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The SplEnum class

(No version information available, might only be in SVN)

简介

SplEnum gives the ability to emulate and create enumeration objects natively in PHP.

类摘要

SplEnum extends SplType {
/* Constants */
const NULL __default = null ;
/* 方法 */
public array getConstList ([ bool $include_default = false ] )
/* 继承的方法 */
SplType::__construct ([ mixed $initial_value [, bool $strict ]] )
}

预定义常量

SplEnum::__default

范例

Example #1 SplEnum usage example

<?php
class Month extends SplEnum {
    const __default = self::January;
    
    const January = 1;
    const February = 2;
    const March = 3;
    const April = 4;
    const May = 5;
    const June = 6;
    const July = 7;
    const August = 8;
    const September = 9;
    const October = 10;
    const November = 11;
    const December = 12;
}

echo new Month(Month::June) . PHP_EOL;

try {
    new Month(13);
} catch (UnexpectedValueException $uve) {
    echo $uve->getMessage() . PHP_EOL;
}
?>

以上例程会输出：

6
Value not a const in enum Month

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PHP手册 - N: The SplEnum class

用户评论:

No Such Alias (30-Jul-2010 05:11)

Here's a clearer example usage in case anyone else finds the
current documentation confusing (as I did).

<?php
class Fruit extends SplEnum
{
  // If no value is given during object construction this value is used
  const __default = 1;
  // Our enum values
  const APPLE     = 1;
  const ORANGE    = 2;
}

$myApple   = new Fruit();
$myOrange  = new Fruit(Fruit::ORANGE);
$fail      = 1;

function eat(Fruit $aFruit)
{
  if (Fruit::APPLE == $aFruit) {
    echo "Eating an apple.\n";
  } elseif (Fruit::ORANGE == $aFruit) {
    echo "Eating an orange.\n";
  }
}

eat($myApple);  // Eating an apple.
eat($myOrange); // Eating an orange.

eat($fail); // PHP Catchable fatal error:  Argument 1 passed to eat() must be an instance of Fruit, integer given

?>