在下面的PHP代码中，一行代码被注释掉（请参阅注释），并替换为下一行代码，目的是在不指定类名的情况下实现相同的效果。然而，我试图在代码中消除的显式类名对函数是隐藏的。如何在不象原始代码中那样明确地写下类名的情况下修复此问题？
class EmbeddedTriplets {
private $count;
private $values;
function __construct($value = 0, $count = 1) {
$this->count = $count;
$this->values = array($value, $value, $value);
}
public function getEmbeddedOutput() {
if ($this->count > 0) {
$output = $this->values;
$func = function($value) {
//return new EmbeddedTriplets($value);
// HERE INSTEAD OF THE LINE ABOVE I WOULD LIKE TO WRITE ACHIEVE THE SAME THING
// BUT WITHOUT SPECIFYING THE CLASS NAME (SO THAT IF THE CLASS NAME CHANGES THEN
// I WILL ONLY NEED TO CHANGE IT IN ONE PLACE IN THE CODE, i.e. next to the class keyword).
return new self($value);
};
for ($i = 0; $i < $this->count - 1; $i++) {
$output = array_map($func, $output);
}
return $output;
}
return null;
}
}
$et = new EmbeddedTriplets(10, 3);
print_r($et->getEmbeddedOutput());
输出：
<br />
<b>Fatal error</b>: Cannot access self:: when no class scope is active on line <b>25</b><br />
预期输出：
Array
(
[0] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
[1] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
[2] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
)
)
[1] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
[1] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
[2] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
)
)
[2] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
[1] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
[2] => EmbeddedTriplets Object
(
[count:EmbeddedTriplets:private] => 1
[values:EmbeddedTriplets:private] => Array
(
[0] => 10
[1] => 10
[2] => 10
)
)
)
)
)
使用__CLASS__常量：
$class = __CLASS__;
return new $class($value);
从PHP 5.5.0开始，您可以使用class:
$class = self::class;
据我所知，仍然没有一条班轮。
这不是一个更好的解决方案（它实际上使用了更多的代码行），但它展示了如何将这些函数编码为使用类实例：
class EmbeddedTriplets {
private $count;
private $values;
private $class;
function __construct($value = 0, $count = 1) {
$this->count = $count;
$this->values = array($value, $value, $value);
$this->class = __CLASS__;
}
public function getEmbeddedOutput() {
if ($this->count > 0) {
$output = $this->values;
$class = $this->class;
$func = function($value) use ($class) {
return new $class($value);
};
for ($i = 0; $i < $this->count - 1; $i++) {
$output = array_map($func, $output);
}
return $output;
}
return null;
}
}
$et = new EmbeddedTriplets(10, 3);
print_r($et->getEmbeddedOutput());