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Yes, that's how the story goes. Languages with specs are widely deployed despite being fragmented and bad, not because people find value in multiple implementat

by gkbrk 3y ago

Yes, that's how the story goes. Languages with specs are widely deployed despite being fragmented and bad, not because people find value in multiple implementations. Must be a coincidence that C, C++, Javascript and C# and Java all fall under this umbrella.

legobmw99 3y ago
Java and C# seem to have actually gotten the idea of multiple implementations correct, in the sense that I have never needed to worry about the specific runtime being used as long as I get my language version correct. I have basically never seen a C/C++ program of more than a few hundred lines that doesn’t include something like #ifdef WIN32 …
- bluGill 3y ago
  Is there more than one Java implementation that is usable? All I can find are obsolete products that never got very far.
  - gkbrk 3y ago
    Here are a few Java implementations that I've used recently. - My Android phone - OpenJDK on my laptop - leJOS for a university robotics course to run on Lego robots - Smart cards, I have a couple in my wallet Perhaps I'd call the Lego robot stuff obsolete, certainly not the Android userspace or smart cards though.
    - vlovich123 3y ago
      Your Android phone and the latest Java share very little commonality. It only recently supports Java 11 which is 5 years old at this point. The other non-OpenJDK implementations you mentioned are much more niche (I imagine the smart cards run JavaCard which is still probably going to be running an OpenJDK offshoot).
      - gkbrk 3y ago
        Who said anything about the latest Java. Since Java has versioned specs, platform X can support one version, and you can target it based on that information even if other versions come out and get supported by other platforms. For example C89 and C99 are pretty old, and modern C has a lot that is different from them. But they still get targeted and deployed, and enjoy a decent following. Because even in 2024, you can write a new C89 compiler and people's existing and new C89 code will compile on it if you implement it right.
        sunshowers 3y ago
        But as a developer I do want to use (some of) the latest features as soon as they become available. That's why most of my crates have an N-2 stable version policy.
        vlovich123 3y ago
        And since Rust does a release every 6 weeks, we’re talking a ~4 month lag. That’s unheard of for C/C++.
        lanstin 3y ago
        It is the sort of thing that people aimed for in the 90s, when there was more velocity in c and c++. If rust lives long enough the rate of change will also slow down.
        pjmlp 3y ago
        In the 90s if you wanted new features you had to pay for them.
      - pjmlp 3y ago
        Java 17 LTS is supported from Android 12 onwards. PTC, Aicas, microEJ, OpenJ9, Azul, GraalVM are a couple of alternative JVM implementations.
  - hansjorg 3y ago
    Eclipse OpenJ9 (previously IBM J9) is in active development and supports Java 21.
- vintermann 3y ago
  Well, there's Android... and Unity, which as I recall is stuck on an old version of C# and its own way of doing things. I also had the interesting experience of working with OSGI at work a couple of years.
  - pjmlp 3y ago
    And Meadow, and Capcom, and Gotdot 3,
bluGill 3y ago
Or do languages get specs because they are widespread and becoming fragmented? That clearly apples to C and C++ - both were implemented first and then a formal spec was written in response to fragmentation.
vlovich123 3y ago
C# has multiple compilers and runtimes? Mono used to be a separate thing but if I recall correctly mono has been adopted by MS & a lot merged between the two. JavaScript itself is a very simple language with most of the complexity living in disparate runtimes and that there are multiple runtime implementations is a very real problem requiring complex polyfills that age poorly that are maintained by the community. For what it’s worth TypeScript has a single implementation and it’s extremely popular in this community. Java is probably the “best” here but really there’s still only the Sun & OpenJDK implementations and the OpenJDK and Oracle are basically the same if I recall correctly with the main difference being the inclusion of proprietary “enterprise” components that Oracle can charge money for. There are other implementations of the standard but they’re much more niche (e.g. Azul systems). A point against disparate implementations is how Java on Android is now basically a fork & a different language from modern-day Java (although I believe that’s mostly because of the Oracle lawsuit). Python is widely deployed & CPython remains the version that most people deploy. Forks find it difficult to keep up with the changes (e.g. PyPy for the longest time lagged quite badly although it seems like they’re doing a better job keeping up these days). The forks have significantly less adoption than CPython though. It seems unlikely that independent Rust front end implementations will benefit it’s popularity. Having GCC code gen is valuable but integrating that behind the Rust front-end sounds like a better idea and is way further along. gccrs is targeting a 3 year old version of Rust that still isn’t complete while the GCC backend is being used to successfully compile the Linux kernel. My bet is that gccrs will end up closer to gcj because it is difficult to keep up.
- lioeters 3y ago
  > TypeScript has a single implementation It's probably a matter of time until there's a TypeScript compiler implemented in Rust. But the surface area of the language is pretty big, and I imagine it will always lag behind the official compiler. > Forks find it difficult to keep up with the changes That's interesting to think of multiple implementation of a language as "forks" rather than spec-compliant compilers and runtimes. But the problem remains the same, the time and effort necessary to constantly keep up with the reference implementation, the upstream.
  - 3y ago

