What is the difference of public-read and public-read protected

Question

I have noticed that the access of some variables in API document is public-read protected. I tried the following code. They seem all the same.
class FatherClass{
public-read var a;
public-read protected var b;
init{
    a=1;
    println(a);
    b=1;
    println(b);
class SubClass extends FatherClass{
    init{
        a=4;
        println(a);
        b=4;
        println(b);
var subClass=SubClass{};

Answer 1

As you see in my code, subclass can write the variable with either public-read and public-read protected. What write access do the public-read protected widen? That's because your subclass is in the same script as the variable. Move the subclass to a separate script and it would not be able to write when the access is public-read.
"public-read" = any code can read, code in the same script can write.
"public-read protected" = any code can read, code in the same script, in the same package or in a subclass can write.