projects.pdf

pcblues3• 2 years ago

Also, it's important that you make your own templates for each of the document types, because thinking about them is part of the design process. It reduces the cognitive load of understanding yet another set of design document templates, and they are malleable in your own hands :)

at_a_remove2• 2 years ago

I agree and will add in a few bits: although I will obey the language's idiom, in general, I like to keep the number of "things it does" per line of code to the minimum. Kind of an anti-code golf.

I also document (or comment code) when I am waiting for the flow to kick in. For me, the documentation starts at the appendices. One for input files or api source tricks or describing the input tables in a database. Another for the relevant outputs. Maybe a "justify overall design decisions" section. Just stuff someone would wish if they had to handle it in five years.

pcblues3• 2 years ago

I wonder why people boast they can do ten things in one line. Less lines of code doesn't mean less bugs. The debugger just stops at each symbol instead of each line which I think adds to the cognitive load.

Documenting while waiting for the flow is like stretching before exercise. It gets you to that place :)

I got my experience/slaps by fixing my own code in the same codebase for more than ten years. I have empathy for the future maintainers :)

userbinator3• 2 years ago

I'm a fan of using the least number of language features to get the job done.

Some people seem to love doing the opposite, which IMHO is the biggest problem with the software industry --- there's a huge number of developers who think that the more complex (or in their words, "structured") software is, and the more latest language features it has, is somehow better than the simple "deprecated" stuff that's been working for decades.

I've come to the conclusion that a lot of new language features are there only for the benefit of trendchasers and worshippers of planned obsolescence, and not the users nor the developers on their side.

namaria7• 2 years ago

Funny thing is, humans have a huge bias towards traditions that seems to have reversed in the last century or so.

My take is that consumerism did a number on our psyche.

whilenot-dev3• 2 years ago

I've come to the conclusion that a lot of new language features are there only for the benefit of trendchasers and worshippers of planned obsolescence, and not the users nor the developers on their side.

What are your thoughts on aync/await then (available in Python/JavaScript etc.)?

chuckadams• 2 years ago

I think the biggest problem with the software industry is all the people who insist that everything that everyone else does is the biggest problem with the software industry.

I guess that set includes me now ¯\_(ツ)_/¯

Tainnor6• 2 years ago

If a language is simple and can be stepped through easily, one benefits from the removal of the added cognitive load of knowing a large number of language features.

Things that you know and have internalised don't occupy your brainspace. That's why you can read this paragraph without having to think about every word individually.

qw• 2 years ago

Things that you know and have internalised don't occupy your brainspace

Some "10x" developers are extremely productive because they know the software stack inside and out.

There are also "10x" teams where they share an institutional knowledge of the software stack and are constantly improving and finding more efficient ways of solving a problem. When someone finds a better library, more efficient CI/CD or establish new code practices it is easy to apply it when they have a single stack to focus on.

It's hard to replicate this in teams where they are responsible for 10 micro services, each written in their own language and using different software stacks that are more "optimal" for some use case.

pkkkzip• 2 years ago

I remember I had this argument with a CTO before about cognitive load. I was concerned of the sheer amount of code behind React/Redux for what could've been just a simple plain server rendered with jQuery sprinkled.

Her answer was "if Facebook (before meta) is doing it then so should we."

I said we aren't facebook. But all the engineers sided with her.

Said startup failed after burning $XX million dollars for a product nobody bought.

guywhocodes2• 2 years ago

A tale as old as the SPA

RandomWorker• 2 years ago

This is the best article I've read on programming in a while. When I code all I do is work on one object or one function at a time. Working usually on the end result. The key here is to develop a quick and easy solution without too many issues. This is also the difference between new and experienced developers. Experienced developers have less fluid intelligence so build reliable simple programs.

galaxyLogic2• 2 years ago

I think it is somewhat misguided notion that code could have a property whose value is its "cognitive load". Instead we should start from the premise that:

1. Somebody writes a program

2. Somebody else (perhaps the same programmer a few years later) tries to read and understand that program

So the "cognitive load" is a property of the communication between the person who writes the program and others who read and (try to) understand the program.

