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Comment by bsaul | Hacker News Reader

Coming from swift, it's pretty refreshing to see a language that has decided to settle on the language itself pretty early and focused on improving all other aspects of the dev experience.

Last time i ran my go test suite on the CI i thought it had a bug because it was so fast compared to what i'm used to with swift.

I do still have a weird feeling of getting back to the stone age whenever i get a nil pointer panic though. i wish go devs could figure out a way of fixing those last quirks without impacting the rest too much.

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> I do still have a weird feeling of getting back to the stone age whenever i get a nil pointer panic though. i wish go devs could figure out a way of fixing those last quirks without impacting the rest too much.

Unfortunately fixing the "billion dollar mistake" as a retrofit is pretty much impossible without breaking backward compatibility. I see what they were trying for with nil and zero values, but IMO they should have introduced a "result" and "option" special type (or probably more Go-like would be separating nullable and non-nullable types via '?' like Dart did). If they did it like Dart, they could intro the concept without breaking backwards compatibility, wait X years until mostly adopted everywhere, and THEN break backwards compatibility by making it mandatory.

They should have introduced sum-types. Or in C term: tagged unions that are checked by the compiler.

They did the opposite when they designed the language, with their 'multiple return values', which are like tuples but only allowed in one special position in the language. But as you already suggested, tuples are the exact opposite of the "result" type you'd want here.

I would have much preferred sum types to generics. I can live with rewriting min() or using for loops over iterators or writing my own linked list; it’s a lot harder to safely (and performantly) work with data that can have a fixed set of shapes.

You know how Go had generics for a long time, but only for the language designers who got to use it in functions like `make` or data structures like `map` or `slice`. There didn't used to be any generics for users of the language.

Similarly, Go has tuples, but only for the language designers who get to use them for multiple return values from a function. No tuples to be used elsewhere where users of the language might find them useful.

Now, Go also has sum types. But, yet again, only for the language designers: they get to stick `nil` as one of the constructors (to use Haskell terminology) in their favourite data types, but you as a language user don't get to make new sum types.

Another example is operator overloading: the designers get to overload eg arithmetic operators, but you don't get to do that.

In contrast C++ even for all its other faults at least makes an attempt to hand you many of the tools the language designers get. (Though, I like Rust's and Haskell's approach here more.)

No, the language designers use the same type system as everyone else. Yes, Go had a fixed set of generic data structures, but those were available to everyone.

“Nil” does not a sum type make; it’s just the zero value for a reference type and the type-checker doesn’t check that you are handling nil and non-nil cases as a type-checker would do for sum types (if Go’s pointers are sum types, then integers and floats in any language are sum types as well).

Go has never had operator overloading for the language designers or anyone else. The operators that the language designers use behave the same way as when users use them.

I have a lot of respect for Rust, and I was a C++ developer in a past life, but most of the software I write these days cares a lot more about developer velocity than about eeking out every last bit of performance or correctness, and most of the time Go is the ideal candidate for those sorts of tradeoffs.

Pretty much; sum types would also allow for the other achilles heel of it to be fixed, the overly verbose error handling.

I don't know that you can just add compile time nil checking to go and still retain everything else.

It seems to me - although I could be entirely wrong - that the mindset that produces this kind of idea ("nil pointers are teh devil!") is incapable of producing the kind of experience that Go produces with its toolchain (trivial cross-platform compilation, etc).

Again I can't prove it, but it just seems that way.

For instance, if you believe nil pointers are the devil and you should statically enforce checking them at compile time, it seems that it would only be natural that you would also think the following other things are very important to be enforced at compile time:

- Read-only references

- Move semantics

- And all the related baggage

What does this have to do with compile times and cross compilation? Maybe not much, but time and attention are limited resources, and when you focus on concepts typical related with "nil pointers are evil" you take away precious resources that could otherwise have been dedicated to building the kind of developer experience that Go provides.

I really don’t understand why you got downvoted. That’s also my explanation of why they did it this way (which i don’t agree with, but they built a PL, i didn’t).

Lots of languages have checked-nils without all the other stuff. TypeScript is one, Zig is another, Kotlin is another

Zig is a good counter example to my argument, but there are things that Go does that Zid does not, namely, a runtime to manage:

- Goroutines

- Garbage collections

I'm not saying these are good or desireable per se.

