<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->

<refentry xml:id="dateperiod.construct" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>DatePeriod::__construct</refname>
  <refpurpose>Creates a new DatePeriod object</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <constructorsynopsis role="DatePeriod">
   <modifier>public</modifier> <methodname>DatePeriod::__construct</methodname>
   <methodparam><type>DateTimeInterface</type><parameter>start</parameter></methodparam>
   <methodparam><type>DateInterval</type><parameter>interval</parameter></methodparam>
   <methodparam><type>int</type><parameter>recurrences</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>options</parameter><initializer>0</initializer></methodparam>
  </constructorsynopsis>
  <constructorsynopsis role="DatePeriod">
   <modifier>public</modifier> <methodname>DatePeriod::__construct</methodname>
   <methodparam><type>DateTimeInterface</type><parameter>start</parameter></methodparam>
   <methodparam><type>DateInterval</type><parameter>interval</parameter></methodparam>
   <methodparam><type>DateTimeInterface</type><parameter>end</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>options</parameter><initializer>0</initializer></methodparam>
  </constructorsynopsis>
  <warning>
   <constructorsynopsis role="DatePeriod">
    <modifier>public</modifier> <methodname>DatePeriod::__construct</methodname>
    <methodparam><type>string</type><parameter>isostr</parameter></methodparam>
    <methodparam choice="opt"><type>int</type><parameter>options</parameter><initializer>0</initializer></methodparam>
   </constructorsynopsis>
   <simpara>
    This variant of the constructor has been deprecated, use
    <methodname>DatePeriod::createFromISO8601String</methodname> instead.
   </simpara>
  </warning>
  <para>
   Creates a new DatePeriod object.
  </para>
  <para>
   <classname>DatePeriod</classname> objects can be used as an iterator to
   generate a number of <classname>DateTimeImmutable</classname> or
   <classname>DateTime</classname> object from a <parameter>start</parameter>
   date, a <parameter>interval</parameter>, and an <parameter>end</parameter>
   date or the number of <parameter>recurrences</parameter>.
  </para>
  <para>
   The class of returned objects is equivalent to the
   <classname>DateTimeImmutable</classname> or <classname>DateTime</classname>
   ancestor class of the <parameter>start</parameter> object.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>start</parameter></term>
     <listitem>
      <para>
       The start date of the period. Included by default in the result set.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>interval</parameter></term>
     <listitem>
      <para>
       The interval between recurrences within the period.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>recurrences</parameter></term>
     <listitem>
      <para>
       The number of recurrences. The number of returned results is
       one higher than this, as the start date is included in the result set
       by default. Must be greater than <literal>0</literal>.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>end</parameter></term>
     <listitem>
      <para>
       The end date of the period. Excluded by default from the result set.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>isostr</parameter></term>
     <listitem>
      <para>
       A subset of the <link
       xlink:href="&url.iso-8601.repeating_intervals;">ISO 8601 repeating
       interval specification</link>.
      </para>
      <para>
       Examples of some ISO 8601 interval specification features that PHP does
       not support are:
      </para>
      <orderedlist>
       <listitem>
        <simpara>
         zero occurrences (<literal>R0/</literal>)
        </simpara>
       </listitem>
       <listitem>
        <simpara>
         time offsets other than UTC (<literal>Z</literal>), such as <literal>+02:00</literal>.
        </simpara>
       </listitem>
      </orderedlist>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>options</parameter></term>
     <listitem>
      <para>
       A bit field which can be used to control certain behaviour with start-
       and end- dates.
      </para>
      <para>
       With <constant>DatePeriod::EXCLUDE_START_DATE</constant> you
       exclude the start date from the set of recurring dates within the
       period.
      </para>
      <para>
       With <constant>DatePeriod::INCLUDE_END_DATE</constant> you
       include the end date in the set of recurring dates within the
       period.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  <para>
   Throws an <classname>DateMalformedPeriodStringException</classname> when
   the <parameter>isostr</parameter> cannot be parsed as a valid ISO 8601
   period. Prior to PHP 8.3, this was
   <exceptionname>Exception</exceptionname>.
  </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>8.3.0</entry>
       <entry>
        Now throws
        <exceptionname>DateMalformedPeriodStringException</exceptionname>
        instead of <exceptionname>Exception</exceptionname>.
       </entry>
      </row>
      <row>
       <entry>8.2.0</entry>
       <entry>
        The <constant>DatePeriod::INCLUDE_END_DATE</constant> constant has been added.
       </entry>
      </row>
      <row>
       <entry>7.2.19, 7.3.6, 7.4.0</entry>
       <entry>
        <parameter>recurrences</parameter> must be greater than <literal>0</literal> now.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>DatePeriod example</title>
    <programlisting role="php">
<![CDATA[
<?php
$start = new DateTime('2012-07-01');
$interval = new DateInterval('P7D');
$end = new DateTime('2012-07-31');
$recurrences = 4;
$iso = 'R4/2012-07-01T00:00:00Z/P7D';

// All of these periods are equivalent.
$period = new DatePeriod($start, $interval, $recurrences);
$period = new DatePeriod($start, $interval, $end);
$period = new DatePeriod($iso);

// By iterating over the DatePeriod object, all of the
// recurring dates within that period are printed.
foreach ($period as $date) {
    echo $date->format('Y-m-d')."\n";
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
2012-07-01
2012-07-08
2012-07-15
2012-07-22
2012-07-29
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title>DatePeriod example with <constant>DatePeriod::EXCLUDE_START_DATE</constant></title>
    <programlisting role="php">
<![CDATA[
<?php
$start = new DateTime('2012-07-01');
$interval = new DateInterval('P7D');
$end = new DateTime('2012-07-31');

$period = new DatePeriod($start, $interval, $end,
                         DatePeriod::EXCLUDE_START_DATE);

// By iterating over the DatePeriod object, all of the
// recurring dates within that period are printed.
// Note that, in this case, 2012-07-01 is not printed.
foreach ($period as $date) {
    echo $date->format('Y-m-d')."\n";
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
2012-07-08
2012-07-15
2012-07-22
2012-07-29
]]>
    </screen>
   </example>
  </para>
  <para>
   <example>
    <title>DatePeriod example showing all last Thursdays in a year</title>
    <programlisting role="php">
<![CDATA[
<?php
$begin = new DateTime('2021-12-31');
$end = new DateTime('2022-12-31 23:59:59');

$interval = DateInterval::createFromDateString('last thursday of next month');
$period = new DatePeriod($begin, $interval, $end, DatePeriod::EXCLUDE_START_DATE);

foreach ($period as $dt) {
    echo $dt->format('l Y-m-d'), "\n";
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
Thursday 2022-01-27
Thursday 2022-02-24
Thursday 2022-03-31
Thursday 2022-04-28
Thursday 2022-05-26
Thursday 2022-06-30
Thursday 2022-07-28
Thursday 2022-08-25
Thursday 2022-09-29
Thursday 2022-10-27
Thursday 2022-11-24
Thursday 2022-12-29
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <simpara>
   Unbound numbers of repetitions as specified by ISO 8601 section 4.5
   "Recurring time interval" are not supported, i.e. neither passing
   <literal>"R/..."</literal> as <parameter>isostr</parameter> nor passing
   &null; as <parameter>end</parameter> would work.
  </simpara>
 </refsect1>

</refentry>

<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->