Question

我早就对Im的问题做了简短的演示。这确实是我如何执行,但似乎会产生同样的结果。

<?php

class mainclass {

    var $vardata = array();

    function &__get ($var) {
        if ($this->vardata[$var]) return $this->vardata[$var];
        if ($var ==  foo ) return $this->_loadFoo();
        return NULL;
    }

    function __set ($var, $val) {
        $this->vardata[$var] = $val;
    }

    function __unset($var) {
        unset($this->vardata[$var]);
    }

}

class extender extends mainclass {

    function __construct() {

        var_dump($this->foo);
        $this->_loadFoo();
        echo  <br> ;
        var_dump($this->foo);

    }

    function _loadFoo () {

        unset($this->foo);
        $this->foo = array();

        $this->foo[] =  apples ;
        $this->foo[] =  oranges ;
        $this->foo[] =  pears ;

        return $this->foo;

    }

}


$test = new extender;

?>

上述法典的产出是:

array(3) { [0]=>  string(6) "apples" [1]=>  string(7) "oranges" [2]=>  string(5) "pears" }
array(5) { [0]=> string(6) "apples" [1]=> string(7) "oranges" [2]=> string(5) "pears" [3]=> string(7) "oranges" [4]=> string(5) "pears" }

如我所期望的那样:

array(3) { [0]=>  string(6) "apples" [1]=>  string(7) "oranges" [2]=>  string(5) "pears" }
array(3) { [0]=>  string(6) "apples" [1]=>  string(7) "oranges" [2]=>  string(5) "pears" }

......植被、__和__功能都在正确的地方被召唤,因此,我预计第二个功能是,直接要求该功能只是 un开 $本和gt,并用同样的数据再次填充。计算这一变数时,会得出同样的产出。相反,它最终完成上述工作......用三条直截了两条,并保持原先三套护法。

也许只是 mistake误或误解超负荷职能——要么如此,现在我就坐在这里太久了,因此,我们非常赞赏任何帮助!

Answer 1

你们的法典有许多错误:

if ($this->vardata[$var]) is not the way to check is a variable exists; isset or (if null s are allowed, array_key_exists) is.
The mainclass called a function it doesn t have. You should have declared it abstract (it would still work otherwise, but you d be exposing yourself to bugs if you instantiated the mainclass).
You didn t make your mind if you wanted _loadFoo to set a missing array element (work with collateral effects) or return the default value for the foo property. Since you re returning by reference in __get, I suppose you want to have an actual variable and not just a return value, so I went for the first route. You had _loadFoo doing both things – set the missing array index and returning the value; to complicate things you did not set the array index directly, you relied on overloads.

更正本:

<?php

abstract class mainclass {

    var $vardata = array();

    function &__get ($var) {
        if (isset($this->vardata[$var])) return $this->vardata[$var];
        if ($var ==  foo ) {
            $this->_loadFoo(); /* called for collaterals */
            return $this->foo;
        }
        return NULL;
    }

    abstract function _loadFoo();

    function __set ($var, $val) {
        $this->vardata[$var] = $val;
    }

    function __unset($var) {
        unset($this->vardata[$var]);
    }

}

class extender extends mainclass {

    function __construct() {

        var_dump($this->foo);
        $this->_loadFoo();
        echo  <br> ;
        var_dump($this->foo);

    }

    function _loadFoo () {

        unset($this->foo);
        $this->foo = array();

        $this->foo[] =  apples ;
        $this->foo[] =  oranges ;
        $this->foo[] =  pears ;

    }

}

$test = new extender;

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