Charlie Marsh
14507a1793
## Summary Brings more consistency to the repo and ensures that all crates automatically show up in `--verbose` logging.
Dependency specifiers (PEP 508) in Rust
A library for python dependency specifiers, better known as PEP 508.
Usage
use std::str::FromStr;
use pep508_rs::Requirement;
let marker = r#"requests [security,tests] >= 2.8.1, == 2.8.* ; python_version > "3.8""#;
let dependency_specification = Requirement::from_str(marker).unwrap();
assert_eq!(dependency_specification.name, "requests");
assert_eq!(dependency_specification.extras, Some(vec!["security".to_string(), "tests".to_string()]));
Markers
Markers allow you to install dependencies only in specific environments (python version, operating
system, architecture, etc.) or when a specific feature is activated. E.g. you can say
importlib-metadata ; python_version < "3.8" or itsdangerous (>=1.1.0) ; extra == 'security'.
Unfortunately, the marker grammar has some oversights (e.g.
https://github.com/pypa/packaging.python.org/pull/1181) and the design of comparisons (PEP 440
comparisons with lexicographic fallback) leads to confusing outcomes. This implementation tries to
carefully validate everything and emit warnings whenever bogus comparisons with unintended semantics
are made.