History

Vincent Ambo 0f59fe6601 feat(tvix/eval): implement initial fancy formatting for errors This very closely follows the way it's done for warnings, but errors have a lot more information available in some cases which we do not surface yet. Note also that due to requiring the `CodeMap`, this is not yet called from eval.rs as the way that is threaded through needs to be refactored, so only the method for reporting these errors as strings is implemented so far. Next steps for this will be to add a generic diagnostics module that reduces some of the boilerplate for this between warnings & errors, and which will also give us a good point in the future to switch to a fancier diagnostics crate. Change-Id: If6bb209f8e7a568d866e516a90335b9b2afbf66d Reviewed-on: https://cl.tvl.fyi/c/depot/+/6534 Reviewed-by: grfn <grfn@gws.fyi> Tested-by: BuildkiteCI		2022-09-13 14:41:57 +00:00
..
benches	test(tvix/eval): Add attr merge benchmarks	2022-09-03 06:56:02 +00:00
docs	docs(tvix/eval): propose builtin "inlining" optimisation	2022-09-11 20:02:46 +00:00
src	feat(tvix/eval): implement initial fancy formatting for errors	2022-09-13 14:41:57 +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	chore(tvix/eval): add dependency on codemap-diagnostic	2022-09-13 10:54:14 +00:00
Cargo.toml	chore(tvix/eval): add dependency on codemap-diagnostic	2022-09-13 10:54:14 +00:00
default.nix	fix(tvix/eval): don't rebuild drv upon changes in cargo target dir	2022-09-04 21:02:50 +00:00
README.md	docs(tvix/eval): remove the note on the private repo	2022-09-11 19:58:44 +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.