3d238c350b
Previously the construction of globals (a compiler-only concept) and builtins (a (now) user-facing API) was intermingled between multiple different modules, and kind of difficult to understand. The complexity of this had grown in large part due to the implementation of `builtins.import`, which required the notorious "knot-tying" trick using Rc::new_cyclic (see cl/7097) for constructing the set of globals. As part of the new `Evaluation` API users should have the ability to bring their own builtins, and control explicitly whether or not impure builtins are available (regardless of whether they're compiled in or not). To streamline the construction and allow the new API features to work, this commit restructures things by making these changes: 1. The `tvix_eval::builtins` module is now only responsible for exporting sets of builtins. It no longer has any knowledge of whether or not certain sets (e.g. only pure, or pure+impure) are enabled, and it has no control over which builtins are globally available (this is now handled in the compiler). 2. The compiler module is now responsible for both constructing the final attribute set of builtins from the set of builtins supplied by a user, as well as for populating its globals (that is identifiers which are available at the top-level scope). 3. The `Evaluation` API now carries a `builtins` field which is populated with the pure builtins by default, and can be extended by users. 4. The `import` feature has been moved into the compiler, as a special case. In general, builtins no longer have the ability to reference the "fix point" of the globals set. This should not change any functionality, and in fact preserves minor differences between Tvix/Nix that we already had (such as `builtins.builtins` not existing). Change-Id: Icdf5dd50eb81eb9260d89269d6e08b1e67811a2c Reviewed-on: https://cl.tvl.fyi/c/depot/+/7738 Reviewed-by: sterni <sternenseemann@systemli.org> Autosubmit: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Reviewed-by: flokli <flokli@flokli.de> |
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| benches | ||
| builtin-macros | ||
| docs | ||
| proptest-regressions/value | ||
| src | ||
| tests | ||
| .skip-subtree | ||
| build.rs | ||
| Cargo.toml | ||
| default.nix | ||
| 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.