new-features.xml

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<sect1 xml:id="migration74.new-features" xmlns:xlink="http://www.w3.org/1999/xlink">
 <title>Nuevas características</title>

 <sect2 xml:id="migration74.new-features.core">
  <title>PHP Core</title>

  <sect3 xml:id="migration74.new-features.core.typed-properties">
   <title>Typed properties</title>

   <para>
    Class properties now support type declarations.
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
class User {
    public int $id;
    public string $name;
}
?>
]]>
     </programlisting>
    </informalexample>
    The above example will enforce that <literal>$user->id</literal> can only be
    assigned <type>int</type> values and <literal>$user->name</literal> can
    only be assigned <type>string</type> values.
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.core.arrow-functions">
   <title>Arrow functions</title>

   <para>
    <link linkend="functions.arrow">Arrow functions</link> provide a
    shorthand syntax for defining functions
    with implicit by-value scope binding.

    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
$factor = 10;
$nums = array_map(fn($n) => $n * $factor, [1, 2, 3, 4]);
// $nums = array(10, 20, 30, 40);
?>
]]>
     </programlisting>
    </informalexample>
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.core.type-variance">
   <title>Limited return type covariance and argument type contravariance</title>

   <para>
    The following code will now work:
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
class A {}
class B extends A {}

class Producer {
    public function method(): A {}
}
class ChildProducer extends Producer {
    public function method(): B {}
}
?>
]]>
     </programlisting>
    </informalexample>
    Full variance support is only available if autoloading is used. Inside a
    single file only non-cyclic type references are possible, because all
    classes need to be available before they are referenced.
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.core.null-coalescing-assignment-operator">
   <title>Null coalescing assignment operator</title>

   <para>
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
$array['key'] ??= computeDefault();
// is roughly equivalent to
if (!isset($array['key'])) {
    $array['key'] = computeDefault();
}
?>
]]>
     </programlisting>
    </informalexample>
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.core.unpack-inside-array">
   <title>Unpacking inside arrays</title>

   <para>
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
$parts = ['apple', 'pear'];
$fruits = ['banana', 'orange', ...$parts, 'watermelon'];
// ['banana', 'orange', 'apple', 'pear', 'watermelon'];
?>
]]>
     </programlisting>
    </informalexample>
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.core.numeric-literal-separator">
   <title>Numeric literal separator</title>

   <para>
    Numeric literals can contain underscores between digits.
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
6.674_083e-11; // float
299_792_458;   // decimal
0xCAFE_F00D;   // hexadecimal
0b0101_1111;   // binary
?>
]]>
     </programlisting>
    </informalexample>
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.core.weakreference">
   <title>Weak references</title>

   <para>
    Weak references allow the programmer to retain a reference to an object
    that does not prevent the object from being destroyed.
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.core.tostring-exceptions">
   <title>Allow exceptions from __toString()</title>

   <para>
    Throwing exceptions from <link linkend="object.tostring">__toString()</link>
    is now permitted. Previously this resulted in a fatal error. Existing
    recoverable fatal errors in string conversions have been converted to
    <classname>Error</classname> exceptions.
   </para>
  </sect3>

 </sect2>

 <sect2 xml:id="migration74.new-features.curl">
  <title>CURL</title>

  <para>
   <classname>CURLFile</classname> now supports stream wrappers in addition
   to plain file names, if the extension has been built against libcurl &gt;= 7.56.0.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.filter">
  <title>Filter</title>

  <para>
   The <constant>FILTER_VALIDATE_FLOAT</constant> filter now supports the
   <literal>min_range</literal> and <literal>max_range</literal>
   options, with the same semantics as <constant>FILTER_VALIDATE_INT</constant>.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.ffi">
  <title>FFI</title>

  <para>
   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.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.gd">
  <title>GD</title>

  <para>
   Added the <constant>IMG_FILTER_SCATTER</constant> image filter
   to apply a scatter filter to images.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.hash">
  <title>Hash</title>

  <para>
   Added <literal>crc32c</literal> hash using Castagnoli's polynomial.
   This CRC32 variant is used by storage systems, such as
   iSCSI, SCTP, Btrfs and ext4.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.mbstring">
  <title>Multibyte String</title>

