virgil
nixpkgs
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virgil
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Garbage Collection for Systems Programmers
For (2) Virgil has several features that allow you to layout memory with various levels of control. I assume you meaning "array of structs", and you can do that with arrays of tuples, which will naturally be flattened and normalized based on the target (i.e. will be array-of-structs on native targets). You can define byte-exact layouts[1] (mostly for interfacing with other software and parsing binary formats), unbox ADTs, and soon you can even control the exact encoding of ADTs.
Virgil is GC'd.
[1] https://github.com/titzer/virgil/blob/master/doc/tutorial/La...
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The Return of the Frame Pointers
Virgil doesn't use frame pointers. If you don't have dynamic stack allocation, the frame of a given function has a fixed size can be found with a simple (binary-search) table lookup. Virgil's technique uses an additional page-indexed range that further restricts the lookup to be a few comparisons on average (O(log(# retpoints per page)). It combines the unwind info with stackmaps for GC. It takes very little space.
The main driver is in (https://github.com/titzer/virgil/blob/master/rt/native/Nativ... the rest of the code in the directory implements the decoding of metadata.
I think frame pointers only make sense if frames are dynamically-sized (i.e. have stack allocation of data). Otherwise it seems weird to me that a dynamic mechanism is used when a static mechanism would suffice; mostly because no one agreed on an ABI for the metadata encoding, or an unwind routine.
I believe the 1-2% measurement number. That's in the same ballpark as pervasive checks for array bounds checks. It's weird that the odd debugging and profiling task gets special pleading for a 1% cost but adding a layer of security gets the finger. Very bizarre priorities.
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Whose baseline (compiler) is it anyway?
This paper is the first time I seen mention of the Virgil programming language, from the same author:
https://github.com/titzer/virgil
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JEP 450: Compact Object Headers
JavaScript handles the "no identity hash" with WeakMap and WeakSet, which are language built-ins. For Virgil, I chose to leave out identity hashes and don't really regret it. It keeps the language simple and the separation clear. HashMap (entirely library code, not a language wormhole) takes the hash function and equality function as arguments to the constructor.
[1] https://github.com/titzer/virgil/blob/master/lib/util/Map.v3
This is partly my style too; I try to avoid using maps for things unless they are really far flung, and the things that end up serving as keys in one place usually end up serving as keys in lots of other places too.
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Retrofitting null-safety onto Java at Meta
Whoa, interesting. I didn't know Kotlin had all those constructs.
In Virgil, a method on an object (or ADT) can declare its return type as "this". Then the method implicitly returns the receiver object. That trick is very useful to allow a chain of calls such as object.foo().bar().baz(). I find it readable and easy to explain:
https://github.com/titzer/virgil/blob/master/doc/tutorial/Re...
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A Ruby program that generates itself (through a 128-language quine loop)
I hadn't written one until ~30 mins ago [1]. I cheated and looked at a Java quine (not particularly elegant, but easy to see what is going on.), but I wrote one for Virgil. Just think string substitution; a string with a hole in it and you substitute a copy of the string, quoted into the hole. Just one substitution suffices.
[1] https://github.com/titzer/virgil/blob/master/apps/Quine/Quin...
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Integer Conversions and Safe Comparisons in C++20
Virgil has a family of completely well-defined (i.e. no UB) fixed-size integer types with some hard-fought rules that I eventually got around to documenting here:
https://github.com/titzer/virgil/blob/master/doc/tutorial/Fi...
One of the key things is that values are never silently truncated (other than 2's-complement wrap-around) or values changed; only promotions. The only sane semantics for over-shifts (shifts larger than the size of the type) is to shift the bits out, like a window.
The upshot of all that is that Virgil has a pretty sane semantics for fixed-size integers, IMHO.
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Show HN: We are trying to (finally) get tail-calls into the WebAssembly standard
LLVM and other compilers that use SSA but target a stack machine can run a stackification phase. Even without reordering instructions, it seems to work well in practice.
