Statement on glibc/iconv Vulnerability

    Trait

    枚举也能使用 trait，行为和 class 一样。 留意在枚举中 use trait 不允许包含属性。 只能包含方法、静态方法。 包含属性的 trait 会导致 fatal 错误。

    <?php

    interface Colorful
    {
    public function     color(): string;
    }

    trait     Rectangle
    {
    public function     shape(): string {
    return     "Rectangle";
    }
    }

    enum     Suit implements Colorful
    {
    use     Rectangle;

    case     Hearts;
    case     Diamonds;
    case     Clubs;
    case     Spades;

    public function     color(): string
    {
    return match(    $this) {
    Suit::Hearts, Suit::Diamonds => 'Red',
    Suit::Clubs, Suit::Spades => 'Black',
    };
    }
    }
    ?>

    Improve This Page

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes 1 note

    up
    1
    wervin at mail dot com
    2 months ago
    One good example of a trait, would be to give a lot of enums a method to retrieve their cases, values or both.

    <?php
    trait EnumToArray
    {
    public static function     names(): array
    {
    return     array_column(self::cases(), 'name');

    }

    public static function     values(): array
    {
    return     array_column(self::cases(), 'value');
    }

    public static function     asArray(): array
    {
    if (empty(    self::values())) {
    return     self::names();
    }

    if (empty(    self::names())) {
    return     self::values();
    }

    return     array_column(self::cases(), 'value', 'name');
    }
    }
    ?>

    Some example outputs:

    <?php
    var_export    (IpVersion::names()); // ['Ipv4', 'IPv6']
    var_export(IpVersion::values()); // []
    var_export(IpVersion::asArray()); // ['IPv4', 'IPv6']

    var_export(Language::names()); // ['en', 'es']
    var_export(Language::values()); // ['English', 'Spanish']
    var_export(Language::asArray()); // ['en' => 'English', 'es' => 'Spanish']
    ＋add a note
    To Top