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</div><hr /><div id="migration55.new-features" class="sect1">
<h2 class="title">New features</h2>
<div class="sect2" id="migration55.new-features.generators">
<h3 class="title"><a href="language.generators.html" class="link">Generators</a> added</h3>
<p class="para">
Support for <a href="language.generators.html" class="link">generators</a> has been
added via the <strong class="command">yield</strong> keyword. Generators provide an easy
way to implement simple iterators without the overhead or complexity of
implementing a class that implements the <a href="class.iterator.html" class="classname">Iterator</a>
interface.
</p>
<p class="para">
A simple example that reimplements the <span class="function"><a href="function.range.html" class="function">range()</a></span>
function as a generator (at least for positive <em>step</em>
values):
</p>
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">xrange</span><span style="color: #007700">(</span><span style="color: #0000BB">$start</span><span style="color: #007700">, </span><span style="color: #0000BB">$limit</span><span style="color: #007700">, </span><span style="color: #0000BB">$step </span><span style="color: #007700">= </span><span style="color: #0000BB">1</span><span style="color: #007700">) {<br /> for (</span><span style="color: #0000BB">$i </span><span style="color: #007700">= </span><span style="color: #0000BB">$start</span><span style="color: #007700">; </span><span style="color: #0000BB">$i </span><span style="color: #007700"><= </span><span style="color: #0000BB">$limit</span><span style="color: #007700">; </span><span style="color: #0000BB">$i </span><span style="color: #007700">+= </span><span style="color: #0000BB">$step</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">yield $i</span><span style="color: #007700">;<br /> }<br />}<br /><br />echo </span><span style="color: #DD0000">'Single digit odd numbers: '</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/*<br /> * Note that an array is never created or returned,<br /> * which saves memory.<br /> */<br /></span><span style="color: #007700">foreach (</span><span style="color: #0000BB">xrange</span><span style="color: #007700">(</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">9</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">) as </span><span style="color: #0000BB">$number</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"</span><span style="color: #0000BB">$number</span><span style="color: #DD0000"> "</span><span style="color: #007700">;<br />}<br /><br />echo </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">The above example will output:</p>
<div class="example-contents screen">
<div class="cdata"><pre>
Single digit odd numbers: 1 3 5 7 9
</pre></div>
</div>
</div>
</div>
<div class="sect2" id="migration55.new-features.finally">
<h3 class="title"><a href="language.exceptions.html" class="link"><em>finally</em></a> keyword added</h3>
<p class="para">
<em>try</em>-<em>catch</em> blocks now support a
<a href="language.exceptions.html" class="link"><em>finally</em></a>
block for code that should be run regardless of whether an exception has
been thrown or not.
</p>
</div>
<div class="sect2" id="migration55.new-features.password">
<h3 class="title">New password hashing API</h3>
<p class="para">
A <a href="book.password.html" class="link">new password hashing API</a> that makes
it easier to securely hash and manage passwords using the same underlying
library as <span class="function"><a href="function.crypt.html" class="function">crypt()</a></span> in PHP has been added. See the
documentation for <span class="function"><a href="function.password-hash.html" class="function">password_hash()</a></span> for more detail.
</p>
</div>
<div class="sect2" id="migration55.new-features.foreach-list">
<h3 class="title"><a href="control-structures.foreach.html" class="link"><em>foreach</em></a> now supports <span class="function"><a href="function.list.html" class="function">list()</a></span></h3>
<p class="para">
The <a href="control-structures.foreach.html" class="link">foreach</a> control
structure now supports unpacking nested arrays into separate variables via
the <span class="function"><a href="function.list.html" class="function">list()</a></span> construct. For example:
</p>
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$array </span><span style="color: #007700">= [<br /> [</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">],<br /> [</span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">4</span><span style="color: #007700">],<br />];<br /><br />foreach (</span><span style="color: #0000BB">$array </span><span style="color: #007700">as list(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">$b</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"A: </span><span style="color: #0000BB">$a</span><span style="color: #DD0000">; B: </span><span style="color: #0000BB">$b</span><span style="color: #DD0000">\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">The above example will output:</p>
<div class="example-contents screen">
<div class="cdata"><pre>
A: 1; B: 2
A: 3; B: 4
</pre></div>
</div>
</div>
<p class="para">
Further documentation is available on the
<a href="control-structures.foreach.html#control-structures.foreach.list" class="link">foreach</a> manual
page.
