php-doc-en/appendices/migration56/new-features.xml
Christoph Michael Becker c9b1de1c12 Link to internal phpdbg docs
This solves the issue that we're linking to an external site whose cert
is expired (user note 123470), and is generally the way forward[1].

We do not yet remove the url.phpdbg.docs entity, since it is used by
multiple active translations.

[1] <http://news.php.net/php.doc/969386971>f

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@346451 c90b9560-bf6c-de11-be94-00142212c4b1
2018-12-28 14:39:45 +00:00

452 lines
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XML

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<sect1 xml:id="migration56.new-features" xmlns:xlink="http://www.w3.org/1999/xlink">
<title>New features</title>
<sect2 xml:id="migration56.new-features.const-scalar-exprs">
<title>Constant expressions</title>
<para>
It is now possible to provide a scalar expression involving numeric and
string literals and/or constants in contexts where PHP previously expected
a static value, such as constant and property declarations and default
function arguments.
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
const ONE = 1;
const TWO = ONE * 2;
class C {
const THREE = TWO + 1;
const ONE_THIRD = ONE / self::THREE;
const SENTENCE = 'The value of THREE is '.self::THREE;
public function f($a = ONE + self::THREE) {
return $a;
}
}
echo (new C)->f()."\n";
echo C::SENTENCE;
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
4
The value of THREE is 3
]]>
</screen>
</informalexample>
<para>
It is also now possible to define a constant <type>array</type> using the
<literal>const</literal> keyword:
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
const ARR = ['a', 'b'];
echo ARR[0];
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
a
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.variadics">
<title>Variadic functions via <literal>...</literal></title>
<para>
<link linkend="functions.variable-arg-list">Variadic functions</link> can
now be implemented using the <literal>...</literal> operator, instead of
relying on <function>func_get_args</function>.
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
function f($req, $opt = null, ...$params) {
// $params is an array containing the remaining arguments.
printf('$req: %d; $opt: %d; number of params: %d'."\n",
$req, $opt, count($params));
}
f(1);
f(1, 2);
f(1, 2, 3);
f(1, 2, 3, 4);
f(1, 2, 3, 4, 5);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
$req: 1; $opt: 0; number of params: 0
$req: 1; $opt: 2; number of params: 0
$req: 1; $opt: 2; number of params: 1
$req: 1; $opt: 2; number of params: 2
$req: 1; $opt: 2; number of params: 3
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.splat">
<title>Argument unpacking via <literal>...</literal></title>
<para>
<link linkend="language.types.array">Arrays</link> and
<interfacename>Traversable</interfacename> objects can be unpacked into
argument lists when calling functions by using the <literal>...</literal>
operator. This is also known as the splat operator in other languages,
including Ruby.
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
function add($a, $b, $c) {
return $a + $b + $c;
}
$operators = [2, 3];
echo add(1, ...$operators);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
6
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.exponentiation">
<title>Exponentiation via <literal>**</literal></title>
<para>
A right associative <literal>**</literal> operator has been added to
support exponentiation, along with a <literal>**=</literal> shorthand
assignment operator.
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
printf("2 ** 3 == %d\n", 2 ** 3);
printf("2 ** 3 ** 2 == %d\n", 2 ** 3 ** 2);
$a = 2;
$a **= 3;
printf("a == %d\n", $a);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
2 ** 3 == 8
2 ** 3 ** 2 == 512
a == 8
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.use">
<title><literal>use function</literal> and <literal>use const</literal></title>
<para>
The
<link linkend="language.namespaces.importing"><literal>use</literal></link>
operator has been extended to support importing functions and constants in
addition to classes. This is achieved via the
<literal>use function</literal> and <literal>use const</literal>
constructs, respectively.
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
namespace Name\Space {
const FOO = 42;
function f() { echo __FUNCTION__."\n"; }
}
namespace {
use const Name\Space\FOO;
use function Name\Space\f;
echo FOO."\n";
f();
}
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
42
Name\Space\f
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.phpdbg">
<title>phpdbg</title>
<para>
PHP now includes an interactive debugger called phpdbg implemented as a
SAPI module. For more information, please visit the
<link linkend="book.phpdbg">phpdbg documentation</link>.
</para>
</sect2>
<sect2 xml:id="migration56.new-features.default-encoding">
<title>Default character encoding</title>
<para>
<link linkend="ini.default-charset">default_charset</link> is now used as
the default character set for the <function>htmlentities</function>,