Cognitive Load is an attribute of communication, not of the artifact that is the medium of the communication (i.r. the code written).

Are we writing in a "language" that readers will understand? And are we reading in a way that our assumptions about what the writer is trying communicate to us are correct?

A program is instructions to the computer. But when written in a highj-level language it is also meant to be read by other prrogrammers, not just by the CPU. It is human-to-human communication. How easy is it for somebody to understand what somebody else is trying to tell the computer to do? That's the "Cognitive Load".

ajuc4• 2 years ago

Code is 95% of the communication.

And how overcomplicated the code is has a huge (overwhelming everything else) influence on how hard it is to communicate what it does.

So in practice it's fair to call it the property of the code, even if bad documentation or mentoring can make things unnecessarily worse.

Solar system can be modeled as geocentric with enough epicycles, or as heliocentric system with eliptical orbits.

One of these is inherently easier to communicate.

galaxyLogic2• 2 years ago

Right, I was just trying to bring up the point that however the code is written, what really matters is, how easily humans can understand it.

Now maybe there is, or can be an algorithm that takes a piece of code and spits out a number saying how easy it is for a typical programmer to understand it correctly. That would be the measure of "cognitive load".

If we just speak of cognitive load without really specifying how to measure it, we are not where we would like to be.

How do we define, and measure "cognitive load"? It is an easy word to use, but how to measure it?

majgr• 2 years ago

My whole experience of working 18 years as a software developer can be summed up with two words: ‚it depends’. Every nice architecture set up front breaks at some point. There is no silver bullet.

swiftcoder• 2 years ago

By no means I am trying to blame C++. I love the language. It's just that I am tired now.

I feel that in my bones.

tugu775• 2 years ago

We were told that a really smart developer had contributed to it. Lots of cool architectures, fancy libraries and trendy technologies were used. In other words, the author had created a high cognitive load for us.

Maybe that dev was "really smart" but then not very senior. Eventually the dev will hopefully use their smarts to make things so simple+dumb that the cognitive load when maintaining all that code is minimized.

One of the first things I try to drill into our junior devs. If the code looks smart, it needs to be fixed until it's really simple and straight forward. "That's impossible" some people might say. And that's why only the really smart folks can achieve it.

sesm• 2 years ago

make things so simple+dumb that the cognitive load when maintaining all that code is minimized.

That's not very smart in BigCo, instead you want the complexity to leak into adjacent systems and make them depend on you.

tugu775• 2 years ago

I know your comment is a little tongue-in-cheek, but that kind of thinking is in fact widespread and a reason why many of us are so miserable.

jonplackett• 2 years ago

Lots of board games exploit this - eg settlers of catan has 5 resources and it’s really hard to think about all 5 at once. You always forget one! (Well I do anyway)

tugu775• 2 years ago

Re: complex conditionals

I contributed some code to a FOSS project recently which is written in C. In my 10 lines of contributions, 3 were a complex conditional. I'd have loved to do what the article suggests, with some intermediate booleans. But that C version would have required me to define those variables at the beginning of the function, a hundred lines earlier instead of just right there. No way that's going to fly, so now they will need to live with a complex conditional. It's one of those "modern language" features which C fanatics generally frown upon but which makes code much easier to read.

mrkeen6• 2 years ago

Can you not move to c99?

pegas1• 2 years ago

Yes, I remember those times, trying to do structured programming in the unstructured environment. So, we both know that even very complex conditionals can be made readable by CRLFs, TABs, and inline comments. It is not about the language, it is about the person.

fullstackchris• 2 years ago

Fantastic post already by the first example. Meanwhile I can think of big brain developers who have laughed at me "because you assigned to a variable what you use once"... good luck with your career

This post is like an examplified grugbrain.dev

riedel• 2 years ago

Just a quick note on cognitive load theory: what makes cognitive load difficult is 'germane cognitive load' that comes from learning, that is neither intrisinsic nor extraneous. Getting it right is difficult: often too light interfaces can also be too light on actual understanding. What makes it worse it is nearly impossible to measure how much is extraneous and what is germane.

kazinator2• 2 years ago

Prefer composition over inheritance.

