History

Vincent Ambo 972c867b36 feat(tvix/eval): add error contexts to annotate error kinds This makes it possible for users to add additional context to an error, which will then be rendered as an additional secondary span in the formatted error output. We should strive to do this basically anywhere errors are raised that can occur multiple times, especially during type casts. This was triggered by me debugging a type cast error attached to a fairly large-ish span (a builtin invocation). Change-Id: I51be41fabee00cf04de973935daf34fe6424e76f Reviewed-on: https://cl.tvl.fyi/c/depot/+/7849 Tested-by: BuildkiteCI Reviewed-by: flokli <flokli@flokli.de>		2023-01-20 15:39:51 +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 contexts to annotate error kinds	2023-01-20 15:39:51 +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	refactor(tvix/value): use proptest strategies from imbl crate	2023-01-17 10:20:38 +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.