History

Vincent Ambo 25fc6b7c25 feat(tvix/eval): introduce initial EvalIO trait This trait is going to be used to abstract filesystem interactions in Tvix. For now, it only contains a `read_to_string` method that closely mirrors `std::fs::read_to_string`. As a first step, to see how this works in practice, we will thread through only this function to the various relevant parts. Two implementations are provided in tvix-eval itself: A dummy implementation (which just returns ErrorKind::NotImplemented for all operations), and a std implementation which delegates to `std` functions. Change-Id: Ied3e3bf4bd0e874dd84e166190e3873a0f923ddb Reviewed-on: https://cl.tvl.fyi/c/depot/+/7565 Reviewed-by: grfn <grfn@gws.fyi> Tested-by: BuildkiteCI		2022-12-21 22:37:11 +00:00
..
benches	chore(tvix): upgrade to clap 4.0	2022-12-21 13:23:38 +00:00
builtin-macros	refactor(tvix): share a Cargo.lock file between Rust projects	2022-12-15 17:26:45 +00:00
docs	docs(tvix/eval): document abandoned thread-local vm	2022-11-08 08:41:04 +00:00
proptest-regressions/value	test(tvix/eval): Add tests for the Eq laws of Value	2022-09-18 17:57:09 +00:00
src	feat(tvix/eval): introduce initial EvalIO trait	2022-12-21 22:37:11 +00:00
tests	refactor(tvix/eval): use new public API in test code	2022-12-21 13:09:28 +00:00
.skip-subtree	feat(tvix/tests): check in Nix' language test suite	2022-08-24 21:25:41 +00:00
build.rs	feat(tvix/eval): implement builtins.currentSystem	2022-10-24 12:20:01 +00:00
Cargo.toml	fix(tvix/eval): use test-generator fork that supports workspaces	2022-12-21 13:23:38 +00:00
default.nix	refactor(tvix): build Rust projects using crate2nix	2022-12-15 17:26:45 +00:00
README.md	docs(tvix/eval): explain where to find the site-specific `mg` tool	2022-10-13 18:41:02 +00:00

README.md

Tvix Evaluator

This project implements an interpreter for the Nix programming language. You can experiment with an online version of the evaluator: tvixbolt.

The interpreter aims to be compatible with nixpkgs, on the foundation of Nix 2.3.

Important note: The evaluator is not yet feature-complete, and while the core mechanisms (compiler, runtime, ...) have stabilised somewhat, a lot of components are still changing rapidly.

Please contact TVL with any questions you might have.

Building the evaluator

If you are in a full checkout of the TVL depot, you can simply run mg build in this directory (or mg build //tvix/eval from anywhere in the repo). The mg command is found in /tools/magrathea.

Important note: We only use and test Nix builds of our software against Nix 2.3. There are a variety of bugs and subtle problems in newer Nix versions which we do not have the bandwidth to address, builds in newer Nix versions may or may not work.

The evaluator can also be built with standard Rust tooling (i.e. cargo build).

If you would like to clone only the evaluator and build it directly with Rust tooling, you can do:

git clone https://code.tvl.fyi/depot.git:/tvix/eval.git tvix-eval

cd tvix-eval && cargo build

Nix test suite

C++ Nix implements a language test suite in the form of Nix source code files, and their expected output. The coverage of this test suite is not complete, but we intend to be compatible with it.

We have ported the test suite to Tvix, but do not run it by default as we are not yet compatible with it.

You can run the test suite by enabling the nix_tests feature in Cargo:

cargo test --features nix_tests

rnix-parser

Tvix is written in memory of jD91mZM2, the author of rnix-parser who sadly passed away.

Tvix makes heavy use of rnix-parser in its bytecode compiler. The parser is now maintained by Nix community members.