我知道PHP还没有本地枚举。但是我已经习惯了来自Java世界的它们。我喜欢使用枚举来提供ide的自动补全功能能够理解的预定义值。
常量可以解决这个问题,但是存在名称空间冲突问题,而且(实际上是因为)它们是全局的。数组没有名称空间的问题,但是它们太模糊了,它们可以在运行时被覆盖,而且ide很少知道如何在没有额外的静态分析注释或属性的情况下自动填充它们的键。
你有什么常用的解决方案/变通办法吗?有人记得PHP的人对枚举有什么想法或决定吗?
我知道PHP还没有本地枚举。但是我已经习惯了来自Java世界的它们。我喜欢使用枚举来提供ide的自动补全功能能够理解的预定义值。
常量可以解决这个问题,但是存在名称空间冲突问题,而且(实际上是因为)它们是全局的。数组没有名称空间的问题,但是它们太模糊了,它们可以在运行时被覆盖,而且ide很少知道如何在没有额外的静态分析注释或属性的情况下自动填充它们的键。
你有什么常用的解决方案/变通办法吗?有人记得PHP的人对枚举有什么想法或决定吗?
当前回答
我只是创建了一个库,希望它能完成这项工作。它可以在任何PHP项目中独立使用,并且有一些Laravel的好东西可以让生活变得更简单。我在生产项目中使用它们。
https://github.com/Kwaadpepper/enum
如果你喜欢或不喜欢,不要犹豫提供反馈。 它可以被打印出来,并序列化为JSON。它的定义很简单。
用法非常简单:
$enum = BasicEnum::someValue();
echo $enum->equals(BasicEnum::someValue()) ? 'true' : 'false'; // true
echo $enum->value; // 'someValue' or the value you have defined
echo $enum->label; // 'someValue' or the label you have defined
echo $enum; // 'someValue' or the value you have defined
echo json_encode($enum); // {"label": "someValue", "value: "someValue" }
枚举定义非常简单(值和标签方法是可选的)
/**
* @method static self post()
* @method static self about()
* @method static self contact()
*/
class PostType extends BaseEnum
{
protected static function values(): array
{
return [
'post' => 0,
'about' => 1,
'contact' => 2
];
}
protected static function labels(): array
{
return [
'post' => 'Regular posts',
'about' => 'The about page',
'contact' => 'The contact page'
];
}
}
其他回答
昨天我在博客上写了这门课。我认为在php脚本中使用它可能很容易:
final class EnumException extends Exception{}
abstract class Enum
{
/**
* @var array ReflectionClass
*/
protected static $reflectorInstances = array();
/**
* Массив конфигурированного объекта-константы enum
* @var array
*/
protected static $enumInstances = array();
/**
* Массив соответствий значение->ключ используется для проверки -
* если ли константа с таким значением
* @var array
*/
protected static $foundNameValueLink = array();
protected $constName;
protected $constValue;
/**
* Реализует паттерн "Одиночка"
* Возвращает объект константы, но но как объект его использовать не стоит,
* т.к. для него реализован "волшебный метод" __toString()
* Это должно использоваться только для типизачии его как параметра
* @paradm Node
*/
final public static function get($value)
{
// Это остается здесь для увеличения производительности (по замерам ~10%)
$name = self::getName($value);
if ($name === false)
throw new EnumException("Неизвестая константа");
$className = get_called_class();
if (!isset(self::$enumInstances[$className][$name]))
{
$value = constant($className.'::'.$name);
self::$enumInstances[$className][$name] = new $className($name, $value);
}
return self::$enumInstances[$className][$name];
}
/**
* Возвращает массив констант пар ключ-значение всего перечисления
* @return array
*/
final public static function toArray()
{
$classConstantsArray = self::getReflectorInstance()->getConstants();
foreach ($classConstantsArray as $k => $v)
$classConstantsArray[$k] = (string)$v;
return $classConstantsArray;
}
/**
* Для последующего использования в toArray для получения массива констант ключ->значение
* @return ReflectionClass
*/
final private static function getReflectorInstance()
{
$className = get_called_class();
if (!isset(self::$reflectorInstances[$className]))
{
self::$reflectorInstances[$className] = new ReflectionClass($className);
}
return self::$reflectorInstances[$className];
}
/**
* Получает имя константы по её значению
* @param string $value
*/
final public static function getName($value)
{
$className = (string)get_called_class();
$value = (string)$value;
if (!isset(self::$foundNameValueLink[$className][$value]))
{
$constantName = array_search($value, self::toArray(), true);
self::$foundNameValueLink[$className][$value] = $constantName;
}
return self::$foundNameValueLink[$className][$value];
}
/**
* Используется ли такое имя константы в перечислении
