da1e3e9ac5
This finishes up the implementation of nested keys after the key insight that the nesting level does not need to be tracked, and instead the attribute iterator can simply be retained inside the structures as is (in an advanced state). With this implementation, when encountering a nested key, the Tvix compiler will first analyse whether there is already a matching binding that can be merged (i.e. a binding that is a literal attribute set), and perform the merge, or otherwise create a new recursive set of bindings in which the entry is inserted with the path iterator advanced beyond the first name component. With this, all the logic simply applies recursively until there are no more nested bindings (i.e. until all iterators are "empty"). Note that this has one (potentially insignificant) deviation from Nix currently: If a non-mergable value is supplied (e.g. `a.b = 1; a = 2;`), Tvix will emit a *runtime* error (whereas it is *parse* time in Nix) as the branch which could statically analyse this is currently unreachable. There's a TODO for this, so we can fix it up later. Change-Id: I53df70e09614ff4281a70b80eac7da3beca12da9 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6806 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI |
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| .. | ||
| benches | ||
| docs | ||
| proptest-regressions/value | ||
| src | ||
| tests | ||
| .envrc | ||
| .gitignore | ||
| .skip-subtree | ||
| Cargo.lock | ||
| Cargo.toml | ||
| default.nix | ||
| README.md | ||
| shell.nix | ||
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.