Struct cfg_expr::expr::Expression

pub struct Expression { /* fields omitted */ }

A parsed cfg() expression that can evaluated

Methods

impl Expression

pub fn parse(original: &str) -> Result<Self, ParseError>

Given a cfg() expression (the cfg( and ) are optional), attempts to parse it into a form where it can be evaluated

assert!(cfg_expr::Expression::parse(r#"cfg(all(unix, target_arch = "x86_64"))"#).is_ok());

impl Expression

pub fn predicates(&self) -> impl Iterator<Item = Predicate>

An iterator over each predicate in the expression

pub fn eval<EP: FnMut(&Predicate) -> bool>(&self, eval_predicate: EP) -> bool

Evaluates the expression, using the provided closure to determine the value of each predicate, which are then combined into a final result depending on the functions not(), all(), or any() in the expression

use cfg_expr::{targets::*, Expression, Predicate};

let linux_musl = get_target_by_triple("x86_64-unknown-linux-musl").unwrap();

let expr = Expression::parse(r#"all(not(windows), target_env = "musl", any(target_arch = "x86", target_arch = "x86_64"))"#).unwrap();

assert!(expr.eval(|pred| {
    match pred {
        Predicate::Target(tp) => tp.matches(linux_musl),
        _ => false,
    }
}));

Trait Implementations

impl Debug for Expression

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.