How to detect the 'end' directive in subsref?

Hi all!

I am trying to reimplement the indexing of the object. Let us take as an example this primitive class that return the substript

classdef buffer
    function value = subsref(obj, S)
        value = S(1).subs{1};
    end
end

Let's create object

buf=buffer()

Then buf(7) returns 7. buf(3:7) returns [3 4 5 6 7]. All good so far. Then buf(:) returns char ':'. Ok, can process that. Now comes the funny part:

buf(end) returns 1

buf(end+1) returns 2

buf(1:end) returns 1

buf(2:end) returns []

Question: is there a workaround so that 'end' is not always equivalent of 1, but I would be able to add my own implementation?

Answer 1

[Steven Lord]

Overload the end method for your class as described on this documentation page.

The reason end was always taking the value 1 is probably because your object is a scalar (size [1 1]) that internally contains an array. Consider overloading size to return the size of that internal array if appropriate.

[Alex Kashuba]

Yep, precisely what I needed, thanks!

P.S. No, overloading 'size' won't work for me, I'm making a fifo with random access, so internal array will partially empty, and I will have to implement the indexing separately. But overloading 'end' should do. Thanks!