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Meta comment. Something I've wondered of late. I keep seeing these articles pop up and they're trying to recreate ADTs for Python in the manner of Rust. But th

by jghn 2y ago

Meta comment. Something I've wondered of late. I keep seeing these articles pop up and they're trying to recreate ADTs for Python in the manner of Rust. But there's a long history of ADTs in other languages. For instance we don't see threads on recreating Haskell's ADT structures in Python. Is this an artifact of Rust is hype right now, especially on HN? As in the typical reader is more familiar with Rust than Haskell, and thus "I want to do what I'm used to in Rust in Python" is more likely to resonate than "I want to do what I'm used to in Haskell in Python"? At the end of the day it doesn't *really* matter as the underlying construct being modeled is the same. It's the translation layer that I'm wondering about.

steveklabnik 2y ago
I think "hype" has some connotations that I wouldn't necessarily agree with, and I don't think it's as much "on HN" as "people who write Python," but I would agree that I would expect at this point more Python folks to be familiar with Rust than Haskell, and so that to be the reason, yes.
- jghn 2y ago
  The reason I said hype is that it's a cycle here. If you go back 10 years every example *would* have been in Haskell. Or perhaps Scala. They were the cool languages of the era. And the topics here painted a picture that their use in the broader world was more common than they really were. And I say that as someone who used both Haskell & Scala in my day job at the time. HN would have you believe that I was the norm, but I very much was not. That's not to say it's bad, or a problem. If it gets more people into these concepts that's great.
woodruffw 2y ago
(Author of the post.) I think so, in the sense that Rust has successfully translated ADTs and other PLT-laden concepts from SML/Haskell into syntax that a large base of engineers finds intuitive. Whether or not that’s hype is a value judgement, but that is the reason I picked it for the example snippet: I figured more people would “get” it with less explanation required :-)
- jghn 2y ago
  Got it. It makes sense and was what I figured is the case. I find it interesting as it's a sign of the times watching the evolution of what the "base language" is in threads like this over time. I mentioned in another comment that several years ago it'd have been Haskell or Scala. If one went back further (before my time!) it'd probably have been in OCaml or something.
  - mattarm 2y ago
    In my experience learning a bit of OCaml after Rust, and then looking at Haskell, the three aren't all that different in terms of the basics of how ADTs are declared and used, especially for the simpler cases.
    - jghn 2y ago
      Agreed. As a concept they're all the same thing. Another way of phrasing my query is that given these are all basically ML-style constructs, why would the examples not be ML? And I was assuming the answer to that is "the sorts of people reading these blogs in 2024 are more familiar with Rust"
      - runeblaze 2y ago
        I think a second reason might be that translating OCaml/Haskell concepts to Python has that academic connotation to it. Rust also (thanks to PyO3) has more affinity to Python than the ML languages. I guess it isn't a surprise that this post has Python, C++, and Rust, all "commonly" used for Python libraries.
- pwm 2y ago
  Apologies for my meta-meta-comment :) I've been writing code for ~30 years in various languages, and today my brain can't compute how people find any syntax other than this more intuitive: data Thing = ThingA Int | ThingB String Bool | ThingC To me, the above syntax takes away all the noise and just states what needs to be stated.
darby_nine 2y ago
