PHP: 预定义类

预定义类

本节列出标准的预定义类。各种扩展库定义了其它类，其说明在各自的参考文档中。

标准类

这些类由一些内建在 PHP 中的标准函数定义。

Directory: 由 dir() 创建。
stdClass: 使用类型转换为对象或者各种标准函数创建的通用空类。
__PHP_Incomplete_Class: 可能由 unserialize() 创建。
Exception
ErrorException
php_user_filter
Closure: 预定义的 final 类 Closure，它可以用于实现匿名函数。
Generator: 预定义的 final 类 Generator，它可以用于实现生成器。
ArithmeticError
AssertionError
DivisionByZeroError
Error
Throwable
ParseError
TypeError

特殊的类

以下这些标识符由于它们有特殊的用处，因此不可作为类名

self: 当前类。
static: 运行时的当前类。
parent: 父级类。

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用户贡献的备注 6 notes

down

spark at limao dot com dot br ¶

13 years ago

if you want a Dynamic class you can extend from, add atributes AND methods on the fly you can use this:
<?php
    class Dynamic extends stdClass{
        public function __call($key,$params){
            if(!isset($this->{$key})) throw new Exception("Call to undefined method ".get_class($this)."::".$key."()");
            $subject = $this->{$key};
            call_user_func_array($subject,$params);
        }
    }
?>

this will accept both arrays, strings and Closures:
<?php
    $dynamic->myMethod = "thatFunction";
    $dynamic->hisMethod = array($instance,"aMethod");
    $dynamic->newMethod = array(SomeClass,"staticMethod");
    $dynamic->anotherMethod = function(){
        echo "Hey there";
    };
?>

then call them away =D

down

wyattstorch42 at outlook dot com ¶

11 years ago

If you call var_export() on an instance of stdClass, it attempts to export it using ::__set_state(), which, for some reason, is not implemented in stdClass.

However, casting an associative array to an object usually produces the same effect (at least, it does in my case). So I wrote an improved_var_export() function to convert instances of stdClass to (object) array () calls. If you choose to export objects of any other class, I'd advise you to implement ::__set_state().

<?php
/**
 * An implementation of var_export() that is compatible with instances
 * of stdClass.
 * @param mixed $variable The variable you want to export
 * @param bool $return If used and set to true, improved_var_export()
 *     will return the variable representation instead of outputting it.
 * @return mixed|null Returns the variable representation when the
 *     return parameter is used and evaluates to TRUE. Otherwise, this
 *     function will return NULL.
 */
function improved_var_export ($variable, $return = false) {
    if ($variable instanceof stdClass) {
        $result = '(object) '.improved_var_export(get_object_vars($variable), true);
    } else if (is_array($variable)) {
        $array = array ();
        foreach ($variable as $key => $value) {
            $array[] = var_export($key, true).' => '.improved_var_export($value, true);
        }
        $result = 'array ('.implode(', ', $array).')';
    } else {
        $result = var_export($variable, true);
    }

    if (!$return) {
        print $result;
        return null;
    } else {
        return $result;
    }
}

// Example usage:
$obj = new stdClass;
$obj->test = 'abc';
$obj->other = 6.2;
$obj->arr = array (1, 2, 3);

improved_var_export((object) array (
    'prop1' => true,
    'prop2' => $obj,
    'assocArray' => array (
        'apple' => 'good',
        'orange' => 'great'
    )
));

/* Output:
(object) array ('prop1' => true, 'prop2' => (object) array ('test' => 'abc', 'other' => 6.2, 'arr' => array (0 => 1, 1 => 2, 2 => 3)), 'assocArray' => array ('apple' => 'good', 'orange' => 'great'))
*/
?>

Note: This function spits out a single line of code, which is useful to save in a cache file to include/eval. It isn't formatted for readability. If you want to print a readable version for debugging purposes, then I would suggest print_r() or var_dump().

down

xzero at elite7hackers dot net ¶

7 years ago

There comes improved version of amazing snippet posted by (spark at limao dot com dot br)  which allows dynamic methods generations and works as versatile extension of StdClass:

This one is faster, optimised for closures, and will work only with closures. Compatible: >= PHP 5.6
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return $this->{$key}->__invoke(... $params);
    }
}

?>

Usage examples:

<?php
$dynamic                = new Dynamic();
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod()
);
?>

This will accept arrays, strings and Closures but is a bit slower due to call_user_func_array
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return call_user_func_array($this->{$key}, $params);
    }
}

?>

Usage examples:
<?php
$dynamic                = new Dynamic();
$dynamic->myMethod      = "thatFunction";
$dynamic->hisMethod     = array($dynamic, "randomInt");
$dynamic->newMethod     = array(SomeClass, "staticMethod");
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod(),
    $dynamic->hisMethod()
);

?>

down

unknown ¶

22 years ago

It's handy to have a array of the reserved classes.....

var_dump (get_declared_classes ());

down

xzero at elite7hackers dot net ¶

7 years ago

There comes improved version of amazing snippet posted by which allows dynamic methods generations and works as versatile extension of StdClass:

This one is faster, optimised for closures, and will work only with closures. Compatible: >= PHP 5.6
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return $this->{$key}->__invoke(... $params);
    }
}

?>

Usage examples:

<?php
$dynamic                = new Dynamic();
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod()
);
?>

This will accept arrays, strings and Closures but is a bit slower due to call_user_func_array
<?php

class Dynamic extends \stdClass
{
    public function __call($key, $params)
    {
        if ( ! isset($this->{$key})) {
            throw new Exception("Call to undefined method " . __CLASS__ . "::" . $key . "()");
        }

        return call_user_func_array($this->{$key}, $params);
    }
}

?>

Usage examples:
<?php
$dynamic                = new Dynamic();
$dynamic->myMethod      = "thatFunction";
$dynamic->hisMethod     = array($dynamic, "randomInt");
$dynamic->newMethod     = array(SomeClass, "staticMethod");
$dynamic->anotherMethod = function () {
    echo "Hey there";
};
$dynamic->randomInt     = function ($min, $max) {
    return mt_rand($min, $max); // random_int($min, $max); // <-- PHP7+
};

var_dump(
    $dynamic->randomInt(1, 11),
    $dynamic->anotherMethod(),
    $dynamic->hisMethod()
);

?>

down

Ashley Dambra ¶

10 years ago

Here a simple class that allow to set anonymous function. It's an optimised class of stdClass.

<?php
class stdObject {
    public function __construct(array $arguments = array()) {
        if (!empty($arguments)) {
            foreach ($arguments as $property => $argument) {
                if ($argument instanceOf Closure) {
                    $this->{$property} = $argument;
                } else {
                    $this->{$property} = $argument;
                }
            }
        }
    }

    public function __call($method, $arguments) {
        if (isset($this->{$method}) && is_callable($this->{$method})) {
            return call_user_func_array($this->{$method}, $arguments);
        } else {
            throw new Exception("Fatal error: Call to undefined method stdObject::{$method}()");
        }
    }
}

$person = new stdObject(array(
    "name" => "nick",
    "age" => 23,
    "friends" => array("frank", "sally", "aaron"),
    "sayHi" => function() {
        return "Hello there";
    }
));

$person->sayHi2 = function() {
    return "Hello there 2";
};

$person->test = function() {
    return "test";
};

var_dump($person->name, $person->test(), $person->sayHi2());
?>