Why? Because if SuperuserController is built on AdminController via composition rather than inheritance, it is magically protected from breakage due to changes in AdminController?

Not buying it.

dominicrose• 2 years ago

Great article. Even smart people can get tired at some point. In fact reducing cognitive load IS the smart thing to do. It's good to bring awareness to this. I like simple rules that help reduce cognitive load, and can be shared in pull requests. Simple things like early returns.

Rules like "limit the number of lines to 300" are meant to be broken. Some 2k-line code files are easy to understand, some are not. It depends. It always depends.

neillyons• 2 years ago

Cognitive load example in Go. It is common to give variables single letter names. Now you have to build up a mapping in your head that for example `a` means `Auction`. You could skip this mapping if you just named the variable `auction`.

haffi112• 2 years ago

This post reminded me of Nevernesting: https://www.youtube.com/watch?v=CFRhGnuXG-4

euph0ria5• 2 years ago

Really liked this! Thanks!

leke• 2 years ago

Yep, someone read John K. Ousterhout's book.

DanielBMarkham• 2 years ago

Related: From ~5 years ago.

https://danielbmarkham.com/for-the-love-of-all-thats-holy-us...

Understanding CCL is both critically important and will sink you into deep professional despair once you realize that the coding community has deep-set standards and social mores that prevent serious adoption.

lo_zamoyski• 2 years ago

The cognitive load associated with abstractions that the author seems to mention isn’t caused by abstractions, but by leakiness or inadequacy of the abstraction family.

In an ideal setting, when solving a problem, we first produce a language for the domain of discourse with a closure propery, i.e., operations of the language defined over terms of the language produce terms in the same language. Abstraction is effectively the process of implementing terms in the language of this domain of discourse using some existing implementation language. When our language does not align with the language of discourse for a problem, this adds cognitive load, because instead of remaining focused on the terms of the language of discourse, we are now in the business of tracking book keeping information in our heads. That book keeping is supposed to be handled by the abstraction in a consistent manner to simulate the language of discourse.

So you end up with a hodgepodge of mixed metaphors and concepts and bits and pieces of languages that are out of context.

Of course, in practice, the language of discourse is often an evolving or developing thing, and laziness and time constraints cause people to do what is momentarily expedient versus correct. Furthermore, machine limitations mean that what might be natural to express in a language of discourse may not be terribly efficient to simulate on a physical machine (without some kind of optimization, at least). So you get half measures or grammatically strange expressions that require knowledge of the implementation constraints to understand.

z3t42• 2 years ago

Coding is very personal and fashion driven. Everyone's brain work different. It's all random events that forms our thinking. A software project is too big when you can no longer see the full picture - then you should break it down to independent parts. State is your enemy.

moffkalast• 2 years ago

Or alternatively, download more brain.

Yeah, this is big brain time.

ibash• 2 years ago

State is not the enemy.

Encapsulated and managed state is just fine.

mrkeen6• 2 years ago

Yeah but they're a statistical anomaly in the field.

For every example of encapsulated state, there's probably 9 more examples of global state which is called encapsulated.

And what is managed state? I can think of two examples that can effectively manage it - software transactional memory, and a good rdbms with the isolation level turned way up.

z3t42• 2 years ago

It's not that easy, say for example if a over excited user clicks the purchase button 20 times, ending up in 20 simultaneous orders. What is the best way to handle it? Should the user get 20 orders shipped to him, or only one? And should the user get a message that says "order already processed" or "order processed successfully"? You can have a system that works correctly 99% of the time. The devil is in the 1% of time when things go wrong.

mark_l_watson2• 2 years ago

I have been programming since 1963 and I was a Master Software Engineer at Capital One before I retired. I have my own ways of managing cognitive load. I usually use Lisp languages, Python, and Haskell and I tend to write my own short libraries and then treat these libraries as black boxes unless I want to extend them. I obviously use a zillion libraries that other people write also, but there is a comfort and ease using my own code.

matesz• 2 years ago

Have you tried Clojure?

mark_l_watson2• 2 years ago

A few years paid to write Clojure.

