language/basic-syntax.xml
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everything outside of a pair of opening and closing tags is ignored by the
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PHP parser.
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</para>
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<para>
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PHP includes a short echo tag <literal><?=</literal> which is a
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short-hand to the more verbose <code><?php echo</code>.
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</para>
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<para>
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<example>
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<title>PHP Opening and Closing Tags</title>
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<programlisting role="php">
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<![CDATA[
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1. <?php echo 'if you want to serve PHP code in XHTML or XML documents,
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use these tags'; ?>
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2. You can use the short echo tag to <?= 'print this string' ?>.
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It's equivalent to <?php echo 'print this string' ?>.
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3. <? echo 'this code is within short tags, but will only work '.
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'if short_open_tag is enabled'; ?>
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]]>
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</programlisting>
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</example>
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</para>
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<para>
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PHP also allows for short open tag <literal><?</literal> (which is
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discouraged since it is only available if enabled using the
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<link linkend="ini.short-open-tag">short_open_tag</link> &php.ini;
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configuration file directive, or if PHP was configured with the
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<option>--enable-short-tags</option> option).
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Short tags (example three) are available by default but can be disabled
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either via the <link linkend="ini.short-open-tag">short_open_tag</link>
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&php.ini; configuration file directive, or are disabled by default if
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PHP is built with the <option>--disable-short-tags</option> configuration.
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</para>
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<para>
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<note>
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<para>
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As short tags can be disabled it is recommended to only use the normal
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tags (<code><?php ?></code> and <code><?= ?></code>) to
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maximise compatibility.
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</para>
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</note>
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</para>
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<para>
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If a file contains only PHP code, it is preferable to omit the PHP closing tag
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at the end of the file. This prevents accidental whitespace or new lines
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being added after the PHP closing tag, which may cause unwanted effects
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</programlisting>
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</informalexample>
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</para>
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<para>
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<table>
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&reftitle.changelog;
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>7.0.0</entry>
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<entry>
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The ASP tags <code><%</code>, <code>%></code>,
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<code><%=</code>, and the script tag
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<code><script language="php"></code> are removed from PHP.
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</entry>
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</row>
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<row>
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<entry>5.4.0</entry>
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<entry>
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The tag <?= is always available regardless of the short_open_tag ini setting.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</para>
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</sect1>
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<sect1 xml:id="language.basic-syntax.phpmode">
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<title>Escaping from HTML</title>
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<para>
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</programlisting>
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</informalexample>
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This works as expected, because when the PHP interpreter hits the ?> closing
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tags, it simply starts outputting whatever it finds (except for an
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tags, it simply starts outputting whatever it finds (except for the
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immediately following newline - see
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<link linkend="language.basic-syntax.instruction-separation">instruction separation</link>)
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until it hits another opening tag unless in the middle of a conditional
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<function>echo</function> or <function>print</function>.
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</para>
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<para>
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In PHP 5, there are up to five different pairs of opening and closing tags
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available in PHP, depending on how PHP is configured. Two of these,
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<code><?php ?></code> and
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<code><script language="php"> </script></code>, are always
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available. There is also the short echo tag <code><?= ?></code>,
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which is always available in PHP 5.4.0 and later.
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</para>
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<para>
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The other two are short tags and <productname>ASP</productname> style
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tags. As such, while some people find short tags and
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<productname>ASP</productname> style tags convenient, they are less
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portable, and generally not recommended.
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<note>
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<para>
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Also note that if you are embedding PHP within XML or XHTML
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you will need to use the <?php ?> tags to remain
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compliant with standards.
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If PHP is embeded within XML or XHTML the normal PHP
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<code><?php ?></code> must be used to remain compliant
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with the standards.
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</para>
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</note>
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</para>
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</sect1>
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<sect1 xml:id="language.basic-syntax.instruction-separation">
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<title>Instruction separation</title>
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<para>
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PHP 7 removes support for <productname>ASP</productname> tags and
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<code><script language="php"></code> tags. As such, we recommend
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only using <code><?php ?></code> and <code><?= ?></code> when
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writing PHP code to maximise compatibility.