Is there any reason why you've singled out Rust as particularly notable here and not any of the many other languages with them? OCaml, Elm, F#, Scala, I think more recent versions of Java, Kotlin, Nim, TypeScript, and Swift all support ADTs. Python already supports them, albeit with very little runtime support. Rust doesn't particularly stand out in such a broad field of languages. They're so useful a language needs a good reason these days to not support them.
- jghn 2y ago
  You're making the exact point that I was raising.
  - darby_nine 2y ago
    I'm sorry, I'm still completely confused where rust came from or what particular relevance it has to the conversation beyond the short segment in the article? My point being—you see articles about ADTs involving non-rust languages all the time. Why single rust out?
pjmlp 2y ago
It is quite common to see people in Rust circles mentioning Rust being innovative for feature XYZ, that was initially in a ML variant, Ada, Eiffel, .... I would say familarity, and lack of exposure to programming languages in general.
- woodruffw 2y ago
  Nowhere in this post or in any Rust community post I'm aware of does anybody claim that sum types (or product types, or affine/linear types, etc.) are a Rust novelty. As a stretch, I've seen Rust content where people claim that Rust has successfully popularized a handful of relatively obscure PLT concepts. But this is a much, much weaker claim than Rust innovating or inventing them outright, and it's one that's largely supported by the size of the Rust community versus the size of Haskell or even the largest ML variant communities. (I say this as someone who wrote OCaml for a handful of years before I touched Rust.)
  - pjmlp 2y ago
    Where did I specially mentioned it was this post, and not in general? Here is another common one, "It would be great a Rust like but with GC".
    - woodruffw 2y ago
      > Here is another common one, "It would be great a Rust like but with GC". What in this phrase suggests or implies that Rust has innovated something that an earlier FP language actually did? Something that resembles Go's managed runtime but with Rust's sum types seems like a very reasonable thing to want, and doesn't exist per se without buying either into a very foreign syntax and thus a much smaller community and library ecosystem. (Or as another phrasing: what is actually wrong with someone saying this? Insufficient credit given to other languages? Do people apply this standard to C with BCPL and ALGOL? I haven't seen them do so.)
      - jghn 2y ago
        > Something that resembles Go's managed runtime but with Rust's sum types ..... Or as another phrasing: what is actually wrong with someone saying this? I don't think there's anything wrong per se. Although I do think it contributes to the sentiment that people may be ascribing things as being novel to Rust, even when not intended as in this case. To be fair, that's what sent me down the mental path earlier that prompted this subthread. And that's when I figured it was more a matter of being the implementation most likely to resonate with the audience. And I don't think it's a matter of needing to give credit to other languages. But phrasing it like "Something with a managed runtime, but with sum types" is generic enough, unless there's something specific about either of those. For instance the phrasing I gave does exist in plenty of places, but perhaps "Something that resembles Go's managed runtime with sum types" perhaps does not. I don't know enough about Go to say that. In other words, is there something specific about *Rust*'s sum types that one is after in this example? Or just the concept of sum types.
myvoiceismypass 2y ago
FWIW I seem to often find myself reaching for Haskell-isms when writing Typscript or Scala. And I’ve never actually written production Haskell code! But so many concepts like this just map nicely. “Parse don’t validate”, “make illegal states unreprsentable”, etc - all those patterns.
- pjmlp 2y ago
  Also known as Type Driven Development, a much better approach than the other TDD abbreviation.

