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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<sect1 xml:id="control-structures.alternative-syntax" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<title>Alternative syntax for control structures</title>
<?phpdoc print-version-for="control-structures.alternative-syntax"?>
<para>
PHP offers an alternative syntax for some of its control
structures; namely, <literal>if</literal>,
<literal>while</literal>, <literal>for</literal>,
<literal>foreach</literal>, and <literal>switch</literal>.
In each case, the basic form of the alternate syntax is to change
the opening brace to a colon (:) and the closing brace to
<literal>endif;</literal>, <literal>endwhile;</literal>,
<literal>endfor;</literal>, <literal>endforeach;</literal>, or
<literal>endswitch;</literal>, respectively.
<informalexample>
<programlisting role="php">
<![CDATA[
<?php if ($a == 5): ?>
A is equal to 5
<?php endif; ?>
]]>
</programlisting>
</informalexample>
</para>
<simpara>
In the above example, the HTML block "A is equal to 5" is nested within an
<literal>if</literal> statement written in the alternative syntax. The
HTML block would be displayed only if <varname>$a</varname> is equal to 5.
</simpara>
<para>
The alternative syntax applies to <literal>else</literal> and
<literal>elseif</literal> as well. The following is an
<literal>if</literal> structure with <literal>elseif</literal> and
<literal>else</literal> in the alternative format:
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
if ($a == 5):
echo "a equals 5";
echo "...";
elseif ($a == 6):
echo "a equals 6";
echo "!!!";
else:
echo "a is neither 5 nor 6";
endif;
?>
]]>
</programlisting>
</informalexample>
</para>
<note>
<para>
Mixing syntaxes in the same control block is not supported.
</para>
</note>
<warning>
<para>
Any output (including whitespace) between a <literal>switch</literal>
statement and the first <literal>case</literal> will result in a syntax
error. For example, this is invalid:
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php switch ($foo): ?>
<?php case 1: ?>
...
<?php endswitch; ?>
]]>
</programlisting>
</informalexample>
<para>
Whereas this is valid, as the trailing newline after the
<literal>switch</literal> statement is considered part of the closing
<literal>?></literal> and hence nothing is output between the
<literal>switch</literal> and <literal>case</literal>:
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php switch ($foo): ?>
<?php case 1: ?>
...
<?php endswitch; ?>
]]>
</programlisting>
</informalexample>
</warning>
<para>
See also <link linkend="control-structures.while">while</link>,
<link linkend="control-structures.for">for</link>, and <link
linkend="control-structures.if">if</link> for further examples.
</para>
</sect1>
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