value classes - do you use them? I must be doing something wrong...

So I can't really recall ever creating a value class, all mine seem to be handle classes. Is that the same as your experience? Unless I'm completely missing something, using value classes seems to be painful, because you always have to do two steps like this:

foo = MyValueClass(5); % sets a property 'val'
foo = foo.double();
plot(foo.val);

With a handle class, I'd just do this:

foo = MyHandleClass(5);
plot(foo.double()); % double returns the new obj.val directly.

Am I completely out to lunch with this understanding of value classes?

As an aside, sometimes it seems like it would be nice to have the above syntax of a handle class, but be able to make independent copies of a given object like a value class... Anyone else think so?

Thanks for your thoughts, Eric

Answer 1

[Andrew Newell]

I have no idea what your method double does or what your class constructor does with the input, so I'll create a trivial example where you could do your plot in two commands:

classdef MyValueClass

    properties
        val
    end

    methods
        function obj = MyValueClass(val)
            obj.val = val;
        end
    end

end

Now for an example of its use:

foo = MyValueClass(0:1);
plot(foo.val)

See Comparing Handle and Value Classes. For much of the work I do, value classes are preferable.