by jghn 2y ago

steveklabnik 2y ago

I think "hype" has some connotations that I wouldn't necessarily agree with, and I don't think it's as much "on HN" as "people who write Python," but I would agree that I would expect at this point more Python folks to be familiar with Rust than Haskell, and so that to be the reason, yes.

jghn 2y ago
The reason I said hype is that it's a cycle here. If you go back 10 years every example *would* have been in Haskell. Or perhaps Scala. They were the cool languages of the era. And the topics here painted a picture that their use in the broader world was more common than they really were. And I say that as someone who used both Haskell & Scala in my day job at the time. HN would have you believe that I was the norm, but I very much was not. That's not to say it's bad, or a problem. If it gets more people into these concepts that's great.

woodruffw 2y ago

(Author of the post.) I think so, in the sense that Rust has successfully translated ADTs and other PLT-laden concepts from SML/Haskell into syntax that a large base of engineers finds intuitive. Whether or not that’s hype is a value judgement, but that is the reason I picked it for the example snippet: I figured more people would “get” it with less explanation required :-)

jghn 2y ago
Got it. It makes sense and was what I figured is the case. I find it interesting as it's a sign of the times watching the evolution of what the "base language" is in threads like this over time. I mentioned in another comment that several years ago it'd have been Haskell or Scala. If one went back further (before my time!) it'd probably have been in OCaml or something.
- mattarm 2y ago
  In my experience learning a bit of OCaml after Rust, and then looking at Haskell, the three aren't all that different in terms of the basics of how ADTs are declared and used, especially for the simpler cases.
  - jghn 2y ago
    Agreed. As a concept they're all the same thing. Another way of phrasing my query is that given these are all basically ML-style constructs, why would the examples not be ML? And I was assuming the answer to that is "the sorts of people reading these blogs in 2024 are more familiar with Rust"
    - runeblaze 2y ago
      I think a second reason might be that translating OCaml/Haskell concepts to Python has that academic connotation to it. Rust also (thanks to PyO3) has more affinity to Python than the ML languages. I guess it isn't a surprise that this post has Python, C++, and Rust, all "commonly" used for Python libraries.
pwm 2y ago
Apologies for my meta-meta-comment :) I've been writing code for ~30 years in various languages, and today my brain can't compute how people find any syntax other than this more intuitive: data Thing = ThingA Int | ThingB String Bool | ThingC To me, the above syntax takes away all the noise and just states what needs to be stated.

darby_nine 2y ago

Is there any reason why you've singled out Rust as particularly notable here and not any of the many other languages with them? OCaml, Elm, F#, Scala, I think more recent versions of Java, Kotlin, Nim, TypeScript, and Swift all support ADTs. Python already supports them, albeit with very little runtime support. Rust doesn't particularly stand out in such a broad field of languages. They're so useful a language needs a good reason these days to not support them.

jghn 2y ago
You're making the exact point that I was raising.
- darby_nine 2y ago
  I'm sorry, I'm still completely confused where rust came from or what particular relevance it has to the conversation beyond the short segment in the article? My point being—you see articles about ADTs involving non-rust languages all the time. Why single rust out?

pjmlp 2y ago

It is quite common to see people in Rust circles mentioning Rust being innovative for feature XYZ, that was initially in a ML variant, Ada, Eiffel, .... I would say familarity, and lack of exposure to programming languages in general.

woodruffw 2y ago
Nowhere in this post or in any Rust community post I'm aware of does anybody claim that sum types (or product types, or affine/linear types, etc.) are a Rust novelty. As a stretch, I've seen Rust content where people claim that Rust has successfully popularized a handful of relatively obscure PLT concepts. But this is a much, much weaker claim than Rust innovating or inventing them outright, and it's one that's largely supported by the size of the Rust community versus the size of Haskell or even the largest ML variant communities. (I say this as someone who wrote OCaml for a handful of years before I touched Rust.)
- pjmlp 2y ago
  Where did I specially mentioned it was this post, and not in general? Here is another common one, "It would be great a Rust like but with GC".
  - woodruffw 2y ago
    > Here is another common one, "It would be great a Rust like but with GC". What in this phrase suggests or implies that Rust has innovated something that an earlier FP language actually did? Something that resembles Go's managed runtime but with Rust's sum types seems like a very reasonable thing to want, and doesn't exist per se without buying either into a very foreign syntax and thus a much smaller community and library ecosystem. (Or as another phrasing: what is actually wrong with someone saying this? Insufficient credit given to other languages? Do people apply this standard to C with BCPL and ALGOL? I haven't seen them do so.)
    - jghn 2y ago
      > Something that resembles Go's managed runtime but with Rust's sum types ..... Or as another phrasing: what is actually wrong with someone saying this? I don't think there's anything wrong per se. Although I do think it contributes to the sentiment that people may be ascribing things as being novel to Rust, even when not intended as in this case. To be fair, that's what sent me down the mental path earlier that prompted this subthread. And that's when I figured it was more a matter of being the implementation most likely to resonate with the audience. And I don't think it's a matter of needing to give credit to other languages. But phrasing it like "Something with a managed runtime, but with sum types" is generic enough, unless there's something specific about either of those. For instance the phrasing I gave does exist in plenty of places, but perhaps "Something that resembles Go's managed runtime with sum types" perhaps does not. I don't know enough about Go to say that. In other words, is there something specific about *Rust*'s sum types that one is after in this example? Or just the concept of sum types.

myvoiceismypass 2y ago

FWIW I seem to often find myself reaching for Haskell-isms when writing Typscript or Scala. And I’ve never actually written production Haskell code! But so many concepts like this just map nicely. “Parse don’t validate”, “make illegal states unreprsentable”, etc - all those patterns.

pjmlp 2y ago
Also known as Type Driven Development, a much better approach than the other TDD abbreviation.