* @param string $name
*/
final public static function isExistName($name)
{
$constArray = self::toArray();
return isset($constArray[$name]);
}
/**
* Используется ли такое значение константы в перечислении
* @param string $value
*/
final public static function isExistValue($value)
{
return self::getName($value) === false ? false : true;
}
final private function __clone(){}
final private function __construct($name, $value)
{
$this->constName = $name;
$this->constValue = $value;
}
final public function __toString()
{
return (string)$this->constValue;
}
}
用法:
class enumWorkType extends Enum
{
const FULL = 0;
const SHORT = 1;
}
上面的答案太棒了。但是,如果以两种不同的方式进行扩展,那么无论先进行哪种扩展,都会导致对函数的调用,从而创建缓存。这个缓存将被所有后续调用使用,无论调用是由哪个扩展发起的…
要解决这个问题,将变量和第一个函数替换为:
private static $constCacheArray = null;
private static function getConstants() {
if (self::$constCacheArray === null) self::$constCacheArray = array();
$calledClass = get_called_class();
if (!array_key_exists($calledClass, self::$constCacheArray)) {
$reflect = new \ReflectionClass($calledClass);
self::$constCacheArray[$calledClass] = $reflect->getConstants();
}
return self::$constCacheArray[$calledClass];
}
对于简单的枚举,我使用如下结构。通常,您可以将它们用于switch语句。
<?php
define("OPTION_1", "1");
define("OPTION_2", OPTION_1 + 1);
define("OPTION_3", OPTION_2 + 1);
// Some function...
switch($Val){
case OPTION_1:{ Perform_1();}break;
case OPTION_2:{ Perform_2();}break;
...
}
?>
它不像c++中的本地枚举那样方便,但如果你以后想在两者之间添加一个选项,它似乎可以工作,并且需要更少的维护。
我知道这是一个非常非常非常古老的话题,但我对此有一个想法,想知道人们是怎么想的。
注:我在玩这个,并意识到如果我只是修改__call()函数,你可以更接近实际的枚举。__call()函数处理所有未知函数调用。假设你想创建三个枚举RED_LIGHT, YELLOW_LIGHT和GREEN_LIGHT。你现在只需做以下事情就可以做到:
$c->RED_LIGHT();
$c->YELLOW_LIGHT();
$c->GREEN_LIGHT();
一旦定义了,你所要做的就是再次调用它们来获取值:
echo $c->RED_LIGHT();
echo $c->YELLOW_LIGHT();
echo $c->GREEN_LIGHT();
得到0 1 2。玩得开心!这个现在也在GitHub上。
更新:我已经这样做了,所以__get()和__set()函数现在都被使用。这允许您不必调用函数,除非您愿意。相反,现在你可以说:
$c->RED_LIGHT;
$c->YELLOW_LIGHT;
$c->GREEN_LIGHT;
对于价值的创造和获取。因为变量最初还没有定义,所以调用__get()函数(因为没有指定值),它会发现数组中的条目还没有创建。因此,它创建条目,将最后一个给定值赋给它+1(+1),对最后一个值变量加1,并返回TRUE。如果你设置这个值:
$c->RED_LIGHT = 85;
然后调用__set()函数,最后一个值被设置为新值+1(+1)。现在我们有了一个很好的方法来处理枚举,并且可以动态地创建它们。
<?php
################################################################################
# Class ENUMS
#
# Original code by Mark Manning.
# Copyrighted (c) 2015 by Mark Manning.
# All rights reserved.
#
# This set of code is hereby placed into the free software universe
# via the GNU greater license thus placing it under the Copyleft
# rules and regulations with the following modifications:
#
# 1. You may use this work in any other work. Commercial or otherwise.
# 2. You may make as much money as you can with it.
# 3. You owe me nothing except to give me a small blurb somewhere in
# your program or maybe have pity on me and donate a dollar to
# sim_sales@paypal.com. :-)
#
# Blurb:
#
# PHP Class Enums by Mark Manning (markem-AT-sim1-DOT-us).
# Used with permission.
#
# Notes:
#
# VIM formatting. Set tabs to four(4) spaces.
#
################################################################################
class enums
{
private $enums;
private $clear_flag;
private $last_value;
################################################################################
# __construct(). Construction function. Optionally pass in your enums.
################################################################################
function __construct()
{
$this->enums = array();
$this->clear_flag = false;
$this->last_value = 0;
if( func_num_args() > 0 ){
return $this->put( func_get_args() );
}
return true;
}
################################################################################
# put(). Insert one or more enums.
################################################################################
function put()
{
$args = func_get_args();