The point is a bit more general: you can't just accumulate features without this accumulation having other effects on the language and its toolchain and causing degradations in other ways.

Goroutines are the go-to of concurrent programming. A C# task without a handler or modern synchronisation mechanisms.

I wonder why Go doesn't have algebaric data types, it could solve a lot of issues, and make code a lot easier to write.

Unfortunately for the same reason it lacks many other modern features introduced by CLU and Standard ML in the mid-70's, language designers don't want to overburn Go developers with PhD level concepts.

Sounds like a good design guideline, so I wouldn't call it unfortunate.

Algebraic data types (more technically sum types) are very much not “PhD level concepts”, despite the name. They’re just what C developers would call “tagged unions”.

Especially when they will eventually have to walk back on their decisions a few years later, see generics..

They took the time to do it properly with input from experts on type systems (e.g Phil Wadler). The result is probably much better than what we'd have if the Go developers had quickly thrown together an implementation of generics 10-15 years ago. For example, the resulting type system is known to be sound.

Now it may be close to Java’s expressivity, 8 years ago. Now if they manage to cut down on verbosity it might surpass Java 8! How advanced!

Java's generics implementation is certainly much more expressive as it's unsound :)

People can write Java if they prefer. No programming language is going to please everyone.

Not having generics was never a fixed decision. The FAQ said since day one that they "may well be added at some point" and that "The topic remains open", so there was no "walking back".

By the way, not having ADTs is not a fixed decision either.

You seem to mistake the fact that the Go team is in no rush to add things to the language as a general rejection of these things.

It doesn't matter. What does is Go 1.0 shipped without generics. That single decision immutably affected the entire language. Now that generics have been retrofitted, the issues are clear as day:

- Awkward transition period between a stdlib with and without generics: [1]

- Completely different APIs for built-in data structures (slices, maps) and generic ones

- Lack of obvious follow-up features that would have been there at 1.0 if generics were added, e.g. iterators

[1]: https://github.com/golang/go/discussions/48287

Where did you get the information that the Go team never wanted Generics, even the hype around having generics yet the stats shows 50% of Go developers wasn’t interested in it

https://go.dev/blog/survey2022-q2-results

50% of Go developers will never write a library, but they will definitely use one, and for that it is pretty much a must.

We really shouldn’t cater to the average user, as they honestly don’t know what’s good for them.

I am not sure this is true. Every single go project I have seen at work has pkg/ and internal/

If anything, I wish people would have main.go be a bit longer so I can see the main bones of the application but people always like to a := app(conf) ; a.run()

50% of devs interested in feature is pretty high.

Also generics is mostly stuff that make libraries more convenient, not average user code. It also reduces bugs where otherwise interface{} and type checking would be used.

If you compare the amount of attention, language bashing, dedication and sweat being put in it I should expect the survey to show at least 75% adoption

>Where did you get the information that the Go team never wanted Generics

By them acting as if they never wanting Generics, not having Generics from day zero, delaying their implementation for a decade with BS excuses, pretending they are some kind of unsurmountable problem....

They were literally pressureed into getting them in, after years of resistance, when they recognized the mess they've made

Of course you can make up your own little head canon about their motives but it has nothing to do with reality.

The only compatible headcanon for their thoughts on the issue is the above though. Not sure where the "reality" comes from.

Rob Pike explicitly stated that he really isn't into generics,

https://youtu.be/RIvL2ONhFBI?t=1018 (starts here)

https://youtu.be/RIvL2ONhFBI?t=1892 (he expresses his opinion here)

We haven't made our little heads out of nowhere.

I have watched this talk back then when it came out, and I just rewatched the parts you linked. Nowhere in this talk he said that he isn't into generics. He said that he is not yet satisfied with design drafts (that existed at that time), and that he would like to bring in experts. Which he did, when he asked Phil Wadler to join, which led to the current design. The talk is actually proof that he was and is open to generics. "If we can implement these and learn about it a lot of what becomes important will clarify and something will come out of it, maybe something wonderful." Again, you make up some warped interpretation in your head.

