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我正在寻找 SELF 和 STATIC 之间的中间地带，没有后期静态绑定的意外行为。

以下是我的代码，带有练习结果和预期结果：

<?php

class A {
public function get_self() {
    return new self();
}

public function get_static() {
    return new static();
}
}

class B extends A {}

class C {
public function static_get_a_self() {
    return A::get_self();
}

public function static_get_a_static() {
    return A::get_static();
}

public function var_get_a_self() {
    $a = new A();
    return $a->get_self();
}

public function var_get_a_static() {
    $a = new A();
    return $a->get_static();
}


public function static_get_b_self() {
    return B::get_self();
}

public function static_get_b_static() {
    return B::get_static();
}

public function var_get_b_self() {
    $b = new B();
    return $b->get_self();
}

public function var_get_b_static() {
    $b = new B();
    return $b->get_static();
}
}

$a = new A();
$b = new B();
$c = new C();

echo "Static calls: \n";
echo "B::get_self() ============= " . get_class(B::get_self()) .   " | expected A \n";
echo "B::get_static() =========== " . get_class(B::get_static()) . " | expected B \n";
echo "A::get_static() =========== " . get_class(A::get_static()) . " | expected A \n";
echo "\n";

echo "Object Calls on A: \n";
echo '$a->get_self() ============ ' . get_class($a->get_self()) .   " | expected A \n";
echo '$a->get_static() ========== ' . get_class($a->get_static()) . " | expected A \n";
echo "\n";

echo "Object Calls on B: \n";
echo '$b->get_self() ============ ' . get_class($b->get_self()) .   " | expected A \n";
echo '$b->get_static() ========== ' . get_class($b->get_static()) . " | expected B \n";
echo "\n";

echo "C Object Calls on A: \n";
echo "Internally against A::{call}\n";
echo '$c->static_get_a_self() === ' . get_class($c->static_get_a_self()) .   " | expected A \n";
echo '$c->static_get_a_static() = ' . get_class($c->static_get_a_static()) . " | expected A < Whoa! \n";
echo "Internally against \$a = new A();\n";
echo '$c->var_get_a_self() ====== ' . get_class($c->var_get_a_self()) .      " | expected A \n";
echo '$c->var_get_a_static() ==== ' . get_class($c->var_get_a_static()) .    " | expected A \n";
echo "\n";

echo "C Object Calls on B: \n";
echo "Internally against B::{call}\n";
echo '$c->static_get_b_self() === ' . get_class($c->static_get_b_self()) .   " | expected A \n";
echo '$c->static_get_b_static() = ' . get_class($c->static_get_b_static()) . " | expected B < Whoa! \n";
echo "Internally against \$b = new B();\n";
echo '$c->var_get_b_self() ====== ' . get_class($c->var_get_b_self()) .      " | expected A \n";
echo '$c->var_get_b_static() ==== ' . get_class($c->var_get_b_static()) .    " | expected B \n";
?>

结果：

Static calls: 
B::get_self() ============= A | expected A 
B::get_static() =========== B | expected B 
A::get_static() =========== A | expected A 

Object Calls on A: 
$a->get_self() ============ A | expected A 
$a->get_static() ========== A | expected A 

Object Calls on B: 
$b->get_self() ============ A | expected A 
$b->get_static() ========== B | expected B 

C Object Calls on A: 
Internally against A::{call}
$c->static_get_a_self() === A | expected A 
$c->static_get_a_static() = C | expected A < Whoa! 
Internally against $a = new A();
$c->var_get_a_self() ====== A | expected A 
$c->var_get_a_static() ==== A | expected A 

C Object Calls on B: 
Internally against B::{call}
$c->static_get_b_self() === A | expected A 
$c->static_get_b_static() = C | expected B < Whoa! 
Internally against $b = new B();
$c->var_get_b_self() ====== A | expected A 
$c->var_get_b_static() ==== B | expected B

这是有道理的，在后期静态绑定中，保留的“静态”变量指的是最后一个类范围。我正在寻找的是一个保留变量，它指的是变量出现的顶级类。

IE：如果我用一个名为 Member 的类扩展 RecordObject 类，我需要一个可以在 RecordObject 中定义的函数，它将实例化一个新的 Member（或 Page，或 Comment），而不必在每个类定义中覆盖这个函数。这可能吗？

我遇到的问题是，比如说，我在 Member 中，我调用 Page::get($id)，它在内部创建了一个新对象并做了一些魔术。不幸的是，如果我使用静态，那个新对象是一个成员......没有骰子。

4

1 回答 1

0

你为什么忽略严格的错误？

只需将static关键字添加到静态方法。

class A {
static public function get_self() {
    return new self();
}

static public function get_static() {
    return new static();
}
}

一切都应该按预期进行。

http://3v4l.org/RWRE9#v530

于 2013-11-13T05:14:40.987 回答