History

Vincent Ambo 8f2004d360 refactor(tvix/eval): add VM::call_value helper method This makes it possible to call a callable value (builtin or closure/lambda) directly, without unwrapping it first. This is needed for pretty much all higher-order functions to work correctly. This is mostly equivalent to the previous code in coerce_to_string for calling `__toString`, except it expects the argument(s) to already be placed on the stack. Note that the span for the `NotCallable` error is not currently guaranteed to make any sense, will experiment with this. Change-Id: I821224368d438a28900858b343defc1817e46a0a Reviewed-on: https://cl.tvl.fyi/c/depot/+/6717 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>		2022-09-20 23:48:57 +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	refactor(tvix/eval): add VM::call_value helper method	2022-09-20 23:48:57 +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	refactor(tvix/eval): use Clap for arg+env parsing	2022-09-18 22:08:43 +00:00
Cargo.toml	refactor(tvix/eval): use Clap for arg+env parsing	2022-09-18 22:08:43 +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.