Custom Function names

Excuse me, does PHP support custom functions when declaring, the function name takes the form of a variable, how is it used?
I tried it.
function $a {}
$a = ' test ';
Test ();
?>
Prompt error.

Reply to discussion (solution)

You can't do that.
I can do this.

function Test () {} $a = ' test '; $a ();

You can't do that.
I can do this.

function Test () {} $a = ' test '; $a ();

The problem is I don't want this effect ...

The situation I encountered was that the function name might not be the same, but the contents of the function were the same, but for special reasons
When a function is declared, the function name is unknown and can only be determined until the actual call is made.

You can do this by class (__call)

1. Using eval

$a = ' test '; eval ("function $a () {echo ' function name is: '. __function__;}"); Test ();

2. Using the Magic method of class __call

Class foo{public    function __call ($name, $param) {        if ($name = = ' Test ') {            echo ' Test ';        } else{            Echo ' name not exists ';}}    } $obj = new Foo (), $a = ' test ', $obj-$a ();

