History

Vincent Ambo 3f34af205f feat(tvix/eval): add scaffolding for merging nested attribute sets This sets up the required logic for finding and merging attribute sets into nested bindings if they exist. This is absolutely not complete yet and can, at this commit, probably cause undefined runtime behaviour if nested attributes are specified. The basic idea is that a new helper function on the `TrackedBindings` struct is called with each encountered attribute and determines whether the new entry can be merged into an existing attribute or not. Right now the only effect this has in practice is that a new error becomes available if somebody attempts to cause a merge into an inherited key. Change-Id: Id010df3605055eb1ad7fa65241055889dd21bab0 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6798 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>		2022-09-29 17:46:02 +00:00
..
benches	refactor(tvix/eval): use Clap for arg+env parsing	2022-09-18 22:08:43 +00:00
docs	docs(tvix/eval): note C++ implementation details for C++ Nix	2022-09-18 15:01:34 +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 scaffolding for merging nested attribute sets	2022-09-29 17:46:02 +00:00
tests	refactor(tvix/eval): use Clap for arg+env parsing	2022-09-18 22:08:43 +00:00
.envrc	chore(tvix/eval): add simple .envrc / shell.nix	2022-09-17 17:31:08 +00:00
.gitignore	feat(tvix/eval): check in generated project skeleton	2022-08-12 12:34:29 +00:00
.skip-subtree	feat(tvix/tests): check in Nix' language test suite	2022-08-24 21:25:41 +00:00
Cargo.lock	fix(tvix/eval): support string identifiers in inherits	2022-09-22 23:07:14 +00:00
Cargo.toml	fix(tvix/eval): support string identifiers in inherits	2022-09-22 23:07:14 +00:00
default.nix	test(tvix/eval): Add the start of a nix oracle test suite	2022-09-17 17:23:55 +00:00
README.md	docs(tvix/eval): remove the note on the private repo	2022-09-11 19:58:44 +00:00
shell.nix	chore(tvix/eval): add rustfmt to the shell	2022-09-18 23:19:54 +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).

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.