How to detect the 'end' directive in subsref?

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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?

Accepted Answer

Steven Lord
Steven Lord on 30 Jan 2020
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.
  1 Comment
Alex Kashuba
Alex Kashuba on 30 Jan 2020
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!

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