  <para>
   Added the <function>mb_str_split</function> function, which provides
   the same functionality as <function>str_split</function>, but operating
   on code points rather than bytes.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.opcache">
  <title>OPcache</title>

  <para>
   <link linkend="opcache.preloading">Support for preloading code</link> has been added.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.pcre">
  <title>Regular Expressions (Perl-Compatible)</title>

  <para>
   The <function>preg_replace_callback</function> and <function>preg_replace_callback_array</function>
   functions now accept an additional <parameter>flags</parameter> argument, with support for the
   <constant>PREG_OFFSET_CAPTURE</constant> and <constant>PREG_UNMATCHED_AS_NULL</constant> flags.
   This influences the format of the matches array passed to to the callback function.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.pdo">
  <title>PDO</title>

  <para>
   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.
  </para>
  <para>
   It is now possible to escape question marks in SQL queries to avoid them
   being interpreted as parameter placeholders. Writing <literal>??</literal>
   allows sending a single question mark to the database and e.g. use the
   PostgreSQL JSON key exists (<literal>?</literal>) operator.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.pdo_oci">
  <title>PDO_OCI</title>

  <para>
   <methodname>PDOStatement::getColumnMeta</methodname> is now available.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.pdo_sqlite">
  <title>PDO_SQLite</title>

  <para>
   <literal>PDOStatement::getAttribute(PDO::SQLITE_ATTR_READONLY_STATEMENT)</literal>
   allows checking whether the statement is read-only, i.e. if it doesn't modify
   the database.
  </para>
  <para>
   <literal>PDO::setAttribute(PDO::SQLITE_ATTR_EXTENDED_RESULT_CODES, true)</literal>
   enables the use of SQLite3 extended result codes in <function>PDO::errorInfo</function>
   and <function>PDOStatement::errorInfo</function>.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.sqlite3">
  <title>SQLite3</title>

  <para>
   Added <methodname>SQLite3::lastExtendedErrorCode</methodname>
   to fetch the last extended result code.
  </para>
  <para>
   Added <literal>SQLite3::enableExtendedResultCodes($enable = true)</literal>,
   which will make <methodname>SQLite3::lastErrorCode</methodname>
   return extended result codes.
  </para>
 </sect2>

 <sect2 xml:id="migration74.new-features.standard">
  <title>Standard</title>

  <sect3 xml:id="migration74.new-features.standard.strip-tags">
   <title>strip_tags() with array of tag names</title>
   <para>
    <function>strip_tags</function> now also accepts an array of allowed tags:
    instead of <literal>strip_tags($str, '&lt;a&gt;&lt;p&gt;')</literal>
    you can now write <literal>strip_tags($str, ['a', 'p'])</literal>.
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.standard.magic-serialize">
   <title>Custom object serialization</title>
   <para>
    A new mechanism for custom object serialization has been added, which
    uses two new magic methods: <literal>__serialize</literal>
    and <literal>__unserialize</literal>.
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?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;
?>
]]>
     </programlisting>
    </informalexample>
    The new serialization mechanism supersedes the
    <interfacename>Serializable</interfacename> interface,
    which will be deprecated in the future.
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.standard.array-merge-no-args">
   <title>Array merge functions without arguments</title>
   <para>
    <function>array_merge</function> and <function>array_merge_recursive</function>
    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. <literal>array_merge(...$arrays)</literal>.
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.standard.proc-open">
   <title><function>proc_open</function> function</title>
   <para>
    <function>proc_open</function> 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.
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
proc_open(['php', '-r', 'echo "Hello World\n";'], $descriptors, $pipes);
?>
]]>
     </programlisting>
    </informalexample>
   </para>
   <para>
    <function>proc_open</function> now supports
    <literal>redirect</literal> and <literal>null</literal> descriptors.
    <informalexample>
     <programlisting role="php">
<![CDATA[
<?php
// Like 2>&1 on the shell
proc_open($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);
?>
]]>
     </programlisting>
    </informalexample>
   </para>
  </sect3>

  <sect3 xml:id="migration74.new-features.standard.sodium-argon-hash">
   <title>argon2i(d) without libargon</title>
   <para>
    <function>password_hash</function> now has the argon2i and argon2id implementations
    from the sodium extension when PHP is built without libargon.
   </para>
  </sect3>

 </sect2>

</sect1>

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