How do I check if a variable is empty?

RouterOS Scripting
1

I’m writing a simple script and i’m a little stuck. I need to check if a variable is empty. How can I do that?

2

You could check variable length, something like:

:if ([:len $var] = 0) do={
  ... your code here
}
3

It seems to be working. Unfortunately it’s not exactly doing what I meant it to do. The same thing applies to my previous code…
Thanks anyway.