stage0 VS bug

Somewhat tangential, but I'm curious how big the bootstrap seed for Nix is. That is, if you wanted to build the entire world, what's a minimum set of binaries you'd need?

Guix has put quite a bit of work into this, AFAIU, and it's getting close to being bootstrappable all the way from stage0 [0]. Curious if some group is also working on similar things for Nix.

[0]:https://github.com/oriansj/stage0

https://www.bootstrappable.org/ has some good info. Reading the source of https://github.com/oriansj/stage0 is also very enlightening. It's set its goal to be understandable by 70% of programmers.

Even if they aren't, people absolutely should be able to bootstrap new platforms from scratch. It's important to have confidence in our tools, in our ability to rebuild from scratch, and to be safe against the "trusting trust" attack among other things.

Lately I've been catching up on the state of the art in bootstrapping. Check out the live-bootstrap project. stage0 starts with a seed "compiler" of a couple hundred bytes that basically turns hex codes into bytes while stripping comments. A series of such text files per architecture work their way up to a full macro assembler, which is then used to write a mostly architecture-independent minimal C compiler, which then builds a larger compiler written in this subset of C. This then bootstraps a Scheme in which a full C compiler (mescc) is written, which then builds TinyCC, which then builds GCC 4, which works its way up to modern GCC for C++... It's a fascinating read:

https://github.com/oriansj/stage0

https://github.com/fosslinux/live-bootstrap/blob/master/part...

Even if no one is "using" this it should still be a primary motivator for keeping C simple.

One countermeasure not mentioned here is bootstrapping a compiler with a program small enough to be manually verified. The stage0 project is under 1KB (small enough that the binary can be, and has been, manually checked against the hand written assembly), and GNU Guix (a system for reproducible, isolated builds) is currently working on moving it's bootstrap speed to stage0. That means that, fairly soon, there will be a large set of software that doesn't have a connection to an original C compiler.

Thank you for sharing!

It looks like the Scala project found allowing protected[this] fields as an escape hatch for variance to be unsound:

https://github.com/scala/bug/issues/7093

Going to have to chew on that and what it means for the same feature in Sorbet…

Thanks again for bringing this up!

I have a new windows 10 and downloaded the Coursier installer from scala-lang.org, the https://docs.scala-lang.org/getting-started/index.html says that you should have either java8 or java11 installed but most tutorials online and posts says to install latest version of java, which java jdk version should I install or does Coursier install it for me or do I choose the latest jdk (java-jdk-19)?

Scala

All of those dependencies are Java dependencies, not Scala libraries, except for one, and it's a known problem that is to some extent solved already and should be fully solved very soon. https://github.com/scala/bug/issues/12632

I had met the core developers, we had discussing a lot about which technology would better address our demand and, after many considerations, we had chosen Scala.

i like scala. it combines object-oriented and functional programming into one high-level language, which makes it fun to learn. i don't know if it is popular in the robotics industry, but it runs on the jvm and can be combined with java, so there is that. i recommend the book "programming scala".

See https://github.com/scala/bug/issues/12491 for info and workarounds. A fix will land in Scala 2.13.8.