History

Vincent Ambo 67addf3b3d feat(tvix/eval): add error variant for threading through errors This variant is required for external builtins (which in our case includes `derivation`) to thread through reasonable error messages. This has some potential for improvement, but it's an improvement over the status quo of panicking in the external builtins when no appropriate error is available. Change-Id: I7e4bdb0a156c7717092dde30aa4785192182dc66 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7841 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI		2023-01-16 13:43:14 +00:00
..
benches	fix(tvix/eval): fix current clippy warnings	2022-12-25 18:25:06 +00:00
builtin-macros	fix(tvix/eval): VM & Builtin* types have to be public	2023-01-06 12:15:23 +00:00
docs	docs(tvix): add build-references / string-context document	2023-01-12 11:01:40 +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): add error variant for threading through errors	2023-01-16 13:43:14 +00:00
tests	feat(tvix/eval): use `EvalIO::import_path` when coercing paths	2022-12-21 22:59:18 +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	feat(tvix/eval): implement builtins.toXML	2023-01-16 13:43:14 +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.