And over that period, not a single person put forward a viable and fully worked-up proposal for how generics should work in Go. It's almost as if programming languages aren't developed by anonymous people complaining on the internet.

>And over that period, not a single person put forward a viable and fully worked-up proposal for how generics should work in Go.

That was the official excuse (while each and every proposal coming in was shot down, just to get.a sub par, half-thought, Generics implementation, full of sui generis and NIH details implementation.

It's not rocket science, there are 100s of languages with Generics, including languages with many orders of magnitude more than the adoption Go has.

Which proposal would you rather had been adopted instead?

It's strange to describe the current implementation has "half thought". A lot of work was done to make sure it was correct: https://arxiv.org/pdf/2005.11710.pdf It's probably one of the most carefully thought through generics implementations in a mainstream programming language.

>It's not rocket science, there are 100s of languages with Generics, including languages with many orders of magnitude more than the adoption Go has.

It's easy to add generics but not so easy to get it right (see e.g. Java's soundness issues, the total mess of C++ templates). Rust's generics also have some dark corners (e.g. https://github.com/rust-lang/rust/issues/84857).

There’s nothing stopping language maintainers implementing a feature if you really hate the slow and thoughtful journey then the language isn’t meant for your “ideal programming language”

I sympathise with the idea but I do think they put the line in the sand too close. Go that had generics and sum types from the start would be my near-perfect GC-ed language

Parent was being sarcastic. Those are basic concepts, already familiar to millions of Java, C# and other programmers...

That’s also my question. ADT seems really to fit well with the no-class no-inheritance design that go took. I don’t see how it would affect the language in any major way. But then, i’m not an expert.

The design philosophy is what makes a programming language, any language maintainers could one day decide to have any of these, when you begin to understand “why this is language existed” you begin to understand its purpose

My speculation: the authors didn't know / understand algebraic data types.

Also, to make algebraic data types useful, you really want parametric polymorphism. But yet again, the others of Go weren't familiar with this. The only vaguely related technique they knew about were C++ templates, and they (reasonably!) decided that they didn't want C++ template hell in their language.

That last part about templates is the least speculative of the bunch: I read some of the discussion they had about generics, and they explicitly mentioned templates (and how complicated they are) and pretty much mentioned nothing else for how to design or implement generics.

Go recently got some generics, partially thanks to some help from Phil Wadler who's otherwise more known for his work in functional programming.

I think Wadler also helped out on Java generics.

To make adts / sum types useful you really need pattern matching with destructuring, which Go appears to lack

https://kranfix.medium.com/pattern-matching-in-golang-195c73...

You can use sum types without pattern matching and vice versa, but you are absolutely right that they synergies well.

I don't know enough about Golang: do you know whether it's possible to add pattern matching with destructuring as a fairly shallow syntactic sugar?

Generics were a much bigger change to the underlying language (and so would be Rust-like lifetimes, or even immutability); but pattern matching seems like something that should be relatively easy to add with only local repercussions?

Yes, pattern matching (with destructuring) would be a small addition to the language, and it would be awesome, even without sum types

Python had that kind of pattern matching for ages, but only recently got pattern matching on something like sum-types.

I only found that previous kind of pattern matching useful occasionally. But I guess I would miss it a lot, if it was gone?

In this regard Go has been the exact opposite of Rust.

Isn’t the Rust DX pretty good still?

Rust has very long compile time compared to Go

Rust could also have shorter compile times, if it gave up on a lot of the optimizations and features it currently does.

A massive source of compilation pain is that Rust just generally generates a lot of code - it always prefers specialization over dynamic dispatch unless the source specificies dynamic dispatch. Couple this with a culture of believing dynamic dispatch is always worse and lots of codegen for generics and you get one hell of a task for your linter. I wouldn't call this an optimization, but rather an almost cultural design decision.

It’s more correct to say that it always prefers zero-cost abstractions. Defaulting to dynamic dispatch would go very much against this, even if in some cases it’s not a bad idea.

Most of the code is cold. Spending compile time on that probably isn’t worth it. As such it’s not a zero cost abstraction (yes yes - it normally means runtime but still - developer time is important too and that’s where the trade off is).

