extendr-macros

A procedural macro crate for extendr-api.

This crate implements macros such as the #[extendr] function markup and the extendr_module! macro. See extendr-api for more details.

For Developers

This crate uses trybuild for testing procedural macros. Trybuild compiles test cases in tests/cases/ and tests/extendr_impl/ and verifies that the compiler produces expected error messages for invalid code.

Running Tests

To run the trybuild tests:

cargo test --package extendr-macros --test trybuild

Updating Expected Outputs

When you intentionally change error messages or add new test cases, you need to update the expected output files (.stderr files). Use the TRYBUILD=overwrite environment variable to automatically update them:

TRYBUILD=overwrite cargo test --package extendr-macros --test trybuild

This will regenerate the .stderr files in the tests/cases/ directory to match the current compiler output.