PHP/function variable: Difference between revisions
from HTYP, the free directory anyone can edit if they can prove to me that they're not a spambot
< PHP
Created page with "==About== A variable can store a reference to a function. The thing that isn't explained very well in the documentation is that this just consists of naming the function in a..." |
No edit summary |
||
| Line 1: | Line 1: | ||
==About== | ==About== | ||
A variable can store a reference to a function. The thing that isn't explained very well in the documentation is that | A variable can store a reference to a function, which can then be called from the variable. | ||
===Named Functions/Methods=== | |||
The thing that isn't explained very well in the documentation is that if you want to assign a ''predefined'' function to a variable, you just use a string which is a callable/accessible form of the function. | |||
<syntaxhighlight lang=php> | <syntaxhighlight lang=php> | ||
function Example1() { echo "Example1 was called!\n"; } | function Example1() { echo "Example1 was called!\n"; } | ||
| Line 19: | Line 21: | ||
$fEx2(); // prints "Test1 was called!" | $fEx2(); // prints "Test1 was called!" | ||
</syntaxhighlight> | </syntaxhighlight> | ||
The variable can be used to call the function in exactly the same way as if it had been assigned an anonymous function. | |||
===Anonymous Functions=== | |||
<syntaxhighlight lang=php> | |||
$fEx3 = function() { echo "Anonymous function was called!\n"; }; | |||
$fEx3(); // prints "Anonymous function was called!" | |||
</syntaxhighlight> | |||
Unlike with predefined functions, however, the type for the variable is '''Callable''' rather than '''string'''. | |||
==Documentation== | ==Documentation== | ||
* [https://www.php.net/manual/en/langref.php Language Reference]: | * [https://www.php.net/manual/en/langref.php Language Reference]: | ||
Revision as of 17:38, 10 April 2022
About
A variable can store a reference to a function, which can then be called from the variable.
Named Functions/Methods
The thing that isn't explained very well in the documentation is that if you want to assign a predefined function to a variable, you just use a string which is a callable/accessible form of the function.
function Example1() { echo "Example1 was called!\n"; }
#$fEx1 = Example1; // does not work; sees "Example1" as a constant
$fEx1 = 'Example1';
$fEx1(); // prints "Example1 was called!"
class cExample2 {
static public function Test1() { echo "Test1 was called!\n"; }
}
#$fEx2 = cExample2::Test1; // does not work; sees "Test1" as a class constant
$fEx2 = 'cExample2::Test1';
$fEx2(); // prints "Test1 was called!"
The variable can be used to call the function in exactly the same way as if it had been assigned an anonymous function.
Anonymous Functions
$fEx3 = function() { echo "Anonymous function was called!\n"; };
$fEx3(); // prints "Anonymous function was called!"
Unlike with predefined functions, however, the type for the variable is Callable rather than string.
