6 ms·

A new Erlang VM with just replicated functionality is a fairly hard sell to the Erlang/Elixir community, who brag with the industrial track record of the BEAM.

• themgt 6y ago
  If the VM is in Rust could it be compiled to WASM?
  • rkangel 6y ago
    You wouldn't want to, for various reasons. See this blog post about Lumen and the decision decisions: https://tylerscript.dev/bringing-the-beam-to-webassembly-with-lumen https://tylerscript.dev/bringing-the-beam-to-webassembly-wit...
    • hobofan 6y ago
      You wouldn't want to _right now_. However for almost all points there is a solution underway/in planning. In a year or two it might be feasible. There would however be other limitations, like filesystem APIs etc. not being available in the browser that a lot of frameworks in BEAM languages expect, that would severely limit the usefulness, though I guess that applies to either implementation strategy.
      • dnautics 6y ago
        I think the point though is that architecturally there are performance hits if you don't respect the fact that WASM has a different architecture than what the BEAM expects (harvard vs von neumann IIRC), so you may NEVER want to if you get it right in the first place.
        • wahern 6y ago
          The Harvard-Von Neumann dichotomy is wrong. C also works perfectly fine on Harvard architectures--it's why function pointers in C are special, aren't guaranteed to be convertible to a void pointer, and why uintptr_t is optional. POSIX adds these additional guarantees to support dlsym, which returns function addresses as void pointers. The problems with compiling other languages to Web Assembly are primarily 1) lack of goto and 2) inability to instantiate and jump between different stacks. These limitations are especially problematic for languages like Erlang/BEAM and Go because Web Assembly-based VM implementations require an extra level of indirection in order to implement some of their core language semantics, resulting in quite slow performance compared to even a pure, strictly compliant C implementation (and presuming the WASM VM itself adds no overheard, which is not actually the case). WASM excluded goto support because it was argued that the relooper algorithm required to translate goto constructs to structured WASM statements was sufficiently capable to cover the vast majority of existing code. And they provided evidence to back up that claim. The flaw in that reasoning is that language implementations and similar niche cases have special needs that application code rarely requires, and in that space constructs like goto are crucial to both simplicity of implementation and performance; the inadequacies of relooper become the norm rather than the exception.
          • dnautics 6y ago
            thanks for the clarification!
      • rkangel 6y ago
        I can't imagine a situation in which it would be acceptable to download an entire (WASM compiled) copy of the BEAM from every new website I visit. Full AOT compilation with dead code elimination seems like a much better fit for minimising that bundle size.
        • derefr 6y ago
          WASM isn't just for the web, though. It's beginning to look a lot like the next "portable ISA" (successor to Pascal's pcode, applet-era JVM bytecode, Google's PNaCl, etc.) Add a progressive web-app to your mobile's home screen—get a cached WASM bundle, for near-native performance of the resulting "app." Download an Electron app—get a WASM bundle wrapped in a projector. Even then, there are still browser use-cases where "full fat" apps are no problem. The "apps" in the Chrome Web Store—Adobe has a version of Photoshop in there, I think—make a lot of sense to be WASM. You'll launch them once and keep them open for hours.
• archseer 6y ago
  Yeah I definitely didn't see it being production ready any time soon, but I thought it was an interesting project for people that wanted to learn BEAM internals. That's how I got started with it at least, I had problems trying to contribute BEAM just because of the sheer size of the codebase and lacking the domain specific knowledge. I do think that having alternative implementations is good for experimentation though, similar to how Ruby was improved upon ideas from JRuby and Rubinius, even if most users never used those two directly.
  • bsder 6y ago
    > That's how I got started with it at least, I had problems trying to contribute BEAM just because of the sheer size of the codebase and lacking the domain specific knowledge. And the fact that a LOT of BEAM was terribly undocumented. I'm impressed you got anywhere, personally. The last time I looked at BEAM to understand some weird behavior (that eventually did turn out to be a problem in Erlang/BEAM), it was completely impenetrable. Your implementation is probably useful as documentation, if nothing else.