In most cases static dispatch is faster. In many cases dynamic dispatch can be just as fast (speculation by CPU negates the cost) and in some cases it can be faster (better code density). This 0-cost abstraction principle from c++ is actively harmful because there’s almost no such thing. Performance is such a subtle thing that what’s 0-cost in one scenario is a non 0 cost in others. Also spending compile time on the “dark matter” of code that’s rarely executed is probably not the best way to spend the developer time budget. I want CI to generate fully optimal code for production in release builds. For running tests in presubmit, I probably want a little bit less optimization. For local development I want it to be just fast enough that compile times are quick and I can iterate quickly (except for the cases I’m tuning performance in which case I have no choice but to spend max compilation time).

I strongly doubt that endless fields of cold/dead code are zero-cost, without profile guidance and link-time optimization.

One of my favorite go-to examples for this is "Producing Wrong Data Without Doing Anything Obviously Wrong!" 4.2 where they demonstrate a reproducible >30% performance difference just by "misaligning" stacks with an unused environment variable. That's in the context of unexpected measurement bias, but you won't convince me piles of cold code can't affect memory layout less than that.

I think we’re in agreement. Did you misread what I wrote or did I say/imply the opposite somehow?

I agree, but what you are asking is impossible in the general case. The compiler can’t know what is hot and cold without PGO, and doing dynamic dispatch in development to speed up compilation seems iffy.

Surely a better approach is to use incremental compilation, and only do this expensive stuff potentially only once?

However I do agree with your overall point - dev compilation in rust is too slow.

Meanwhile OCaml and Haskell provide interpreters and REPL to ease the whole development experience.

Nothing prevents Rust of doing the same, other than resources.

evcxr does provide a hacky Rust REPL implementation: https://github.com/evcxr/evcxr

-Emily

Yes, but said REPL just wraps user entered expressions itno a function body and then compiles them to a shared object via cargo - thus the language is interpreted via the slow compiler anyway.

I said hacky, and also parent was talking about the lack of a REPL, not the speed of one.

-Emily

>and you get one hell of a task for your linter

Did you mean 'linker' here?

Yes.

I think the main problem with rust, is that the things they decided to settle on early on (aka the borrow checker) are the ones at the root of all the difficulties. They then tried to tame those issues little by little by improving the language ergonomics.

This is pretty different from swift for example. Which had a sane basis very early on, but decided to expand the language by adding features over features, moving the language to a lot of different directions, turning it into an ugly beast ( i still like it though, but i’m not sure for how long).

Learning to work with Rust's borrow checker leaves one with the sinking realization that every C program also has a borrow checker: The very fallible programmer.

Not just C, any language with mutable aliases references/pointers, which is pretty much every modern language.

https://blog.polybdenum.com/2023/03/05/fixing-the-next-10-00...

Well, Haskell has mutable aliases, references and pointers. But you seldom use them.

At this point in history it should be more or less apparent that "here's a gun you can shoot your foot with, just don't do it lol" is not a viable strategy. It's the strategy of the C devs whose memory safety bugs and buffer overflow mistakes we still find to this day, in a number of popular and very widely used programs.

...Nah. We shouldn't go back (and I am not saying you claim so, I am kind of just developing the thought here). Let's have memory safety and algebraic data types and maybe pluggable GC runtimes (if lifetime management proves too difficult which it has at times; not every task is perfectly suited for Rust's borrow checker) and async, and any other goodies that help us solve real problems, and let's not dream of a simpler life.

That "simpler life" has failed. We should acknowledge that and move on and work with the reality in front of us.

Rust's lifetime management and async runtime(s) can be maddeningly difficult but after being on all parts of the spectrum -- from bash scripts and JS Wild West projects to Rust -- I confidently claim that the more strictness the better.

...Though I wouldn't refuse Rust having compile times like those of Golang and OCaml, can't deny it.

I mostly agree with you.

> At this point in history it should be more or less apparent that "here's a gun you can shoot your foot with, just don't do it lol" is not a viable strategy.

However in the case of Haskell, manually mucking around with mutable aliases, references and pointers is culturally similar to using unsafe in Rust. By default in Haskell you are using immutable variables. And if you have multiple threads and want to share mutable state, you typically use software transactional memory.

> ...Though I wouldn't refuse Rust having compile times like those of Golang and OCaml, can't deny it.

