It's probably not that you're overthinking it, just that you haven't encountered !
in programming languages before. It's pretty straightforward, though -- here's a quick explanation.
If you want to do something based on a condition, you use an if
statement, right? For example,
if has('relativenumber')
echo "Your Vim has the relative number feature!"
endif
If you want to do something if that condition is not true, you put a !
before your condition. (this is called "negating" a logical condition)
if !has('relativenumber')
echo "Your Vim does NOT have the relative number feature."
endif
You can use that in other case too. Take this, for example:
if x > 3
echo "x is greater than three"
endif
You have to include parentheses to negate it though. (Order of operations!)
if !(x > 3)
echo "x is less than or equal to three"
endif
This is equivalent to
if x <= 3
echo "x is less than or equal to three"
endif