Meaning of Matlab Notation: xx@yy

Question

I'm having trouble understanding the following code snippet. The simple call looks like this, without any assignment or else:

expression1@expression2;

expression2 is referring to a self defined handle class.

I've looked into handles but couldn't figure out what the given calling structure does, from the normal examples @(x) x^2; or f = @sin;and couldn't find similar examples online.

Any help on what the notation might do is appreciated.

Answer 1

Without context it's hard to say for sure, but this looks like a subclass calling the superclass method (usually before additional functionality in the subclass implementation)...

See the docs here.

Example from the linked docs:

classdef Sub < Super
   methods
      function foo(obj)
         % preprocessing steps
          ...
         foo@Super(obj);
         % postprocessing steps
          ...
      end
   end
end

In this case, the foo function is defined in the Super class, implemented in the subclass Sub, and extended (with preprocessing and postprocessing). The foo@Super(obj) notation calls the superclass method from the subclass.

Note that this is analogous to SuperObj.foo(obj), except you don't have an instantiated object (SuperObj) of class Super to make this call. And since you're extending / overriding the superclass version of the function, you can't just call obj.foo() as you would if the subclass implementation was identical - that's the function you're already in! Hence the need for this different notation.