Macro regex 

macro_rules! regex {
    ($re:literal) => { ... };
}

A convenient way to construct regex patterns from string literals.

This macro can be used to construct reusable instances of Regex with reduced boilerplate. The constructed Regex is stored in a static so the pattern is compiled approximately once, even when called multiple times.

There is no compile-time checking of patterns with regex!. Instead, invalid patterns will panic the first time the regex is used. Invalid patterns should still not be used with regex!; if compile-time checking becomes feasible in the future, it may be added within a non-semver-breaking release. In the meantime, consider enabling clippy::invalid_regex.

Examples

use regex::{Regex, regex};

assert!(regex!("[a-z]").is_match("a"));
assert!(regex!("(inconceivable!|classic blunder)").is_match("inconceivable!"));

let re: &Regex = regex!(r"(\d{3})-(\d{4})");
assert_eq!(&re.captures("867-5309").unwrap()[1], "867");

An invalid pattern will panic when it is first used:

use regex::regex;

let re = regex!("invalid -> ("); // no panic here
re.is_match("invalid -> (");     // panic!