Yes, