Go Naming Conventions: A Practical Guide | Hacker News Reader

Go Naming Conventions: A Practical Guide

alexedwards.net

115 pointsyurivish71 comments

> we use the identifier p to represent a value in the people slice — the range block is so small and tight that using a single letter name is clear enough.

No, it's not. When you see `p.Age`, you have to go back and find the body of the loop, see what it operates on and decipher what p stands for. When you see `person.Age`, you understand it. I've never understood what is gained by using `p` instead of spelling it out as `person`.

Long lines make reading rhythm uncomfortable (long jumps, prolonged eye movements) and long words make the text too dense and slow down the reading. It’s bad typography.

I have heard an idea that a good variable should be understood by just reading its name, out of context. That would make “ProductIndex” superior to “i”, which doesn't add any clarity.

I would argue that ambiguity and uncertainty slow down reading, and more importantly comprehension, far more than a few additional characters.

It depends on whom you are optimizing for. Someone who knows the language, but not this system/codebase, or someone who works in this area often?

A good variable name is the one that is understood by reading it in context, which is why you don't have names like "current_person" or "CurrentIndexOfProductBeingUpdated".

Something like "AnIteratorObjectWithPersonPointer" would be a long word, "person" is absolutely not. If a 6 letter identifier causes you that much trouble with code being too verbose, then it's likely a screen resolution/density/font issue, not a naming issue.

> That would make “ProductIndex” superior to “i”, which doesn't add any clarity.

And then you introduce extra two levels of nested loops and suddenly "i", "j", and "k" don't make any sense on their own, but "ProductIndex", "BatchIndex" and "SeriesIndex" do.

And then you introduce extra two levels of nested loops and suddenly "i", "j", and "k" don't make any sense on their own, but "ProductIndex", "BatchIndex" and "SeriesIndex" do.

ijk for indices in loops are actually clearer than random names in nested loops precisely because it is a *very common convention* and because they occur in a defined order. So you always know that "j" is the second nesting level, for instance. Which relates to the visual layout of the code.

You may not have known of this convention or you are unable to apply "the principle of least astonishment". A set of random names for indices is less useful because it communicates less and takes longer to comprehend.

Just like most humans do not read text one letter at a time, many programmers also do not read code as prose. They scan it rapidly looking at shapes and familiar structures. "ProductIndex", "BatchIndex" and "SeriesIndex" do not lend themselves to scanning, so you force people who need to understand the code to slow down to the speed of someone who reads code like they'd read prose. That is a bit amateurish.

I partly agree, and partly don't. When ijk really is unambiguous and the order is common (say you're implementing a well-known algorithm) I totally agree, the convention aids understanding.

But nesting order often doesn't control critical semantics. Personally, it has much more often implied a heuristic about the lengths or types (map, array, linked list) of the collections (i.e. mild tuning for performance but not critical), and it could be done in any order with different surrounding code. There the letters are meaningless, or possibly worse because you can't expect that similar code elsewhere does things in the same nesting order.

This likely depends heavily on your field though.

I think I know what you mean. Let's assume a nesting structure like this:

Company -> Employee -> Device

That is, a company has a number of employees that have a number of devices, and you may want to traverse all cars. If you are not interested in where in the list/array/slice a given employee is, or a given device is, the index is essentually a throwaway variable. You just need it to address an entity. You're really interested in the Person structure -- not its position in a slice. So you'd assign it to a locally scoped variable (pointer or otherwise).

In Go you'd probably say something like:

for _, company := range companies { for _, employee := range company.Employees { for _, device := range employee.Devices // ..do stuff } }

ignoring the indices completely and going for the thing you want (the entity, not its index).

Of course, there are places where you do care about the indices (since you might want to do arithmetic on them). For instance if you are doing image processing or work on dense tensors. Then using the convention borrowed from math tends to be not only convenient, but perhaps even expected.

> ijk for indices in loops are actually clearer than random names in nested loops precisely because it is a very common convention and because they occur in a defined order. So you always know that "j" is the second nesting level, for instance. Which relates to the visual layout of the code.

In problem domains that emphasize multidimensional arrays, yes.

More often nowadays I would see `i` and think "an element of some sequence whose name starts with i". (I tend to use `k` and `v` to iterate keys and values of dictionaries, but spell `item` in full. I couldn't tell you why.)

I think this may be related to how people read code. You have people who scan shapes, and then you have people who read code almost like prose.

I scan shapes. For me, working with people who read code is painful because their code tends to to have less clear "shapes" (more noise) and reads like more like a verbal description.

For instance, one thing I've noticed is the preference for "else if" rather than switch structures. Because they reason in terms of words. And convoluted logic that almost makes sense when you read it out loud, but not when you glance at it.

This is also where I tend to see unnecessarily verbose code like

func isZero(a int) bool { if a == 0 { return true } else { retur false } }

strictly speaking not wrong, but many times slower to absorb. (I think most developers screech to a halt and their brain goes "is there something funny going on in the logic here that would necessitate this?")

I deliberately chose to learn "scanning shapes" as the main way to orient myself because my first mentor showed me how you could navigate code much faster that way. (I'd see him rapidly skip around in source files and got curious how he would read that fast. Turns out he didn't. He just knew what shape the code he was looking for would be).

I think this is pretty insightful, and I might add this as another reason LLM code looks so revolting. It's basically writing prose in a different language, which make sense - it's a _language_ model, it has no structural comprehension to speak of.

Whereas I write code (and expect good code to be written) such that most information is represented structurally: in types, truth tables, shape of interfaces and control flow, etc.

> I think this may be related to how people read code. You have people who scan shapes, and then you have people who read code almost like prose.

I think this is an astute observation.

I think there is another category of "reading" that happens, is what you're reading for "interaction" or "isolation".

Sure c.method is a scalable shape but if your system deals with Cats, Camels, Cars, and Crabs that same c.method when dealing with an abstract api call divorced from the underlying representation might not be as helpful.

I would think that we would have more and better research on this, but the only paper I could find was this: https://arxiv.org/pdf/2110.00785 its a meta analysis of 57 other papers, a decent primer but nothing ground breaking here.

> I scan shapes. ... verbal description.

I would be curious if you frequently use a debugger? Because I tend to find the latter style much more useful (descriptive) in that context.

dealing with an abstract api call divorced from the underlying representation

I don't understand what you mean. Could you give me an example?

I would be curious if you frequently use a debugger?

I practically never use a debugger.

The shape argument works well in small packages but it starts to fail once you have multiple domain models starting with the same letter

I wasn’t talking about just symbols but entire paragraphs of code as well.

> strictly speaking not wrong, but many times slower to absorb. (I think most developers screech to a halt and their brain goes "is there something funny going on in the logic here that would necessitate this?")

I agree with this, but can't see how this applies to variable naming. Variable names can be too long, sure, but in my opinion, very short non-obvious variable names also make scanning and reading harder since they are not familiar shapes like more complete words. Additionally, when trying to understand more deeply, you have to stop and read code more often if variable's meaning is not clear.

That said, 1-2 char variable names work well in short scopes, like in some lambda, or when using 'i' for an index in a loop (nested loops would depend on situation), but those are an exception.

Like always, this is probably subjective too. And well-organized codebase probably helps to keep functions shorter, but there's often not much I can do about the existing codebase having overgrown functions all over.

> That would make “ProductIndex” superior to “i”, which doesn't add any clarity.

Adds a ton of clarity, especially if you have a nested loop.

and god help you if those loops are pairing People and Products.

though now that I write that out... it would be really nice if you could optionally type iteration vars so they couldn't be used on other collections / as plain integers. I haven't seen any languages that do that though, aside from it being difficult to do by accident in proof-oriented languages.

You usually don't need an index that can't be used elsewhere. If you don't then you can abstract it away entirely and use an iterator or foreach features.

Depends on the language. Doing that is a huge pain in Go (until fairly recently, and it's still quite abnormal or closure-heavy), so the vast majority of code there does manual index-pairing instead of e.g. a zip iterator when going through two paired arrays.

I've felt strongly for a while now that abbreviations should be "lossless" in order to be useful; it should be unambiguous now get back to the unabbreviated form. For whatever reason, people seem to love trying to optimize for character count with abbreviations that actually make things more confusing (like `res` in a context where it might mean either "response" or "result).

I just don't get the obsession with terseness when we have modern tooling. I don't type particularly fast, but autocomplete makes it pretty quick for me to type out even longer names, and any decent formatter will split up long lines automatically in a way that's usually sane (and in my experience, the times when it's annoying are usually due to something like a function with way too many arguments or people not wanting to put a subexpression in a separate variable because I guess they don't know that the compiler will just inline it) rather than the names being a few characters too many.

Meanwhile, pretty much everywhere I've worked has had at least some concerns about code reviews either already being or potentially becoming a burden on the team due to the amount of time and effort it takes to read through someone else's code. I feel like more emphasis on making code readable rather than just functional and quick to write would be a sensible thing to consider, but somehow it never seems to be part of the discussion.

> and any decent formatter will split up long lines

Any decent editor can wrap long lines on demand. But it's even better not to have to do either of those if not necessary.

> I've felt strongly for a while now that abbreviations should be "lossless" in order to be useful

This is how we got lpszClassName. The world moved away from hungarian notation and even away from defining types for variables in some contexts (auto in cpp, := in Go, var in Java). Often it just adds noise and makes it harder to understand the code at a glance, not easier.

I'd argue there's a stark difference between abbreviating words and adding extra ones. `p` as a shorthand for `person` is silly to me, but that doesn't mean that `personObject` would also be silly to me. I fundamentally don't agree with the premise that it's possible to be too verbose means that terseness is its own goal; the goal should be clarity, and I don't think that lossy abbreviations actually help with that except when someone already knows what the code is doing, in which case they don't need to read it in the first place.

I agree with this comment so much.

Tried to use the new slices package or comparables? It's a nightmare to debug, for no reason whatsoever. If they would've used interface names like Slice or Comparable or Stringable or something, it would have been so much easier.

The naming conventions are something that really fucks up my coding workflow, and it can be avoided 100% of the time if they would stop with those stupid variable names. I am not a machine, and there is no reason to make code intentionally unreadable.

I think this is clearly a matter of preference. Shorter variable (or rather, appropriately short variables for the context) for me are easier to recognize and disambiguate. They take up fewer tokens, so to speak. When I see `p.Age` I don't have to go back and look at the beginning of the loop because I just read that line and I remember it.

If your loops are so long you can't fit them on one screenfull you have much more fundamental issues.

You arent wrong, but it is not an absolute.

Furniture maker, house framer, finish carpenter are all under the category of woodworking, but these jobs are not the same. Years of honed skill in tool use makes working in the other categories possible, but quality and productivity will suffer.

Does working in JS, on the front end teach you how to code, it sure does. So does working in an embedded system. But these jobs might be further apart than any of the ones I highlighted in the previous category.

There are plenty of combinations of systems and languages where your rule about a screen just isn't going to apply. There are plenty of problems that make scenarios where "ugly loops" are a reality.

I didn't say it was an absolute. But once a scope grows to the point where you have to navigate to absorb a function or a loop, both readability and complexity tends to worsen. As does your mental processing time. Especially for people who "scan" code rapidly rather than reading it.

The slower "readers" will probably not mind as much.

This is why things like function size is usually part of coding standards at a company or on a project. (Look at Google, Linux etc)

person.Age is easier to understand than p.Age regardless of the loop size.

Another point of view: ideally it would just be "Age". But in languages that don't have the ability to "open" scopes, one might be satisfied p.Age, being "the age". I've also seen $.age and it.age, in languages with constructs that automatically break out "it" anaphora.

This is something that it seems some Go people just don't "believe" in my experience, that for some people that letter in that context is not mentally populated immediately.

It's honestly a shame because it seems like Go is a good language but with such extremely opinionated style that is so unpleasant (not just single letters but other things stuff about tests aren't supposed to ever have helpers or test frameworks) feels aggressively bad enough to basically ruin the language for me.

I think the community is split on such things. I ended up telling the side that gets persnickety about short names and only using if statements in tests to pound sand. I use things that make my life easier. I now care less about some rude rando on r/golang than I did five years ago.

>you have to go back and find the body of the loop

If the loop is long enough that you don't naturally remember how it was introduced, that's the problem. In the given example, the use of `p.Age` is literally on the next line of code after ` for _, p := range people`.

> I've never understood what is gained by using `p` instead of spelling it out as `person`.

Wisdom I received from, IIRC, the Perl documentation decades ago: tightly-scoped names should be shorter and less attention-grabbing than more broadly-scoped ones, because you should really notice when you're using a global, and you don't want to suffer attention fatigue. (I'm sure the exact wording was quite different.)

Also because it's better for information density. As I recall, Larry Wall also had the idea that more commonly used language keywords should be shorter than rare ones. Good code uses the locals much more often than globals, so you shouldn't need to expend the same amount of effort on them. (The limiting case of this is functional programming idioms where you can eliminate the variable name completely, in cases like (Python examples) `lambda x: int(x)` -> `int`, or `(foo(x) for x in xs)` -> `map(foo, xs)`.

