5 ms·

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.

Patrickmi 3y ago
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
pjmlp 3y ago
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.
- mseepgood 3y ago
  Sounds like a good design guideline, so I wouldn't call it unfortunate.
  - Conlectus 3y ago
    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”.
  - kaba0 3y ago
    Especially when they will eventually have to walk back on their decisions a few years later, see generics..
    - foldr 3y ago
      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.
      - kaba0 3y ago
        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!
        foldr 3y ago
        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.
    - mseepgood 3y ago
      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.
      - Mawr 3y ago
        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 https://github.com/golang/go/discussions/48287
    - Patrickmi 3y ago
      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 https://go.dev/blog/survey2022-q2-results
      - kaba0 3y ago
        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.
        lanstin 3y ago
        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()
      - ilyt 3y ago
        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.
        Patrickmi 3y ago
        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
      - coldtea 3y ago
        >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
  - ilyt 3y ago
    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
  - coldtea 3y ago
    Parent was being sarcastic. Those are basic concepts, already familiar to millions of Java, C# and other programmers...
bsaul 3y ago
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.
eru 3y ago
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.
- wwalexander 3y ago
  I think Wadler also helped out on Java generics.
- nextaccountic 3y ago
  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-195c7321a7f2 https://kranfix.medium.com/pattern-matching-in-golang-195c73...
  - eru 3y ago
    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?
    - nextaccountic 3y ago
      Yes, pattern matching (with destructuring) would be a small addition to the language, and it would be awesome, even without sum types

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

pjmlp 3y ago

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.

mseepgood 3y ago
Sounds like a good design guideline, so I wouldn't call it unfortunate.
- Conlectus 3y ago
  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”.
- kaba0 3y ago
  Especially when they will eventually have to walk back on their decisions a few years later, see generics..
  - foldr 3y ago
    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.
    - kaba0 3y ago
      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!
      - foldr 3y ago
        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.
  - mseepgood 3y ago
    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.
    - Mawr 3y ago
      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 https://github.com/golang/go/discussions/48287
  - Patrickmi 3y ago
    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 https://go.dev/blog/survey2022-q2-results
    - kaba0 3y ago
      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.
      - lanstin 3y ago
        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()
    - ilyt 3y ago
      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.
      - Patrickmi 3y ago
        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
    - coldtea 3y ago
      >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
- ilyt 3y ago
  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
- coldtea 3y ago
  Parent was being sarcastic. Those are basic concepts, already familiar to millions of Java, C# and other programmers...

bsaul 3y ago

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.

eru 3y ago

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.

wwalexander 3y ago
I think Wadler also helped out on Java generics.
nextaccountic 3y ago
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-195c7321a7f2 https://kranfix.medium.com/pattern-matching-in-golang-195c73...
- eru 3y ago
  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?
  - nextaccountic 3y ago
    Yes, pattern matching (with destructuring) would be a small addition to the language, and it would be awesome, even without sum types