It should be noted that typed properties internally are never initialized to a default null. Unless of course you initialize them to null yourself. That's why you will always going to encounter this error if you try to access them before initialization.
**Typed property foo::$bar must not be accessed before initialization**
<?php
class User
{
public $id;
public string $name; // Typed property (Uninitialized)
public ?string $age = null; // Typed property (Initialized)
}
$user = new User;
var_dump(is_null($user->id)); // bool(true)
var_dump(is_null($user->name)); // PHP Fatal error: Typed property User::$name must not be accessed before initialization
var_dump(is_null($user->age));// bool(true)
?>
Another thing worth noting is that it's not possible to initialize a property of type object to anything other than null. Since the evaluation of properties happens at compile-time and object instantiation happens at runtime. One last thing, callable type is not supported due to its context-dependent behavior.
PHP.mk документација
Нови одлики
Почист и полокален преглед на PHP референцата, со задржана структура од PHP.net и подобра читливост за примери, секции и белешки.
Патека
migration74.new-features.php
Локална патека за оваа страница.
Извор
php.net/manual/en
Оригиналниот HTML се реупотребува и локално се стилизира.
Режим
Прокси + превод во позадина
Кодовите, табелите и белешките остануваат читливи во истиот тек.
Референца
migration74.new-features.php
Нови одлики
Референца за `migration74.new-features.php` со подобрена типографија и навигација.
Нови одлики
PHP јадро
Typed properties
Class properties now support type declarations.
<?php
class User {
public int $id;
public string $name;
}
?>$user->id can only be assigned int вредности и $user->name can only be assigned string values.
Arrow functions
Arrow functions provide a shorthand syntax for defining functions with implicit by-value scope binding.
<?php
$factor = 10;
$nums = array_map(fn($n) => $n * $factor, [1, 2, 3, 4]);
// $nums = array(10, 20, 30, 40);
?>Limited return type covariance and argument type contravariance
The following code will now work:
<?php
class A {}
class B extends A {}
class Producer {
public function method(): A {}
}
class ChildProducer extends Producer {
public function method(): B {}
}
?><?php
/**
* These classes satisfy the LSP requirements, because C is a subtype of A.
* However, at the time class B is declared, class C is not yet available
*/
class A
{
public function method(): A {}
}
class B extends A
{
// Fatal error: Could not check compatibility between B::method():C and
// A::method(): A, because class С is not available
public function method(): С {}
}
class C extends B {}
?>Null coalescing assignment operator
<?php
$array['key'] ??= computeDefault();
// is roughly equivalent to
if (!isset($array['key'])) {
$array['key'] = computeDefault();
}
?>Unpacking inside arrays
<?php
$parts = ['apple', 'pear'];
$fruits = ['banana', 'orange', ...$parts, 'watermelon'];
// ['banana', 'orange', 'apple', 'pear', 'watermelon'];
?>Numeric literal separator
Numeric literals can contain underscores between digits.
<?php
6.674_083e-11; // float
299_792_458; // decimal
0xCAFE_F00D; // hexadecimal
0b0101_1111; // binary
?>Weak references
Weak references allow the programmer to retain a reference to an object that does not prevent the object from being destroyed.
Allow exceptions from __toString()
Throwing exceptions from __toString() is now permitted. Previously this resulted in a fatal error. Existing recoverable fatal errors in string conversions have been converted to Грешка exceptions.
CURL
CURLFile now supports stream wrappers in addition to plain file names, if the extension has been built against libcurl >= 7.56.0.
Филтер
На FILTER_VALIDATE_FLOAT filter now supports the
min_range and max_range
options, with the same semantics as FILTER_VALIDATE_INT.
FFI
FFI is a new extension, which provides a simple way to call native functions, access native variables, and create/access data structures defined in C libraries.
GD
Додаден е IMG_FILTER_SCATTER image filter to apply a scatter filter to images.
