SunshinePHP Developer Conference 2015

Pseudo tipos y variables usadas en esta documentación

mixed

mixed indica que un parámetro puede aceptar múltiples tipos (pero no necesariamente todos).

gettype(), por ejemplo, puede aceptar todos los tipos PHP, mientras que str_replace() sólo acepta strings y arrays.

number

number indica que un parámetro puede ser tanto un integer como un float.

Llamada de retorno

Los pseudo-tipos callback fueron usados en está documentación antes de que la sugerencia de tipo callable fuera introducida en PHP 5.4. Significan exactamente lo mismo.

void

void como un tipo de variable de retorno significa que el valor de retorno no es útil. void en una lista de parámetros significa que la función no acepta ningún parámetro.

...

$... en el prototipo de funciones significa and so on. Este nombre de variable se usa cuando una función puede tomar un número infinito de argumentos.

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User Contributed Notes 8 notes

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27
phpguy at lifetoward dot com
5 years ago
I noticed two important thing about putting callbacks into an arg list when calling a function:

1. The function to which the callback refers must be defined earlier in the source stream. So for example:

function main() {...; usort($array, 'sortfunction'); ... }
function sortfunction($a, $b){ return 0; }

Will NOT work, but this will:

function sortfunction($a, $b){ return 0; }
function main() {...; usort($array, 'sortfunction'); ... }

2. It's not really just a string. For example, this doesn't work:

usort($array, ($reverse?'reversesorter':'forwardsorter'));

I found these two discoveries quite counterintuitive.
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-1
michael dot martinek at gmail dot com
5 years ago
The documentation is a little confusing, and with the recent OO changes it adds a little more to the confusion.

I was curious whether you could pass an object through the user func, modify it in that callback and have the actual object updated or whether some cloning was going on behind the scenes.

<?php
   
class Test
   
{
        var
$sValue = 'abc';

        function
testing($objTest)
        {
           
$objTest->sValue = '123';
        }
    }

   
$obj = new Test();

   
call_user_func(array($obj, 'testing'), $obj);

   
var_dump($obj);

?>

This works as expected: The object is not cloned, and $sValue is properly set to '123'. With the OO changes in PHP 5, you don't need to do "function testing(&$objTest)" as it is already passed by reference.
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-4
Edward
7 years ago
To recap mr dot lilov at gmail dot com's comment: If you want to pass a function as an argument to another function, for example "array_map", do this:

regular functions:
<?
array_map
(intval, $array)
?>

static functions in a class:
<?
array_map
(array('MyClass', 'MyFunction'), $array)
?>

functions from an object:
<?
array_map
(array($this, 'MyFunction'), $array)
?>

I hope this clarifies things a little bit
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-6
sahid dot ferdjaoui at gmail dot com
5 years ago
An example with PHP 5.3 and lambda functions

<?php

  array_map
(function ($value) {
    return new
MyFormElement ($value);
  },
$_POST);

?>
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-12
mike@EastGhostCom
2 years ago
If you pass a string as the callback function (i.e., 2nd parm to preg_replace_callback()), then PHP will interpret it as a function's name in the current scope -- and Main::dada_cb is not a valid function name in any scope.

If you want to specify a static method of a class as the callback (i.e., "Main::dada_cb"), then you must pass as 2nd parm to preg_replace_callback:

array( 'Main', 'dada_cb')

And, if you want to use as a callback some method of an instantiated object (i.e., $object->dada_cb), then you must pass as the 2nd parm to preg_replace_callback:

array( $object, 'dada_cb' )
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-11
Hayley Watson
7 years ago
The mixed pseudotype is explained as meaning "multiple but not necessarily all" types, and the example of str_replace(mixed, mixed, mixed) is given where "mixed" means "string or array".
Keep in mind that this refers to the types of the function's arguments _after_ any type juggling.
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-19
liam at helios-sites dot com
3 years ago
Note that (e.g.) usort calls on static methods of classes in a namespace need to be laid out as follows:

usort($arr, array('\Namespace\ClassName', 'functionName'));
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-20
levi at alliancesoftware dot com dot au
7 years ago
Parent methods for callbacks should be called 'parent::method', so if you wish to call a non-static parent method via a callback, you should use a callback of
<?
// always works
$callback = array($this, 'parent::method')

// works but gives an error in PHP5 with E_STRICT if the parent method is not static
$callback array('parent', 'method');
?>
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