(PECL spl_types >= 0.1.0)
SplEnum gives the ability to emulate and create enumeration objects natively in PHP.
SplEnum::__default
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
No Such Alias (2010-07-30 09:11:37)
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
?>