<function>html_entity_decode</function> and
<function>htmlspecialchars</function> functions. Note that if the (now
deprecated) iconv and mbstring encoding settings are set, they will take
precedence over default_charset for iconv and mbstring functions,
respectively.
</para>
<para>
The default value for this setting is <literal>UTF-8</literal>.
</para>
</sect2>
<sect2 xml:id="migration56.new-features.reusable-input">
<title><link linkend="wrappers.php.input"><literal>php://input</literal></link> is reusable</title>
<para>
<link linkend="wrappers.php.input"><literal>php://input</literal></link>
may now be reopened and read as many times as required. This work has also
resulted in a major reduction in the amount of memory required to deal
with POST data.
</para>
</sect2>
<sect2 xml:id="migration56.new-features.large-file">
<title>Large file uploads</title>
<para>
Files larger than 2 gigabytes in size are now accepted.
</para>
</sect2>
<sect2 xml:id="migration56.new-features.gmp">
<title><link linkend="book.gmp">GMP</link> supports operator overloading</title>
<para>
<link linkend="book.gmp">GMP</link> objects now support operator
overloading and casting to scalar types. This allows for more expressive
code using GMP:
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
$a = gmp_init(42);
$b = gmp_init(17);
if (version_compare(PHP_VERSION, '5.6', '<')) {
echo gmp_intval(gmp_add($a, $b)), PHP_EOL;
echo gmp_intval(gmp_add($a, 17)), PHP_EOL;
echo gmp_intval(gmp_add(42, $b)), PHP_EOL;
} else {
echo $a + $b, PHP_EOL;
echo $a + 17, PHP_EOL;
echo 42 + $b, PHP_EOL;
}
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
59
59
59
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.hash-equals">
<title><function>hash_equals</function> for timing attack safe string comparison</title>
<para>
The <function>hash_equals</function> function has been added to compare
two strings in constant time. This should be used to mitigate timing
attacks; for instance, when testing <function>crypt</function> password
hashes (assuming that you are unable to use
<function>password_hash</function> and
<function>password_verify</function>, which aren't susceptible to timing
attacks).
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
$expected = crypt('12345', '$2a$07$usesomesillystringforsalt$');
$correct = crypt('12345', '$2a$07$usesomesillystringforsalt$');
$incorrect = crypt('1234', '$2a$07$usesomesillystringforsalt$');
var_dump(hash_equals($expected, $correct));
var_dump(hash_equals($expected, $incorrect));
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
bool(true)
bool(false)
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.debuginfo">
<title><literal>__debugInfo()</literal></title>
<para>
The <link linkend="language.oop5.magic.debuginfo">__debugInfo()</link>
magic method has been added to allow objects to change the properties and
values that are shown when the object is output using
<function>var_dump</function>.
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
class C {
private $prop;
public function __construct($val) {
$this->prop = $val;
}
public function __debugInfo() {
return [
'propSquared' => $this->prop ** 2,
];
}
}
var_dump(new C(42));
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
object(C)#1 (1) {
["propSquared"]=>
int(1764)
}
]]>
</screen>
</informalexample>
</sect2>
<sect2 xml:id="migration56.new-features.gost">
<title>gost-crypto hash algorithm</title>
<para>
The <literal>gost-crypto</literal> hash algorithm has been added. This
implements the GOST hash function using the CryptoPro S-box tables as
specified by
<link xlink:href="&url.rfc;4357">RFC 4357, section 11.2</link>.
</para>
</sect2>
<sect2 xml:id="migration56.new-features.openssl">
<title>SSL/TLS improvements</title>
<para>
A wide range of improvements have been made to the SSL/TLS support in PHP
5.6. These include
<link linkend="migration56.incompatible.peer-verification">enabling peer verification by default</link>,
supporting certificate fingerprint matching, mitigating against TLS
renegotiation attacks, and many new
<link linkend="context.ssl">SSL context options</link> to allow more fine
grained control over protocol and verification settings when using
encrypted streams.
</para>
<para>
These changes are described in more detail in the
<link linkend="migration56.openssl">OpenSSL changes in PHP 5.6.x</link>
section of this migration guide.
</para>
</sect2>
<sect2 xml:id="migration56.new-features.postgresql">
<title><link linkend="book.pgsql">pgsql</link> async support</title>
<para>
The <link linkend="book.pgsql">pgsql</link> extension now supports
asynchronous connections and queries, thereby enabling non-blocking
behaviour when interacting with PostgreSQL databases. Asynchronous
connections may be established via the
<constant>PGSQL_CONNECT_ASYNC</constant> constant, and the new
<function>pg_connect_poll</function>, <function>pg_socket</function>,
<function>pg_consume_input</function> and <function>pg_flush</function>
functions may be used to handle asynchronous connections and queries.
</para>
</sect2>
</sect1>
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