WillAdams• 2 years ago

A more formal look at this is Ousterhout's _A Philosophy of Software Design_

which has been specifically discussed extensively here:

https://news.ycombinator.com/item?id=27686818

https://news.ycombinator.com/item?id=37975558

https://news.ycombinator.com/item?id=31248641

including more peripherally:

https://news.ycombinator.com/item?id=34733120

ipython• 2 years ago

I’m not sure I’d use the Unix io interface as a shining example of reducing cognitive load. Sure, it’s a simple interface on the surface but…

Let’s just take write() as an example. Just calling write() does not guarantee that the full contents were written to the file. You could have the case where write() wrote nothing, or some data, but was interrupted because of a signal before it completed. Or you could have a short write because of a quota or disk limit.

And I’m sure I’ll be nerd sniped shortly with even more obscure examples of the sharp edges awaiting you in such a “simple” interface. (For a more snarky version of my comment, see the last essay “the rise of worse is better” of the Unix haters handbook: https://web.mit.edu/~simsong/www/ugh.pdf)

Point is, this interface just shifts cognitive load on to the application developer - it’s got to go somewhere after all.

C-programmer• 2 years ago

`write` can format your disk if a trickster sets LD_PRELOAD to a malicious shared object.

nateglims• 2 years ago

So much is crammed into ioctl or fcntl. Especially if you are trying to treat UART, SPI, I2C, etc the same by supplying the I/O interface.

wnmurphy• 2 years ago

Introduce intermediate variables with meaningful names

Abstracting chunks of compound conditionals into easy-to-read variables is one of my favorite techniques. Underrated.

isValid = val > someConstant
isAllowed = condition2 || condition3
isSecure = condition4 && !condition5
if isValid && isAllowed && isSecure { //...

goalieca• 2 years ago

I treat it a lot like english. Run-on sentences, too much technical jargon, and too many fragmented short sentences all make it harder to read. There's analogies to writing code.

RaftPeople3• 2 years ago

Abstracting chunks of compound conditionals into easy-to-read variables is one of my favorite techniques. Underrated.

Same. Or alternatively I will just put the English version in comments above each portion of the conditional, makes it easy to read and understand.

AtlasBarfed• 2 years ago

So you like procedural code.

I mean, at least western people seem to think in recipes, todo lists, or numbered instructions. Which is what procedural code is.

Dogma will chop up those blocks into sometimes a dozen functions, and that's in stuff like Java, functional is even worse for "function misdirection / short term memory overload".

I don't really mind the hundred line method if that thing is doing the real meat of the work. I find stepping through code to be helpful, and those types of methods/functions/code are easy to track. Lots of functions? You have to set breakpoints or step into the functions, and who knows if you are stepping into a library function or a code-relevant function.

Of course a thousand line method may be a bit much too, but the dogma for a long time was "more than ten lines? subdivide into more functions" which was always weird to me.

0xbadcafebee• 2 years ago

I hate to be the bearer of bad news, but this entire concept within the space of computer science is cargo cult repetition.

Cognitive load as the general HN viewer knows it doesn't exist. (Or at least, if the concept solely consists of "thinking hard! thinking many things more hard!", it's not worthy of a phrase)

Cognitive load, and cognitive load theory, do exist as concepts, outside of computer science. Yet none of it is reflected in HN posts. Somebody just heard the phrase once, thought it sounded cool, didn't learn about, and started blogging, making up what they thought it meant. Without the actual body of knowledge and research, its use in computer science is just buzzword fuckery, its understanding by the casual HN reader clear as mud. Without nuance, research and evidence, it's nonsense masquerading as wisdom.

If all you know is parroted anecdotes and personal experience, you're not doing science, you're doing arts & crafts.

sourcecodeplz• 2 years ago

Wow what a great read, thank you so much for this! I think every dev should read this at least once

nogridbag3• 2 years ago

I'm probably late to the party, but I was hoping to see a larger discussion on "Too many small methods, classes or modules" aka Deep Module vs Shallow Modules. I think we can probably debate just that last sentence alone for a while. I would imagine "module" here simply means a group of classes that are collectively related. Having "too many modules" is likely just the implicit complexity of the problem you're trying to solve. You either have all those modules or you have no product. If all products were trivial to code, no one would be employing you to create the product.

