一个带有操作集合方法接口的简单接口。

示例

use set;
use set::Set;

// A set that contains ASCII
let ascii = set::predicate(|c| c as u32 <= 0x7F);
assert!(ascii.contains('a'));
assert!(!ascii.contains('❤'));

let s = set::predicate(|c: char| c.is_uppercase());
assert!(s.contains('B'));

// A char is a quine atom. That is, it is a set that contains only itself.
assert!('t'.contains('t'));

// Functions and closures that match the signature of contains are themselves sets.
assert!(char::is_lowercase.contains('b'));