Is is possible to control the order of inherited class properties?

Consider two simple classes, where one inherits from the other:

First class:

classdef Example_Class_1 < handle 
    properties
        Property1
        Property2
    end
end

Second class:

classdef Example_Class_2 < Example_Class_1 
    properties
        Property3
    end
end

Now, if I create an Example_Class_2 object, its properties are listed as follows:

Example_Class_2

ans = 

  Example_Class_2 with properties:

    Property3: []
    Property1: []
    Property2: []

Is there some alternative syntax I can use when defining Example_Class_2, such that Property1 and Property 2 (the inherited properties) appear before Property3 when an Example_Class_2 object is created?

Answer 1

[Harry Dymond]

Following the advice of William Warriner, here is what can be done. Change Example_Class_2 as follows:

classdef Example_Class_2 < Example_Class_1 & matlab.mixin.CustomDisplay
    properties
        Property3
    end
    methods (Hidden)
        function value = properties( obj )
            propList = sort( builtin("properties", obj) );
            if nargout == 0
                disp(propList);
            else
                value = propList;
            end
        end
        function value = fieldnames( obj )
            value = sort( builtin( "fieldnames", obj ) );
        end
    end
    methods (Access = protected)
        function group = getPropertyGroups( obj )
            props = properties( obj );
            group = matlab.mixin.util.PropertyGroup( props );
        end
    end
end

Now, properties are listed in alphabetical order, both when displayed on the command line, and when returned as a cell array (with e.g. propList = properties(Example_Class_2))

Of course, you don't have to use sort() to re-order the property list in the properties method. In my case, I needed a different ordering and just used

propList = builtin("properties", obj);
propList = propList([<my custom indices order>]);

Answer 2

[Steven Lord]

Have your class inherit from matlab.mixin.CustomDisplay and override the getPropertyGroups method. See the "Customize Property Display" section on this documentation page for an example.

[Harry Dymond]

Hi Steven, thanks for the reply. Your answer appeared whilst I was working on mine!

Answer 3

[Ashwin]

Although there isn’t any explicit way by which the order of printing of the properties can be changed, you can attempt to overload the properties() function in order to print the properties of a required class in the order you require it. The below question does the same for dynamic properties, it could be of reference.

https://www.mathworks.com/matlabcentral/answers/9777-oop-dynamic-properties-ordering-is-very-strange

However, the process does seem rather tedious to reproduce.

[Harry Dymond]

Thanks for the speedy reply! Actually, the answer on that thread from William Warriner is very simple to implement - see my accepted answer.