require subclasses to support the same number of input and output arguments as the abstract method of their super class

in the documentation about abstract methods in an abstract class it is mentioned that:

• Concrete subclasses are not required to support the same number of input and output arguments and do not need to use the same argument names. However, subclasses generally use the same signature when implementing their version of the method.

what I want is exactly the opposite, i.e. I want Concrete subclasses are required to support the same number of input and output arguments and otherwise I get an error. How is it possible?

Answer 1

[Matt J]

In the base class constructor, you can check the function signature, like in this example:

classdef myclass

    methods
        function obj=myclass()


            ml=getfield(metaclass(obj),'MethodList');

            meth=ml({ml.Name}=="myMethod");

          assert(isequal(numel(meth.InputNames),4) && ...
                 isequal(numel(meth.OutputNames),2),...
                 "myMethod has incorrect signature in subclass "+class(obj))

        end
    end

    methods(Abstract)
        [out1,out2]=myMethod(obj, in1, in2, in3)
    end

    
end

[Masa]

this could be achieved easily, if there was an attribute for example restrictInOuts for methods:

abstract methods with restricted number of inputs and outputs:

methods(Abstract, restrictInOuts=true)
    [out1,out2]=myMethod(obj, in1, in2, in3)
end

abstract methods with any arbitrary number of inputs and outputs:

methods(Abstract, restrictInOuts=false)
    myMethod(obj)
end

[Matt J]

You could ask them to implement it, but I doubt it's as easy as that. When the signature contains varargin or varargout, I imagine things get complicated.