#
# Did they send us an array of enums?
# Ex: $c->put( array( "a"=>0, "b"=>1,...) );
# OR $c->put( array( "a", "b", "c",... ) );
#
if( is_array($args[0]) ){
#
# Add them all in
#
foreach( $args[0] as $k=>$v ){
#
# Don't let them change it once it is set.
# Remove the IF statement if you want to be able to modify the enums.
#
if( !isset($this->enums[$k]) ){
#
# If they sent an array of enums like this: "a","b","c",... then we have to
# change that to be "A"=>#. Where "#" is the current count of the enums.
#
if( is_numeric($k) ){
$this->enums[$v] = $this->last_value++;
}
#
# Else - they sent "a"=>"A", "b"=>"B", "c"=>"C"...
#
else {
$this->last_value = $v + 1;
$this->enums[$k] = $v;
}
}
}
}
#
# Nope! Did they just sent us one enum?
#
else {
#
# Is this just a default declaration?
# Ex: $c->put( "a" );
#
if( count($args) < 2 ){
#
# Again - remove the IF statement if you want to be able to change the enums.
#
if( !isset($this->enums[$args[0]]) ){
$this->enums[$args[0]] = $this->last_value++;
}
#
# No - they sent us a regular enum
# Ex: $c->put( "a", "This is the first enum" );
#
else {
#
# Again - remove the IF statement if you want to be able to change the enums.
#
if( !isset($this->enums[$args[0]]) ){
$this->last_value = $args[1] + 1;
$this->enums[$args[0]] = $args[1];
}
}
}
}
return true;
}
################################################################################
# get(). Get one or more enums.
################################################################################
function get()
{
$num = func_num_args();
$args = func_get_args();
#
# Is this an array of enums request? (ie: $c->get(array("a","b","c"...)) )
#
if( is_array($args[0]) ){
$ary = array();
foreach( $args[0] as $k=>$v ){
$ary[$v] = $this->enums[$v];
}
return $ary;
}
#
# Is it just ONE enum they want? (ie: $c->get("a") )
#
else if( ($num > 0) && ($num < 2) ){
return $this->enums[$args[0]];
}
#
# Is it a list of enums they want? (ie: $c->get( "a", "b", "c"...) )
#
else if( $num > 1 ){
$ary = array();
foreach( $args as $k=>$v ){
$ary[$v] = $this->enums[$v];
}
return $ary;
}
#
# They either sent something funky or nothing at all.
#
return false;
}
################################################################################
# clear(). Clear out the enum array.
# Optional. Set the flag in the __construct function.
# After all, ENUMS are supposed to be constant.
################################################################################
function clear()
{
if( $clear_flag ){
unset( $this->enums );
$this->enums = array();
}
return true;
}
################################################################################
# __call(). In case someone tries to blow up the class.
################################################################################
function __call( $name, $arguments )
{
if( isset($this->enums[$name]) ){ return $this->enums[$name]; }
else if( !isset($this->enums[$name]) && (count($arguments) > 0) ){
$this->last_value = $arguments[0] + 1;
$this->enums[$name] = $arguments[0];
return true;
}
else if( !isset($this->enums[$name]) && (count($arguments) < 1) ){
$this->enums[$name] = $this->last_value++;
return true;
}
return false;
}
################################################################################
# __get(). Gets the value.
################################################################################
function __get($name)
{
if( isset($this->enums[$name]) ){ return $this->enums[$name]; }
else if( !isset($this->enums[$name]) ){
$this->enums[$name] = $this->last_value++;
return true;
}
return false;
}
################################################################################
# __set(). Sets the value.
################################################################################
function __set( $name, $value=null )
{
if( isset($this->enums[$name]) ){ return false; }
else if( !isset($this->enums[$name]) && !is_null($value) ){
$this->last_value = $value + 1;
$this->enums[$name] = $value;
return true;
}
else if( !isset($this->enums[$name]) && is_null($value) ){
$this->enums[$name] = $this->last_value++;
return true;
}
return false;
}
################################################################################
# __destruct(). Deconstruct the class. Remove the list of enums.
################################################################################
function __destruct()
{
unset( $this->enums );
$this->enums = null;
return true;
}
}
#
# Test code
#
# $c = new enums();
# $c->RED_LIGHT(85);
# $c->YELLOW_LIGHT = 23;
# $c->GREEN_LIGHT;
#
# echo $c->RED_LIGHT . "\n";
# echo $c->YELLOW_LIGHT . "\n";
# echo $c->GREEN_LIGHT . "\n";
?>
abstract class Enumeration
{
public static function enum()
{
$reflect = new ReflectionClass( get_called_class() );
return $reflect->getConstants();
}
}
class Test extends Enumeration
{
const A = 'a';
const B = 'b';
}
foreach (Test::enum() as $key => $value) {
echo "$key -> $value<br>";
}