So the main thing we typically come across is "too many classes" and that's the example the author gave in the article. Nearly all the developers at my company go with the "throw everything into one class" approach regardless whether they're junior, senior, etc. I tend to go the extreme opposite route and usually create small classes for things that seem critical to test in isolation. While I'm coding that small class and writing unit tests, it feels perfect. When I revisit the code, it is a bit overwhelming to understand the relationships between the classes. So I understand the article's criticisms of too many small classes.

However, I have my doubts that moving this class into the main class as a simple method would reduce cognitive load. For one, due to the nature of our tools, e.g. JUnit, I would be forced to make that method public in order to test it (and now it's part of the large class's API contract). So I can either make it public, remove my unit tests, or attempt to make my unit tests part of the greater component's test which really overcomplicates the parent's unit tests. Ignoring the testing issue, is the cognitive load complexity just a file structure issue? Instead of turning those small classes into methods in a large class, I could just use nested classes in a single file. Or, there can be some package naming convention so readers know "these helper classes are only used by this parent class". I would be interested to hear others thoughts, but due to the nature of HN's algorithm, it's likely too late too see many replies :)

fmbb2• 2 years ago

Ignoring the testing issue

I mean it sounds to me like testing is your only problem so it’s kind of hard to ignore.

Personally I prefer fewer larger modules over more smaller modules. Deeply nested code is harder for me to reason about, I need to push stuff on my stack more often as I go down a debugging rabbit hole.

You can never reason locally about a bug. All code looks good locally. Bugs always manifest in the totality of your code and that is where you have to look at it. Your unit tests for the release running on production are all green, someone reviews all those lines that are in there. Locally it all made sense, local reasoning is how you ended up with that bug in production.

If you write a small little class with one method to help implement some bigger interaction, if your change does not touch the unit tests of the ”wrapper” class actually implementing the bigger interaction, what the users use, you are likely writing meaningless code or your test coverage for the actual use cases is not good enough.

nogridbag3• 2 years ago

if your change does not touch the unit tests of the ”wrapper” class

I don't think this is a good example. In fact, this is more supportive of having the small little class. The "wrapper" class only needs to have 1-2 unit tests to test the scenarios in which the small little class is invoked without needing to be concerned with the complexity of everything that small little class is actually doing. I've never written a small helper class without writing corresponding tests in the wrapper so I've never had that problem - it's usually the first thing I write after adding the helper class. For that specific problem there's automated and manual processes anyway. Code coverage tools can easily tell you if you missed writing tests for the invocation and reviewers should spot that in PR reviews.

throw4847285• 2 years ago

I think this is compelling programming advice, but "cognitive load" isn't adding anything. The problem with popularizing a term like cognitive load is that it just becomes a new more scientific term for an existing concept in folk psychology. It can then be applied, detached from any experimental psych, to anybody's personal bugbear.

"This programming paradigm is bad because cognitive load" becomes identical to "this programming paradigm is bad because it isn't simple" and then simple is such a fuzzy concept that you can define whatever you like as simple and whatever you don't as having high cognitive load.

frou_dh• 2 years ago

then simple is such a fuzzy concept that you can define whatever you like as simple and whatever you don't as having high cognitive load.

Good observation. That is absolutely rampant in online programmer discussions/flame-wars. Which is why Rich Hickey's classic presentation Simple Made Easy, although not the last word on the topic, at least tried to bring some objectivity to what simple is.

rTX5CMRXIfFG2• 2 years ago

Which is why engineers who intend to use the term in their discussions shouldn’t dumb it down or loosely define it in their own words, and cite the definition from authoritative sources, say reference texts.

And whenever it is being used as an argument to reject or approve code, just saying “because cognitive load” should not be accepted as enough. Instead, there should be an accompanying explanation for what exactly in the code raises the cognitive load and what mechanisms come into play that creates the cognitive load according to cognitive science. (Note: I’m using “science” here as opposed to just “psychology”, because the ana/physio of human memory is not exclusive to the domain of psychology.)

phreack• 2 years ago

Another prong in the cognitive load fork that's trying to stab you when working, is the UX of your tools.

