Hacker News Reader

Comment by dillonb | Hacker News Reader

Well, this is just targeting a different VM, LLVM instead of the JVM. You get easy interop with all LLVM languages with this, including C.

View on HN

You should really check your facts before posting a statement like this.

While the VM in LLVM historically was short for Virtual Machine, it really has nothing to do with that. It's a compiler backend used by Clang (C++ compiler) and Rust.

My understanding is that IR is designed as though there were a VM to run it, but in practice, IR is immediately used to generate code for a target architecture.

That might have been true originally, but I don't think anyone uses LLVM like a JVM/CLR-esque VM any more. As the parent states, the original Low-Level Virtual Machine initialism was even retracted, meaning the project's name is just the "arbitrary" sequence of letters LLVM, with no particular meaning assigned to them.

LLVM IR apparently is not restricted to C/C++/Objc/Swift etc, it is a generally purposed IR; and LLVM itself is an infrastructure that contains many facilities to deal with compilation backends (mostly, analyses and transformations).

LLVM is not a VM in the same sense as the JVM is.

Yup.

Easy interop with C++ or Rust? I'll believe it when I see it.

It looks like it can!

http://www.scala-native.org/en/latest/user/interop.html

>Scala Native provides an interop layer that makes it easy to interact with foreign native code. This includes C and other languages that can expose APIs via C ABI (e.g. C++, D, Rust etc.)

> languages that can expose APIs via C ABI

That's what I thought.. another C-based FFI. Better than nothing, I suppose.

From that page, it looks like Scala-C interop is decent, but that's a far cry from C++/Rust interop. For C++ at least, you more or less need to write a pure-C wrapper API to call from Scala, since it doesn't handle C++ types.

You would need the same for Rust as well.

Rust's FFI is the same as C.

I'm not sure what exactly you mean by that, but what I was trying to say is that you can't expose Rust directly, you need to expose a C ABI. Which is totally doable, but is not just "drop in Rust code and it works."

Interesting, I guess I understood that wrong. Looks like no "easy" interop, but it's there if you really need it and don't mind the extra work.

I've been playing with this and trying to convert a ~20 line helper script that I use at work (and would really like to benefit from no JVM warmup time), and I've already run into missing core library functions like parallel collections and regexes.

This thing will be really great when it's ready, but it's not even close yet.

Nim has pretty decent interop with C++. In general, though, you are right that C is much much easier to interop with

Reply on news.ycombinator.com