How to execute a variable function that has a default input - laravel-5

Question

I have a scheduler something like
$schedule->command('foo')
->weekdays()
->hourly()
->timezone('America/Chicago')
->between('8:00', '17:00');
I would like to store ->between('8:00', '17:00'); in my database so that I can always change it. Later on for example I can use rather ->at('02:00') ( just example ).
I know that with PHP7 we can use variable functions better than every something like
http://php.net/manual/en/functions.variable-functions.php
<?php
function sound_dog()() { return 'woof'; }
function sound_cow()() { return 'moo'; }
$animal = 'cow';
print ('sound_' . $animal)();
But when I want to have an default input inside ('anything at all') it doesn't work. All examples assumes that there is no default input.
How can I make a variable function that has input inside itself?

Answer 1

If I've got you correctly, your question consists of two parts:
How to use default arguments values with PHP variable functions
How to make flexible scheme for Laravel scheduler setup
and
Regarding your first question - here is an example of default arguments values for variable functions:
function sound_cow(string $sound = 'moo') { return $sound; }
$animal = 'cow';
print ('sound_' . $animal)();
print ('sound_' . $animal)('moowoof');
Regarding your second question - I believe that is not a good idea at all to store code chunks and generate your script from it. At first it looks like a clever trick, but this functional quickly becomes complicated and fragile as your program gets bigger. It is vulnerable as it could provide an opportunity to launch malicious code injected into your database. It is also difficult to refactor when you are going to rewrite it for another PHP framework for example (or even port it to another programming language) because depends on specific scheduler implementation.
If you need so flexible scheduler IMHO it is better to implement your own configurable abstraction layer above Laravel's scheduler with functional that you need.
P.S. BTW your code example has a mistake - redundant brackets in functions definitions.