Create a user-defined function that can be called by $callFunction or $functionName
$function[Function name;Param 1 (optional);Param 2...(optional)]
$function[printHello;name] Hello $name $endFunction
Call the function, using $callFunction
Call the function, using $printHello
Code inside the function is isolated from outside, which means changing of variables, arrays, random,...won't effect the outside.
you can access outside temporary variables (assigned by $let) but you can't change them.
A function name can't start with number, and must be within [A-Z or a-z or _ or 0-9] for short format ($functionName) but if you are using $callFunction to call the function, any name is valid