doc-en/language/control-structures/alternative-syntax.xml at 353f61022362fbef1e43074c7d0b1d1830306407 · php/doc-en · GitHub

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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
$a = 5;
if ($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
$a = 5;
if ($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
$foo = 1;
switch ($foo): ?>
    <?php case 1: ?>
    Foo is 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>?&gt;</literal> and hence nothing is output between the
   <literal>switch</literal> and <literal>case</literal>:
  </para>
  <informalexample>
   <programlisting role="php">
<![CDATA[
<?php
$foo = 1;
switch ($foo): ?>
<?php case 1: ?>
    Foo is 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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