Is it standard to use “Defined Constant as a prefix for a function name” or a “Variable Function” in PHP?

Question

This is the PHP Code:

define( 'FN_PREFIX', 'prefix_' );

${ FN_PREFIX . 'function_name' } = function( $string ) {
    echo $string;
};

$prefix_function_name( 'This is Working!!!' );

The Result:

This is Working!!!

Answer 1

No...! This is not at all standard .You have classes and methods with access specifiers and return types (PHP 7) to serve the purpose. Closure has different purpose.