Well, Golang has quick compile times, partially because it makes the human do half of the compiler's job. OCaml is indeed something that's more worth aspiring, too.

As a compromise, I found that `cargo check` is much quicker than a build and does most of what I need when developing: most of the time, I don't actually care about the resulting binary, I just want the compiler to tell me quickly whether I introduced any errors it can detect.

While there are other benefits to the borrow checker, the main one is safe memory management and GC languages get you that much while allowing for faster development.

Can't disagree with you at all, even though I want to.

I love Rust and I hate having to emulate enums in Golang but the speed of development becomes more and more a deal-breaker the more time I spend with Rust.

I might just settle at OCaml, if at all possible. Or, since this is the real life and there are no simple final solutions, I'll likely just become a master of all three.

But really, as much as I appreciate Rust for being super strict, I also don't think strict lifetime management is as important for many tasks (though it's a life-saver for some).

Yeah, I 100% agree with hating emulating enums in Go (particularly because there is no safe way to emulate exhaustiveness checks). Personally I haven’t found Ocaml to be any more productive (inadequate libraries, poor tooling, constant futzing with multiple std libraries), but maybe I didn’t commit to it for long enough?

That said, I’m starting to do a bit more systems development so I’m excited to dabble a bit more in Rust.

gc is about memory disposal. IMHO the main purpose of the borrow checker is to ensure proper concurrent memory access, while the memory is still in use.

Which gc don't help at all..

I don’t think the main purpose is concurrent memory access considering the enormous share of memory managed by the borrow checker which is never accessed in a concurrent context. Whichever purpose is the “main” purpose hardly matters anyway—the fact of the matter is that Rust makes memory management quite burdensome even though it makes it easier to ensure certain correctness properties.

Unfortunately you can't start simple and add lifetimes-as-types into your language, because that's at the very core of it. You'd kill all backwards compatibility with it. There's likely no gradual path to Rust from non-Rust.

I don't follow.that logic: If you can mark sections of Rust unsafe why could language X not allow marking sections of X as "safe"?

Then over time you can use only 3rd party packages that are fully safe (same as has happened naturally with rust but just "not unsafe").

https://doc.rust-lang.org/book/ch19-01-unsafe-rust.html

> It’s important to understand that unsafe doesn’t turn off the borrow checker or disable any other of Rust’s safety checks: if you use a reference in unsafe code, it will still be checked.

Going from the other side would be really hard to design for. The whole standard library in rust is relying on the lifetimes being there. If you started without them you'd end up with things which can't be implemented safely anymore. Even with the lifetimes available, some traits took ages to stabilise and ensure no edge cases. You'd have two standard libraries and the compiler would have to know how to make them interact. Or maybe they couldn't interact and you'd have to remember some hashes have get/set you started with and others need `.entry(...).and_modify(...)`. That sounds terrible for usability.

My guess is this is what swift has planned. They’ve been slowly adding hidden features inside the compiler to detect more and more problematic memory sharing patterns. My hunch is that the two language will eventually converge. Rust slowly improving the ergonomics, and swift slowly adding more safety.

Pretty much the only time I see a nil pointer panic in Go is when a junior dev doesn't initialize a map, which is easy to diagnose and fix (and should probably get a linter). It's a non-issue as far as I'm concerned.

Just don’t write any bugs!

My CTO literally said this one day

They should stop teaching beginners how to write bugs, then nobody would do it because they wouldn't know how.

basically any struct containing pointers can be misinitialized and have nil pointers.

it is indeed quite easy to fix most of the time, but it's also a non-issue in a lot of modern PL.

It's an easy mistake to make regardless of experience.

eh, that’s dumb.

Most go types have useful default value. Nil slice is a 0 length slice. Default byte.Buffer is an empty buffer. Default of struct is all fields default. That’s all great.

Except for map. Which panics. Oops!

It's because appending to a slice returns another slice, whereas assigning a key to a map doesn't return another map. That means that there's no sensible way to assign a key of a nil map. You could make adding a key to a map work like appending a value to a slice, or you could add an extra level of indirection to the underlying map type (make it a pointer to a struct instead of a struct). Neither of those alternatives seems particularly attractive, though.

nil map in Go can be used for reading. It cannot be used for writing only.

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