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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    User Contributed Notes 1 note

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    8
    Hayley Watson
    6 months 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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