How to change object's property in getter function of dependent variable ?

Hello everyone,

Let's say we have a class which has "prop" as property and "depProp" is "Dependent" property. Moreover, it will have getter function to calculate "depProp". The class definition would be like :

classdef Program
    properties 
        prop = 200;  
        
    end
    properties (Dependent)
        depProp
    end
    methods 
        function val = get.depProp(obj)
            val = prop*rand;
            if val>100
                obj.prop = 100; % gives an error 
            end
        end
    end
end

However, MATLAB gives an error because get.depProp function does not return "obj" as output so it cannot change the property of object. I know why it is happenning (it is value class and the object must be returned). I do not want to switch to handle class. So how can I change the object's property in the getter function of dependent variable. Inefficient solutions are also welcome.

Thank you in advance,

[Matt J]

However, MATLAB gives an error because get.depProp function does not return "obj" as output so it cannot change the property of object.

Matlab wouldn't give you an error message because of that. More likely, you are getting an error message because this line,

val = prop*rand;

should be,

val = obj.prop*rand;

Answer 1

[Matt J]

You could switch to a regular method,

classdef Program
    properties 
        prop = 200;  
        
    end

    methods 
        function [val,obj] = depProp(obj)
            val = obj.prop*rand;
            if val>100
                obj.prop = 100;
            end
        end
    end
end

Answer 2

[Matt J]

Another solution (far less recommendable, IMO) would be to hold the property data in a handle object of a different class. This would avoid turning Program into a handle class of its own.

classdef myclass<handle
    properties 
        data = 200;      
    end
end

classdef Program
    properties (Hidden,Access=private)
        prop_ = myclass;  
        
    end
    properties (Dependent)
        prop
        depProp
    end
    methods 
        function val=get.prop(obj)
            val=obj.prop_.data;
        end
        function obj=set.prop(obj,val)
            obj.prop_.data=val;
        end
        
        function val = get.depProp(obj)
            val = obj.prop*rand;
            if val>100
                obj.prop = 100; 
            end
        end
    end
end