Overloading subsref and multiple outputs

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Daniel 2013-12-6

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/108854-overloading-subsref-and-multiple-outputs

I am able to overload subsref in my classes, but I have noticed some rather odd behavior. I have implemented a very simple class, which you can see below. It has a single property.

If I have an array of these objects, and I access that property, I get multiple outputs. In fact, I get one output for each element in my array, as expected.

When I place a break point in the subsref function to observer what is going on, I notice that nargout evaluates to the number of elements in my object array, again, as expected.

The first unexpected thing is that if I index into to object array, I no longer get multiple outputs, that is, unless I specifically ask for multiple outputs.

The second unexpected thing I noticed, is that when I place a break point in the subsref function, nargout evaluates to zero, unless I specify before hand how many outputs I want.

This behavior has several less than ideal implications for me, which are not really related to the this question.

Is there any way to get the same behavior for the indexed object array as for the un-indexed array?

Any ideas are more than welcome.

Thanks.

 >> obj = [MyClass MyClass MyClass]; % Now I have a 1x3 object array
 >> obj.prop
 ans = 
       0
 ans = 
       0
 ans = 
       0
 >> obj(1:3).prop
 ans = 
       0
 >> [a,b,c] = obj(1:3).prop
 a = 
     0
 b = 
     0
 c = 
     0
 >> x = [obj.prop]
 x = 
     0 0 0
 >> y = [obj(1:3).prop]
 y = 
     0
 >>
-------------------------------------------------------------------------------------
   classdef MyClass < handle
       properties 
         prop = 0;
       end
       methods
          function varargout = subsref(this,S)
            [varargout{1:nargout}] = builtin('subsref',this,S);
          end
       end
   end