File: var-export.xml

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<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.13 $ -->
<!-- splitted from ./en/functions/var.xml, last change in rev 1.6 -->
<refentry id="function.var-export">
 <refnamediv>
  <refname>var_export</refname>
  <refpurpose>Outputs or returns a parsable string representation of a variable</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>mixed</type><methodname>var_export</methodname>
   <methodparam><type>mixed</type><parameter>expression</parameter></methodparam>
   <methodparam choice="opt"><type>bool</type><parameter>return</parameter></methodparam>
  </methodsynopsis>
  <simpara>
   <function>var_export</function> gets structured information about the 
   given variable. It is similar to <function>var_dump</function>
   with one exception: the returned representation is valid PHP code.
  </simpara>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>expression</parameter></term>
     <listitem>
      <para>
       The variable you want to export.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>return</parameter></term>
     <listitem>
      <para>
       If used and set to &true;, <function>var_export</function> will return
       the variable representation instead of outputing it.
      </para>
      &note.uses-ob;
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the variable representation when the <parameter>return</parameter> 
   parameter is used and evaluates to &true;. Otherwise, this function will
   return &null;.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>5.1.0</entry>
       <entry>
        Possibility to export classes and arrays containing classes using the
        <link linkend="language.oop5.magic.set-state">__set_state</link> magic
        method.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>
 
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>var_export</function> Examples</title>
    <programlisting role="php">
<![CDATA[
<?php
$a = array (1, 2, array ("a", "b", "c"));
var_export($a);
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
array (
  0 => 1,
  1 => 2,
  2 => 
  array (
    0 => 'a',
    1 => 'b',
    2 => 'c',
  ),
)
]]>
    </screen>
    <programlisting role="php">
<![CDATA[
<?php

$b = 3.1;
$v = var_export($b, true);
echo $v;

?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
3.1
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title>Exporting classes since PHP 5.1.0</title>
    <programlisting role="php">
<![CDATA[
<?php
class A { public $var; }
$a = new A;
$a->var = 5;
var_export($a);
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
A::__set_state(array(
   'var' => 5,
))
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title>Using <link linkend="language.oop5.magic.set-state">__set_state</link> (since PHP 5.1.0)</title>
    <programlisting role="php">
<![CDATA[
<?php
class A
{
    public $var1;
    public $var2;

    public static function __set_state($an_array)
    {
        $obj = new A;
        $obj->var1 = $an_array['var1'];
        $obj->var2 = $an_array['var2'];
        return $obj;
    }
}

$a = new A;
$a->var1 = 5;
$a->var2 = 'foo';

eval('$b = ' . var_export($a, true) . ';'); // $b = A::__set_state(array(
                                            //    'var1' => 5,
                                            //    'var2' => 'foo',
                                            // ));
var_dump($b);
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
object(A)#2 (2) {
  ["var1"]=>
  int(5)
  ["var2"]=>
  string(3) "foo"
}
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    Variables of type <type>resource</type> couldn't be exported by this
    function.
   </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>var_dump</function></member>
    <member><function>print_r</function></member>
   </simplelist>
  </para>  
 </refsect1>
</refentry>

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