That is absolutely personal, but it pays off massively in the long term to build out a development environment that you're comfortable with. If it's an IDE, you can try to recognize pain points like nested tools you use often and bring them to the front via new buttons or learning hotkeys.

UI is also important, in "modern" IDEs there's an awful trend of not labeling icons, so I strictly use one that does so I don't have to juggle "which doodle is the Git button again" on top of my actual work cognitive load.

nox101• 2 years ago

This reminds me of Joel Splosky's "Making Wrong Code Look Wrong"

https://www.joelonsoftware.com/2005/05/11/making-wrong-code-...

By writing code in a certain way, at a glance you could tell if it's correct or wrong. Most people suggesting making types handle this but that's a level of abstraction. If I have

    v = a + b

If I don't know what a and b are but have to go check their types then I don't know if that code is correct. You could argue if you have good types then of course it's correct but that still misses the point that I don't know what a and b are.

Names help

   html = fieldName + fieldValue

But that's not enough. are fieldName and fieldValue safe? No way to tell here. You could make a SafeString class and that would be good but you're still adding the load that you have to look up the definitions of these variables to know what's going on. The info you need is not here at this line.

Then again, I've never been able to get myself to follow the advice of that article.

dherikb• 2 years ago

Mantras like "methods should be shorter than 15 lines of code" or "classes should be small" turned out to be somewhat wrong.

I really have some concerns about this kind of opinion.

I know that we can't follow this rule (or smell) every time, but I already see this affirmation being used by very poor or inexperienced programmers to justify understandable gigantic and hard to test pieces of code.

This is the type of advice that just experienced programmers can understand what this means and know when is applied.

Most part of the time, it's easier to fix a cod

brundolf• 2 years ago

Very similar premise to Rich Hickey's "Simple Made Easy" (frequently linked on HN but felt especially relevant)

https://www.infoq.com/presentations/Simple-Made-Easy/

DrNosferatu• 2 years ago

Cognitive load allows gatekeeper devs to keep* their job. Very difficult to ever see this to change.

jbs789• 2 years ago

There was an article recently about the importance of designing the function signature, and I connect that to creating the appropriate level of abstraction, which also connects to this. Guess it’s all about creating the right interfaces, but I’m not really a programmer…

laxk• 2 years ago

TL;DR:

- use principles as guidelines not gospel

- optimize for readability/maintainability

- and for the love of all that's holy, don't build stuff you don't need yet.

BTW, any other old-timers remember when we just wrote code without worrying if it was SOLID enough? Those were the days...

MiscCompFacts• 2 years ago

I really enjoyed this post quite abit, and it’s a topic that I and many developers have discussed concerning good abstractions. This isn’t directly related to the article it’s self, but to the website minds.md. I was surprised to see it seems like a blogging platform for various authors but I didn’t see any information about where to upload or who runs this service. It mentions GitHub but doesn’t seem to link to it on the home page. Just curious to know more about this site and if it’s for anyone or a specific group of people?

adr1an• 2 years ago

I believe it's specific to a group of people, since the site has 3 posts. Yet, this post is a living document awaiting contributions (or so it claims), https://github.com/zakirullin/cognitive-load

zakirullin• 2 years ago

Thank you :)

It's open to everyone, I'll post more information on the site.

Though I really want some strong moderation. Too much generalized/LLM content on the web nowadays...

blahbleuuuudsu• 2 years ago

If a stack trace has too many levels. That is enough proof for me the people building this don't know what they are doing.

kkarpkkarp• 2 years ago

in 1955 George Miller discovered[1] human can only contain 7 bits of information at the time.

Ie. if I write 1452687 and ask you to read it only once and then close eyes and repeat it, you will be able to do this.

If I write 12573945 and ask you to do the same, you will most likely not be able to do it.

Same happens with bigger "bits" of information: you can remember 7 ideas/statements from the textbook you read, so do not trap yourself in "ah that is easy, I will continue reading without taking notes". After every 7 "things" write them down, note the page number where they are and then continue reading. Otherwise it is a waste of time.

[1] https://en.wikipedia.org/wiki/The_Magical_Number_Seven%2C_Pl...

Cognitive load is what matters

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