In Virgil I implemented this for both the JVM and Wasm. Here's the algorithm used for Wasm:
https://github.com/titzer/virgil/blob/master/aeneas/src/mach...
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Hacker News top posts: Jul 2, 2022
Virgil: A fast and lightweight programming language that compiles to WASM\ (54 comments)
- Virgil: A fast and lightweight programming language that compiles to WASM
nixpkgs
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Nix: The Breaking Point
I don't think so. The article is probably intended for the Nix community, so the author doesn't need to convince HN that something is going on. If as an outsider you are interested then you need to look into it yourself, the community has no obligation to make their internal conflicts legible to the outside world.
As an outsider myself, it certainly looks like something is going on as more than 20 Nixpkg maintainers left in a week: https://github.com/NixOS/nixpkgs/issues?q=label%3A%228.has%3...
- Maintainers Leaving
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Air Force picks Anduril, General Atomics to develop unmanned fighter jets
https://github.com/NixOS/nixpkgs/commits?author=neon-sunset
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Eelco Dolstra's leadership is corrosive to the Nix project
I see two signers in the top 6 displayed on https://github.com/NixOS/nixpkgs/graphs/contributors
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3rd Edition of Programming: Principles and Practice Using C++ by Stroustrup
For a single file script, nix can make the package management quite easy: https://github.com/NixOS/nixpkgs/blob/master/doc/languages-f...
For example,
```
- NixOS/nixpkgs: There isn't a clear canonical way to refer to a specific package
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NixOS Is Not Reproducible
Yes, Nix doesn't actually ensure that the builds are deterministic. In fact it works just fine if they aren't. There are packages in nixpkgs that aren't reproducible: https://github.com/NixOS/nixpkgs/issues?q=is%3Aopen+is%3Aiss...
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The xz attack shell script
I'm not familiar with Bazel, but Nix in it's current form wouldn't have solved this attack. First of all, the standard mkDerivation function calls the same configure; make; make install process that made this attack possible. Nixpkgs regularly pulls in external resources (fetchUrl and friends) that are equally vulnerable to a poisoned release tarball. Checkout the comment on the current xz entry in nixpkgs https://github.com/NixOS/nixpkgs/blob/master/pkgs/tools/comp...
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Debian Git Monorepo
NixOS uses a monorepo and I think everyone's love it.
I love being able to easily grep through all the packages source code and there's regularly PRs that harmonizes conventions across many packages.
Nixpkgs doesn't include the packaged software source code, so it's a lot more practical than what Debian is doing.
https://github.com/NixOS/nixpkgs
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From xz to ibus: more questionable tarballs
In this specific case, nix uses fetchFromGitHub to download the source archive, which are generated by GitHub for the specified revision[1]. Arch seems to just download the tarball from the releases page[2].
[1]: https://github.com/NixOS/nixpkgs/blob/3c2fdd0a4e6396fc310a6e...
[2]: https://gitlab.archlinux.org/archlinux/packaging/packages/ib...
What are some alternatives?
vigil - Vigil, the eternal morally vigilant programming language
asdf - Extendable version manager with support for Ruby, Node.js, Elixir, Erlang & more
libratbag - A DBus daemon to configure input devices, mainly high-end and gaming mice
Home Manager using Nix - Manage a user environment using Nix [maintainer=@rycee]
rust-asn1 - A Rust ASN.1 (DER) serializer.
git-lfs - Git extension for versioning large files
kcachegrind - GUI to profilers such as Valgrind
easyeffects - Limiter, compressor, convolver, equalizer and auto volume and many other plugins for PipeWire applications
v86 - x86 PC emulator and x86-to-wasm JIT, running in the browser
spack - A flexible package manager that supports multiple versions, configurations, platforms, and compilers.
Solaar - Linux device manager for Logitech devices
waydroid - Waydroid uses a container-based approach to boot a full Android system on a regular GNU/Linux system like Ubuntu.