// NaN is nil-like:
x := 0./0.
say "0./0. is $x"
if x
    say "$x is truthy"
else
    say "$x is falsey"

// if x == nil
//     say "$x is nil"
// else
//     say "$x is not nil"

if x == x
    say "$x is equal to itself"
else
    say "$x is not equal to itself"