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<?xml version="1.0" encoding="utf-8"?>
<refentry xml:id="backedenum.tryfrom" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<refnamediv>
<refname>BackedEnum::tryFrom</refname>
<refpurpose>Maps a scalar to an enum instance or null</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis role="BackedEnum">
<modifier>public</modifier> <modifier>static</modifier> <type class="union"><type>static</type><type>null</type></type><methodname>BackedEnum::tryFrom</methodname>
<methodparam><type class="union"><type>int</type><type>string</type></type><parameter>value</parameter></methodparam>
</methodsynopsis>
<para>
The <methodname>tryFrom</methodname> method translates a <type>string</type> or <type>int</type>
into the corresponding Enum case, if any. If there is no matching case defined, it will
return null.
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<variablelist>
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<para>
The scalar value to map to an enum case.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
A case instance of this enumeration, or <type>null</type> if not found.
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<example>
<title>Basic usage</title>
<para>
The following example illustrates how enum cases are returned.
</para>
<programlisting role="php">
<![CDATA[
<?php
enum Suit: string
{
case Hearts = 'H';
case Diamonds = 'D';
case Clubs = 'C';
case Spades = 'S';
}
$h = Suit::tryFrom('H');
var_dump($h);
$b = Suit::tryFrom('B') ?? Suit::Spades;
var_dump($b);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
enum(Suit::Hearts)
enum(Suit::Spades)
]]>
</screen>
</example>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><methodname>UnitEnum::cases</methodname></member>
<member><methodname>BackedEnum::from</methodname></member>
</simplelist>
</para>
</refsect1>
</refentry>
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