枚举常量

虽然 enum 可以包括 public、private、protected 的常量， 但由于它不支持继承，因此在实践中 private 和 protected 效果是相同的。

枚举常量可以引用枚举条目：

<?php

enum Size
{
case Small;
case Medium;
case Large;

public const Huge = self::Large;
}
?>

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Hayley Watson
1 year ago
Just to clarify, enum constants *can* contain cases, but they don't *have* to; other constant values are legitimate - including cases of other Enumerations.

<?php
enum Suit
{
case Hearts;
case Clubs;
case Spades;
case Diamonds;

public const Card = Size::Large; // A case from a different enum
}

enum Size
{
case Small;
case Medium;
case Large;

public const Scale = 297/210; // A float
}

echo Suit::Diamonds::Card::Scale; // Getting the constant Scale from the constant Card in a Suit.
?>
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备份地址：http://www.lvesu.com/blog/php/language.enumerations.constants.php