> remember how it was introduced

The problem is that many times I have not read the definition to remember. Debugger puts me into a context where I have to figure out what `p` stands for. I go up the call stack and now there's `s` to be deciphered. Worse is the reuse of `p` for person, product, part, etc. in different contexts.

Debugging is not the only problem. Code is read rarely linearly. Many times I browse different uses of a function, or see how a data structure is modified in different contexts. Looking up single letter variables is just a waste of time.

> Debugger puts me into a context where I have to figure out what `p` stands for.

`p` stands for "the process in question".

I like to think of single-character vars as idea or topic headers that track the single thing I'm currently up to. I'm rarely working with more than one at a time, frequently it's the only variable, and there are contexts where I wouldn't use them at all.

IMHO if you're in a situation where `p` isn't obvious to you, "something has gone wrong".

This is a decent reason, but your original comment is dangerously close to a completely strawman argument of "the argument of the func AverageAge(people []Person) should be called peopleToCalculateTheAverageOfTheirAges because what if I forget the method's name or its purpose while I am reading its text?"

Which, now that I think of it, kinda applies to your argument as well. Yeah, the debugger dropped you into the middle of a function you see for the first time in your life. No matter how you dice it or slice it, this means you'll have to study this function; I personally find that going to the function's beginning and skimming it until the breakpoint is the most reliable (and therefore, on average, fastest) method.

I don't deny the trade-off between variable name length and other factors. But, between 1 and 38, I doubt that the optimal length is at 1. Adding 5 more letters doesn't take anything away, IMHO, while increasing comprehensibility significantly.

> Wisdom I received from, IIRC, the Perl documentation decades ago

Perl is a language renowned for being difficult to read and maintain.

Tell us about your concrete experience of development in Perl.

'x' is an operator

But what if your codebase has to interact with leads, customers, and another 3rd party system called Metrica with leads, customers?

When you write a loop, do you now name the variable

OurPerson.Age MetricaPerson.Age

What if, 3 years from now, you include another 3rd party vendor into the system and have to write code against that data and in the data they name their stuff OurPerson.Age?

Not saying you are wrong at all. Just naming things is hard and context dependent. I think that is why it is endlessly argued.

This comes from some dated idea for stuff like C where "its okay to use shorthands for variables" but is it really? The only place I allow it is simple iterators, but now we have enhanced loops where even this is unnecessary. We don't need to save on pixel screen space like if its still the 90s. Even with a simple 1080p monitor you can fit plenty of words and code.

Give your variables, functions, classes meaningful descriptive names that make sense to humans.

As creators of Go have strong ties with the creators of C, that idea is not so dated.

Just because some brought it back to modern languages, doesn't mean it's not rooted in a practice from constrained hardware. I'd rather we name things what they mean.

I was surprised to see literally invalid names in the "bad" section, e.g. "Cannot start with a digit". Why even presenting this if it's rejected by the compiler?

The example with the dash in it confused me as well.

I wondered if you could sneak in some unicode digit but it seems to reject those too:

    $ go run z.go
    # command-line-arguments
    ./z.go:6:2: identifier cannot begin with digit U+0661 '١'
    ./z.go:7:27: identifier cannot begin with digit U+0661 '١'

(I tried a few of them but not all.)

"Chat, generate me a table of bad Golang making practices"

Author here. The answer is because I mentioned it as one of the bullet pointed hard-rules, and I wanted to include an example to illustrate it.

Allowing Unicode characters, then stating best practice is to stick with ASCII, is weird. (Go is not alone in this practice.) Unicode identifiers have a host of issues, such as some characters have no case distinction, some have title-case but not uppercase, some "capitalize" the last letter in a word and not the first (Hebrew has five "final form" letters), etc. Does Go specify the meaning (exported or not) if a letter has no case, or if an identifier starts with a zero-width joiner character? Without a huge list of detailled rules, too much is left to the implementation to decide. I prefer to stick with ASCII for names.

Fun fact: When printing with movable type began, printers would travel with large "type cases" containing the small wood or metal blocks with glyphs on them. The ones the used frequently were kept in the lower half of the case, in easy reach. That's where the terms "lowercase" and "uppercase" come from.

it is weird, especially for Go with its semantic naming and famously opinionated compiler. it will gladly build code with a variable named 𖤐界ᥱᥲΣ੭, but God forbid it's unused.