Хеш
Додадено crc32c hash using Castagnoli's polynomial. This CRC32 variant is used by storage systems, such as iSCSI, SCTP, Btrfs and ext4.
Повеќебајтни низи
Додаден е mb_str_split() function, which provides the same functionality as str_split(), but operating on code points rather than bytes.
OPcache
Support for preloading code е додадена.
Регуларни изрази (компатибилни со Perl)
На preg_replace_callback() and preg_replace_callback_array()
functions now accept an additional flags argument, with support for the
PREG_OFFSET_CAPTURE and PREG_UNMATCHED_AS_NULL flags. This influences the format of the matches array passed to the callback function.
PDO
The username and password can now be specified as part of the PDO DSN for the mysql, mssql, sybase, dblib, firebird and oci drivers. Previously this was only supported by the pgsql driver. If a username/password is specified both in the constructor and the DSN, the constructor takes precedence.
It is now possible to escape question marks in SQL queries to avoid them being interpreted as parameter placeholders. Writing ??
allows sending a single question mark to the database and e.g. use the PostgreSQL JSON key exists (?) оператор.
PDO_OCI
Некои драјвери можеби не имплементираат is now available.
PDO_SQLite
PDOStatement::getAttribute(PDO::SQLITE_ATTR_READONLY_STATEMENT)
allows checking whether the statement is read-only, i.e. if it doesn't modify the database.
PDO::setAttribute(PDO::SQLITE_ATTR_EXTENDED_RESULT_CODES, true)
enables the use of SQLite3 extended result codes in Пример #1 Преземање на SQLSTATE код
and - Преземи го SQLSTATE поврзан со последната операција на рачката на изјавата.
SQLite3
Додадено SQLite3::lastExtendedErrorCode() to fetch the last extended result code.
Додадено SQLite3::enableExtendedResultCodes($enable = true), which will make SQLite3::lastErrorCode()
return extended result codes.
Стандардно
strip_tags() with array of tag names
strip_tags() now also accepts an array of allowed tags: instead of strip_tags($str, '<a><p>')
you can now write strip_tags($str, ['a', 'p']).
Custom object serialization
A new mechanism for custom object serialization has been added, which uses two new magic methods: __serialize
and __unserialize.
<?php
// Returns array containing all the necessary state of the object.
public function __serialize(): array
{
}
// Restores the object state from the given data array.
public function __unserialize(array $data): void
{
}
?>Array merge functions without arguments
array_merge() and array_merge_recursive()
may now be called without any arguments, in which case they will return an empty array. This is useful in conjunction with the spread operator, e.g. array_merge(...$arrays).
proc_open() function
proc_open() now accepts an array instead of a string for the command. In this case the process will be opened directly (without going through a shell) and PHP will take care of any necessary argument escaping.
<?php
proc_open(['php', '-r', 'echo "Hello World\n";'], $descriptors, $pipes);
?>
proc_open() сега поддржува
redirect and null descriptors.
<?php
// Like 2>&1 on the shell
proc_open($cmd, [1 => ['pipe', 'w'], 2 => ['redirect', 1]], $pipes);
// Like 2>/dev/null or 2>nul on the shell
proc_open($cmd, [1 => ['pipe', 'w'], 2 => ['null']], $pipes);
?>argon2i(d) without libargon
password_hash() now has the argon2i and argon2id implementations from the sodium extension when PHP is built without libargon.
Белешки од корисници 2 забелешки
Rain ¶
пред 6 години
wow-apps.pro ¶
пред 6 години
<?php
// How to get property type? For example for testing:
class Foo
{
private int $num;
private bool $isPositive;
private $notes;
}
$reflection = new \ReflectionClass(Foo::class);
$classProperties = $reflection->getProperties(\ReflectionProperty::IS_PRIVATE);
foreach ($classProperties as $classProperty) {
var_dump((string) $classProperty->getType());
}
/**
* Result:
* "int"
* "bool"
* ""
*/