How to declare a null-able variable? Is “var {var_ref_name}?;” valid declaration?
var {var_ref_name}: type?;
the type must be specifed if the variable will be null-albe.
How to declare and initilize variable at in a single line?
for mutable variables:
var {var_ref_name} = value
for immutable variables:
val {var_ref_name}: type = value
or
val {var_ref_name} = value