Function is_xid 

pub fn is_xid(s: &str) -> bool

Returns true if s is a well-formed Unicode identifier under the default UAX #31 profile: it is non-empty, its first scalar is is_xid_start, and every remaining scalar is is_xid_continue.

This is a convenience over iterating the scalars by hand. It applies no language-specific extensions — notably it rejects a leading underscore, so callers whose grammar allows _name should test that case themselves.

Examples

use unicode_lang::is_xid;

assert!(is_xid("total"));
assert!(is_xid("Δpressure"));
assert!(is_xid("café"));

assert!(!is_xid(""));         // empty is not an identifier
assert!(!is_xid("1st"));      // cannot start with a digit
assert!(!is_xid("a b"));      // no interior whitespace
assert!(!is_xid("_name"));    // underscore is not XID; opt in separately