• “=” 不返回任何值，避免了和==号混淆
• 提供两个范围操作符(a..<b and a...b)
• 与Java不同，支持操作符重载

### 特殊地方

(1, "zebra") < (2, "apple")   // true because 1 is less than 2
(3, "apple") < (3, "bird")    // true because 3 is equal to 3, and "apple" is less than "bird"
(4, "dog") == (4, "dog")      // true because 4 is equal to 4, and "dog" is equal to "dog"