by gkbrk 3y ago

legobmw99 3y ago

Java and C# seem to have actually gotten the idea of multiple implementations correct, in the sense that I have never needed to worry about the specific runtime being used as long as I get my language version correct. I have basically never seen a C/C++ program of more than a few hundred lines that doesn’t include something like #ifdef WIN32 …

bluGill 3y ago
Is there more than one Java implementation that is usable? All I can find are obsolete products that never got very far.
- gkbrk 3y ago
  Here are a few Java implementations that I've used recently. - My Android phone - OpenJDK on my laptop - leJOS for a university robotics course to run on Lego robots - Smart cards, I have a couple in my wallet Perhaps I'd call the Lego robot stuff obsolete, certainly not the Android userspace or smart cards though.
  - vlovich123 3y ago
    Your Android phone and the latest Java share very little commonality. It only recently supports Java 11 which is 5 years old at this point. The other non-OpenJDK implementations you mentioned are much more niche (I imagine the smart cards run JavaCard which is still probably going to be running an OpenJDK offshoot).
    - gkbrk 3y ago
      Who said anything about the latest Java. Since Java has versioned specs, platform X can support one version, and you can target it based on that information even if other versions come out and get supported by other platforms. For example C89 and C99 are pretty old, and modern C has a lot that is different from them. But they still get targeted and deployed, and enjoy a decent following. Because even in 2024, you can write a new C89 compiler and people's existing and new C89 code will compile on it if you implement it right.
      - sunshowers 3y ago
        But as a developer I do want to use (some of) the latest features as soon as they become available. That's why most of my crates have an N-2 stable version policy.
        vlovich123 3y ago
        And since Rust does a release every 6 weeks, we’re talking a ~4 month lag. That’s unheard of for C/C++.
        lanstin 3y ago
        It is the sort of thing that people aimed for in the 90s, when there was more velocity in c and c++. If rust lives long enough the rate of change will also slow down.
        pjmlp 3y ago
        In the 90s if you wanted new features you had to pay for them.
    - pjmlp 3y ago
      Java 17 LTS is supported from Android 12 onwards. PTC, Aicas, microEJ, OpenJ9, Azul, GraalVM are a couple of alternative JVM implementations.
- hansjorg 3y ago
  Eclipse OpenJ9 (previously IBM J9) is in active development and supports Java 21.
vintermann 3y ago
Well, there's Android... and Unity, which as I recall is stuck on an old version of C# and its own way of doing things. I also had the interesting experience of working with OSGI at work a couple of years.
- pjmlp 3y ago
  And Meadow, and Capcom, and Gotdot 3,

bluGill 3y ago

Or do languages get specs because they are widespread and becoming fragmented? That clearly apples to C and C++ - both were implemented first and then a formal spec was written in response to fragmentation.

vlovich123 3y ago

C# has multiple compilers and runtimes? Mono used to be a separate thing but if I recall correctly mono has been adopted by MS & a lot merged between the two. JavaScript itself is a very simple language with most of the complexity living in disparate runtimes and that there are multiple runtime implementations is a very real problem requiring complex polyfills that age poorly that are maintained by the community. For what it’s worth TypeScript has a single implementation and it’s extremely popular in this community. Java is probably the “best” here but really there’s still only the Sun & OpenJDK implementations and the OpenJDK and Oracle are basically the same if I recall correctly with the main difference being the inclusion of proprietary “enterprise” components that Oracle can charge money for. There are other implementations of the standard but they’re much more niche (e.g. Azul systems). A point against disparate implementations is how Java on Android is now basically a fork & a different language from modern-day Java (although I believe that’s mostly because of the Oracle lawsuit). Python is widely deployed & CPython remains the version that most people deploy. Forks find it difficult to keep up with the changes (e.g. PyPy for the longest time lagged quite badly although it seems like they’re doing a better job keeping up these days). The forks have significantly less adoption than CPython though. It seems unlikely that independent Rust front end implementations will benefit it’s popularity. Having GCC code gen is valuable but integrating that behind the Rust front-end sounds like a better idea and is way further along. gccrs is targeting a 3 year old version of Rust that still isn’t complete while the GCC backend is being used to successfully compile the Linux kernel. My bet is that gccrs will end up closer to gcj because it is difficult to keep up.

lioeters 3y ago
> TypeScript has a single implementation It's probably a matter of time until there's a TypeScript compiler implemented in Rust. But the surface area of the language is pretty big, and I imagine it will always lag behind the official compiler. > Forks find it difficult to keep up with the changes That's interesting to think of multiple implementation of a language as "forks" rather than spec-compliant compilers and runtimes. But the problem remains the same, the time and effort necessary to constantly keep up with the reference implementation, the upstream.
- 3y ago