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Interface, children, callable, trait

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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@324171 c90b9560-bf6c-de11-be94-00142212c4b1
This commit is contained in:
Jakub Vrana 2012-03-13 01:39:06 +00:00
parent ec6de8a539
commit 725924e665
1 changed files with 36 additions and 9 deletions
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45
language/oop5/typehinting.xml
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@ -3,13 +3,25 @@
<sect1 xml:id="language.oop5.typehinting" xmlns="http://docbook.org/ns/docbook">
<title>Type Hinting</title>
<para>
PHP 5 introduces Type Hinting. Functions are now able to force parameters
PHP 5 introduces type hinting. Functions are now able to force parameters
to be objects (by specifying the name of the class in the function
prototype) or arrays (since PHP 5.1). However, if <type>NULL</type> is used
prototype), interfaces, arrays (since PHP 5.1) or <type>callable</type>
(since PHP 5.4). However, if <type>NULL</type> is used
as the default parameter value, it will be allowed as an argument for any
later call.
</para>
<para>
If class or interface is specified as type hint then all its children or
implementations are allowed too.
</para>
<para>
Type hints can not be used with scalar types such as <type>int</type> or
<type>string</type>.
<link linkend="language.oop5.traits">Traits</link> are not allowed either.
</para>
<example>
<title>Type Hinting examples</title>
<programlisting role="php">
@ -36,6 +48,20 @@ class MyClass
public function test_array(array $input_array) {
print_r($input_array);
}
/**
* First parameter must be iterator
*/
public function test_interface(Traversable $iterator) {
echo get_class($iterator);
}
/**
* First parameter must be callable
*/
public function test_callable(callable $callback, $data) {
call_user_func($callback, $data);
}
}
// Another example class
@ -73,6 +99,12 @@ $myclass->test_array('a string');
// Works: Prints the array
$myclass->test_array(array('a', 'b', 'c'));
// Works: Prints ArrayObject
$myclass->test_interface(new ArrayObject(array()));
// Works: Prints int(1)
$myclass->test_callable('var_dump', 1);
?>
]]>
</programlisting>
@ -92,13 +124,13 @@ class MyClass {
*
* First parameter must be an object of type MyClass
*/
function MyFunction (MyClass $foo) {
function myFunction(MyClass $foo) {
echo $foo->var;
}
// Works
$myclass = new MyClass;
MyFunction($myclass);
myFunction($myclass);
?>
]]>
</programlisting>
@ -121,11 +153,6 @@ test(new stdClass);
]]>
</programlisting>
</example>
<para>
Type Hints can only be of the <type>object</type> and <type>array</type>
(since PHP 5.1) type. Traditional type hinting with <type>int</type> and
<type>string</type> isn't supported.
</para>
</sect1>
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