cfg() expression parserCfg is an AST for just cfg() expressions. Target allows target triples or cfg(), so it's suitable for parsing targets Cargo allows in target.🈁️.dependencies.
```rust use parse_cfg::*; fn main() -> Result<(), ParseError> {
let cfg: Cfg = r#"cfg(any(unix, feature = "extra"))"#.parse()?; assert_eq!(Cfg::Any(vec![ Cfg::Is("unix".into()), Cfg::Equal("feature".into(), "extra".into()), ]), cfg);
let isset = cfg.eval(|key, comparison| if key == "feature" && comparison == "extra" { Some(comparison) } else { None }); assert!(isset);
let target = "powerpc64le-unknown-linux-gnu".parse()?; assert_eq!(Target::Triple { arch: "powerpc64le".into(), vendor: "unknown".into(), os: "linux".into(), env: Some("gnu".into()), }, target);
/// Cfg and Target types take an optional generic argument for the string type,
/// so you can parse slices without allocating Strings, or parse into Cow<str>.
let target = Target::<&str>::parsegeneric("powerpc64le-unknown-linux-gnu")?;
asserteq!(Target::Triple {
arch: "powerpc64le",
vendor: "unknown",
os: "linux",
env: Some("gnu"),
}, target);
Ok(()) } ```
It's safe to parse untrusted input. The depth of expressions is limited to 255 levels.
Target triples used by Rust don't follow its documented syntax, so sometimes os/vendor/env will be shifted.