</p>
</div>
<div class="sect2" id="migration55.new-features.empty">
<h3 class="title"> <span class="function"><a href="function.empty.html" class="function">empty()</a></span> supports arbitrary expressions</h3>
<p class="para">
Passing an arbitrary expression instead of a variable to
<span class="function"><a href="function.empty.html" class="function">empty()</a></span> is now supported. For example:
</p>
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">always_false</span><span style="color: #007700">() {<br /> return </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br />}<br /><br />if (empty(</span><span style="color: #0000BB">always_false</span><span style="color: #007700">())) {<br /> echo </span><span style="color: #DD0000">"This will be printed.\n"</span><span style="color: #007700">;<br />}<br /><br />if (empty(</span><span style="color: #0000BB">true</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"This will not be printed.\n"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">The above example will output:</p>
<div class="example-contents screen">
<div class="cdata"><pre>
This will be printed.
</pre></div>
</div>
</div>
</div>
<div class="sect2" id="migration55.new-features.const-dereferencing">
<h3 class="title"><span class="type"><a href="language.types.array.html" class="type array">array</a></span> and <span class="type"><a href="language.types.string.html" class="type string">string</a></span> literal dereferencing</h3>
<p class="para">
<span class="type"><a href="language.types.array.html" class="type Array">Array</a></span> and <span class="type"><a href="language.types.string.html" class="type string">string</a></span> literals can now be
dereferenced directly to access individual elements and characters:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">'Array dereferencing: '</span><span style="color: #007700">;<br />echo [</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">];<br />echo </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br />echo </span><span style="color: #DD0000">'String dereferencing: '</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">'PHP'</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">];<br />echo </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">The above example will output:</p>
<div class="example-contents screen">
<div class="cdata"><pre>
Array dereferencing: 1
String dereferencing: P
</pre></div>
</div>
</div>
</p>
</div>
<div class="sect2" id="migration55.new-features.class-name">
<h3 class="title">Class name resolution via <a href="language.oop5.basic.html#language.oop5.basic.class.class" class="link">::class</a></h3>
<p class="para">
It is possible to use <em>ClassName::class</em> to get a fully
qualified name of class <em>ClassName</em>. For example:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">namespace </span><span style="color: #0000BB">Name</span><span style="color: #007700">\</span><span style="color: #0000BB">Space</span><span style="color: #007700">;<br />class </span><span style="color: #0000BB">ClassName </span><span style="color: #007700">{}<br /><br />echo </span><span style="color: #0000BB">ClassName</span><span style="color: #007700">::class;<br /><br />echo </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">The above example will output:</p>
<div class="example-contents screen">
<div class="cdata"><pre>
Name\Space\ClassName
</pre></div>
</div>
</div>
</p>
</div>
<div class="sect2" id="migration55.new-features.opcache">
<h3 class="title"><a href="book.opcache.html" class="link">OPcache</a> extension added</h3>
<p class="para">
The Zend Optimiser+ opcode cache has been added to PHP as the new
<a href="book.opcache.html" class="link">OPcache extension</a>.
OPcache improves PHP performance by storing precompiled script bytecode in
shared memory, thereby removing the need for PHP to load and parse scripts
on each request. See
<a href="opcache.installation.html" class="link">the installation instructions</a>
for more detail on enabling and using OPcache.
</p>
</div>
<div class="sect2" id="migration55.new-features.non-scalar-iterator-keys">
<h3 class="title"><a href="control-structures.foreach.html" class="link"><em>foreach</em></a> now supports non-scalar keys</h3>
<p class="para">
<a href="control-structures.foreach.html" class="link">foreach</a> now supports
keys of any type. While non-scalar keys cannot occur in native PHP arrays,
it is possible for <span class="methodname"><a href="iterator.key.html" class="methodname">Iterator::key()</a></span> to return a
value of any type, and this will now be handled correctly.
</p>
</div>
<div class="sect2" id="migration55.new-features.windows-apache">
<h3 class="title">Apache 2.4 handler supported on Windows</h3>
<p class="para">
The Apache 2.4 handler SAPI is now supported on Windows.
</p>
</div>
<div class="sect2" id="migration55.new-features.gd">
<h3 class="title">Improvements to GD</h3>
<p class="para">
Various improvements have been made to the GD extension, these include:
</p>
<ul class="itemizedlist">
<li class="listitem">
<span class="simpara">
Flipping support using the new <span class="function"><a href="function.imageflip.html" class="function">imageflip()</a></span>
function.
</span>
</li>
<li class="listitem">
<span class="simpara">
Advanced cropping support using the <span class="function"><a href="function.imagecrop.html" class="function">imagecrop()</a></span> &
<span class="function"><a href="function.imagecropauto.html" class="function">imagecropauto()</a></span> functions.
</span>
</li>
<li class="listitem">
<span class="simpara">
WebP read and write support using <span class="function"><a href="function.imagecreatefromwebp.html" class="function">imagecreatefromwebp()</a></span>
& <span class="function"><a href="function.imagewebp.html" class="function">imagewebp()</a></span> respectively.
</span>
</li>
</ul>
</div>
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