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As in C or Perl, PHP requires instructions to be terminated
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with a semicolon at the end of each statement. The closing tag
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of a block of PHP code automatically implies a semicolon; you
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do not need to have a semicolon terminating the last line of a
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PHP block. The closing tag for the block will include the immediately
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trailing newline if one is present.
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</para>
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<para>
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<example>
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<title>PHP Opening and Closing Tags</title>
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<title>Example showing the closing tag encompassing the trailing newline</title>
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<programlisting role="php">
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<![CDATA[
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1. <?php echo 'if you want to serve PHP code in XHTML or XML documents,
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use these tags'; ?>
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2. You can use the short echo tag to <?= 'print this string' ?>.
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It's always enabled in PHP 5.4.0 and later, and is equivalent to
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<?php echo 'print this string' ?>.
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3. <? echo 'this code is within short tags, but will only work '.
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'if short_open_tag is enabled'; ?>
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4. <script language="php">
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echo 'some editors (like FrontPage) don\'t
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like processing instructions within these tags';
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</script>
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This syntax is removed in PHP 7.0.0.
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5. <% echo 'You may optionally use ASP-style tags'; %>
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Code within these tags <%= $variable; %> is a shortcut for this code <% echo $variable; %>
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Both of these syntaxes are removed in PHP 7.0.0.
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<?php echo "Some text"; ?>
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No newline
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<?= "But newline now" ?>
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]]>
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</programlisting>
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&example.outputs;
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<screen>
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<![CDATA[
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Some textNo newline
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But newline now
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]]>
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</screen>
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</example>
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</para>
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<para>
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Short tags (example three) are only available when they are
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enabled via the <link linkend="ini.short-open-tag">short_open_tag</link>
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&php.ini; configuration file directive, or if PHP was configured
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with the <option>--enable-short-tags</option> option.
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</para>
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<para>
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<productname>ASP</productname> style tags (example five) are only
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available when they are enabled via the
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<link linkend="ini.asp-tags">asp_tags</link> &php.ini; configuration file
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directive, and have been removed in PHP 7.0.0.
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</para>
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<para>
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<note>
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<para>
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Using short tags should be avoided when developing applications
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or libraries that are meant for redistribution, or deployment on
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PHP servers which are not under your control, because short tags
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may not be supported on the target server. For portable,
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redistributable code, be sure not to use short tags.
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</para>
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</note>
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<note>
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<para>
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In PHP 5.2 and earlier, the parser does not allow the
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<literal><?php</literal> opening tag to be the only thing in a file.
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This is allowed as of PHP 5.3 provided there are one or more whitespace
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characters after the opening tag.
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</para>
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</note>
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<note>
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<para>
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Starting with PHP 5.4, short echo tag <literal><?=</literal> is always recognized and
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valid, regardless of the <link linkend="ini.short-open-tag">short_open_tag</link> setting.
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</para>
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</note>
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</para>
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</sect1>
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<sect1 xml:id="language.basic-syntax.instruction-separation">
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<title>Instruction separation</title>
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<para>
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As in C or Perl, PHP requires instructions to be terminated
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with a semicolon at the end of each statement. The closing tag
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of a block of PHP code automatically implies a semicolon; you
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do not need to have a semicolon terminating the last line of a
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PHP block. The closing tag for the block will include the immediately
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trailing newline if one is present.
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Examples of entering and exiting the PHP parser:
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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or <literal># ... ?></literal> WILL be printed:
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?> breaks out of PHP mode and returns to HTML mode, and
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<literal>//</literal> or <literal>#</literal> cannot influence that.
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If the <link linkend="ini.asp-tags">asp_tags</link> configuration directive
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is enabled, it behaves the same with <literal>// %></literal> and
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<literal># %></literal>.
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However, the <literal></script></literal> tag doesn't break out of PHP mode in
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a one-line comment.
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</simpara>
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<para>
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<informalexample>
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