It’s bad to disallow non-ASCII characters when programming for non-English business domains. The domain vocabulary often doesn’t translate well to English, or you need a glossary for someone familiar with the business domain to know which English term is supposed to mean which native business term. It’s just a pain. Conversely, transliterating the native term in ASCII can introduce ambiguities or be awkward or just plain weird for the native speaker.

Of course, Unicode can be abused, but ASCII isn’t completely free of that either. (Maybe it tickles your fancy to name a variable _o0O0o_ or l1lIl1lIl1lIl1l.) If your native script doesn’t have upper and lower case, compromises may have to be made. We have to trust programmers to use good judgement.

I believe https://imgur.com/dN9Nz3h is the canonical example of why full Unicode support is maybe not desirable.

because ths is so much better:

    class pppp {
        func ppp(_ c: Int, m: Int) -> Int {
            return c + m
        }
    }
    
    var b = 3
    var s = b + 2
    
    var p = pppp()
    print(p.ppp(b, m: s))

Anecdotally I'm programming for non-English business domains in Go and Python and I've literally never seen anyone use native alphabet in identifiers - it's always either poor translations or transliterations.

I like this article — short, accurate (which is somehow not a given these days...) and useful, just like Go language itself.

Another of mine: don't name a struct after an interface method that it's supposed to implement. If you have a package linearalgebra, then making a custom error type linearalgebra.LinearAlgebraError is too "chatty" but linearalgebra.Error will cause you pain if it implements "Error string()", as it probably should, and you decide to make a linearalgebra.MatrixSingularError that wraps a linearalgebra.Error to "inherit" its methods.

In the end, it ended up called linearalgebra.Err .

P.S Alex Edwards' "let's go" and "let's go further" are great books to get someone up to date with golang, just keep an eye on features that are newer than the book(s).

The booms receive regular updates. I got an email about an update to Let’s Go Further on 3/12 for Go 1.26

People have been arguing this stuff since the dawn of (computer) time. I don't get it. I've been at it so long now, IDGAF what or how you name something. Short names in loops? Long? I don't care. I really don't. Just be consistent in what you decide and I can read it.

All this arguing... FFS, go DO something with your time!

EDIT: Oh, yeah, as for the article itself, it's a good article. But again, just be consistent in what you choose.

This is great! My team started using Go last year so I fed this article to set off a fleet of agents on our Go codebase and generate a report out w/ code samples based on it. Ended up with a pretty good little document to present on Monday :)

Why do you need AI agents for this?

You either catch and enforce it with a linter (e.g. https://golangci-lint.run/docs/linters/configuration/#revive) (in which case you don't need AI to tell you the current state, you just add the same config to all projects) or you don't enforce it (because everyone will forget unless it's automated)

Using a linter doesn't get you noticed by leadership and net you a promo.

Sure it does, just say you "established org-wide coding standards and drove adoption of automated linting tooling, reducing review friction and enforcing style consistency at scale" in your assessment.

Better yet, post about it on LinkedIn and explain what it taught you about marriage proposals!

one rando set of opinions. stopped reading fast

> Words that are acronyms or initialisms (like API, URL or HTTP) should use a consistent case within the identifier. So, for example, apiKey or APIKey are conventional, but ApiKey is not. This rule also applies to ID when it is used as shorthand for the words "identity" or "identifier" — so that means write userID rather than userId.

Outdated.

Over time, it's become clear that breaking the camelCase convention in this manner is inappropriate:

- The inconsistency with the convention is jarring, consider `APIURL` - is that a variable (ApiUrl) or a constant (APIURL)?

- The inconsistency introduces doubt on how to write any given identifier - which is why the above advice even needs to exist

- The whole point of the convention is to make separate parts of the name visually separate, consider `someAPIURLHTMLJSONExtension` vs `someApiUrlHtmlJsonExtension`

- It's hard to keep this consistent - we may reasonably disagree whether `ID` should be capitalized or not, meaning you may just as well find both `ID` and `id` across codebases. This erases the benefits of capitalization altogether.

The benefits of keeping these acronyms capitalized are dubious and don't outweigh the downsides.

And of course, the real solution is to use the one correct naming convention - `snake_case`. Then you can capitalize all you want without trouble - `some_API_URL_HTML_JSON_extension`.

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