    • bitwalker 6y ago
      100%, when I started building Lumen, I spent an enormous amount of time working out how various parts of the BEAM runtime were implemented, and it was (and still is sometimes) a grind. That macro-heavy C code is just such a bear to read. I understand why it was written that way, but working with it is just unpleasant. Having Enigma, and other implementations like it, provides a huge value in terms of understanding how it all fits together - understanding the Enigma implementation and then going and trying to make sense of the BEAM would probably be a way better path than trying to dive into the BEAM straight away.
• dnautics 6y ago
  Someday this is going to need to happen though. IMO, "the right way" to do this is via the strangler pattern: https://www.michielrook.nl/2016/11/strangler-pattern-practice/ https://www.michielrook.nl/2016/11/strangler-pattern-practic... Probably the language that is most poised to achieve this is Zig; it would be feasible to start by wrapping the entire BEAM in a zig compilation unit; which at the very least potentially offers an easier path to maintaining the codebase across multiple platforms. Followed by hodgepodge doing bits and pieces in zig, which could be achieved via straightforward transliteration at first. The very different mindset of the rust PL lends itself to total rewrites, which I don't think will sit well in the BEAM community. On the other hand erlang has tons of strange rewrites happening over its own internal ecosystem all the time (gen_fsm -> gen_statem, pg -> pg2 -> pg), etc.
  • muizelaar 6y ago
    Do you know of any examples of this being done with Zig? I can think of a couple with Rust: - https://gitlab.gnome.org/GNOME/librsvg https://gitlab.gnome.org/GNOME/librsvg completed a migration to Rust. - https://github.com/RazrFalcon/rustybuzz https://github.com/RazrFalcon/rustybuzz and https://github.com/immunant/rexpat https://github.com/immunant/rexpat are making decent progress.
    • dnautics 6y ago
      No, because zig is still in 0.6.0, and the BDFL says "don't use this in prod yet"? Yeesh.
      • catach 6y ago
        Perhaps then, for the sake of setting those expectations, the wording "the language that may be most poised to achieve this in the future is Zig" would be preferred?
        • dnautics 6y ago
          Last I checked "poised to achieve this" implies the future. Moreover I have specific reasons to say that, namely that zig now ships with C compilation with transparent cross-compilation support so you can use it as a direct replacement for C and (I believe make), so the statement is based on current zig features whose importance I alluded to in the comment. Fwiw this is also a real problem as I am often hearing complaints about windows ABI support in elixir, anyways. Moreover, having written nifs, I have to say the c header for nifs is basically unintelligible without manually parsing the DEFINES because of windows cross-support needs. Please let me know if I'm using "poised" incorrectly.
• fortran77 6y ago
  We do a lot of Erlang work here. The BEAM is so reliable that I wouldn't spend 1 minute looking at an experimental alternative.
  • carapace 6y ago
    Yeah, this. I'm just getting started with Erlang and I already feel like an idiot for not using it sooner. When I think of some of the things I've done to try to achieve what the BEAM does out-of-the-box...
    • rhlsthrm 6y ago
      Can you give some examples? I've been getting more and more interested in Erlang.
      • battery_cowboy 6y ago
        RPC is basically built in, so you'll probably never use REST internally. There's an in memory database built in (ETS) that will replace redis for most key value storage cases. There's easy recovery from crashes via supervision trees and associated features. You can do hot upgrades while your system is fully operational.
        • dnautics 6y ago
          A few protips: hot reloads are outside of a few corner cases generally unnecessary these days. Be careful about erlang rpc if you expose it in any fashion over the network and follow the eef security working group guidelines re: erlang term format. I use Elixir's plug.crypto.non_executable_binary_to_term/2
          • battery_cowboy 6y ago
            Thanks, I knew both of those bits of info, but I didn't know about the guidelines and how to deal with the RPC issue, very helpful.
• conradfr 6y ago
  There is some go projects like [1] that can connect to Erlang nodes and claim to be speedier. [1] https://github.com/halturin/ergo https://github.com/halturin/ergo
• jlg23 6y ago
  Just being able to amend job requirements with "or rust experience" is most probably worth it.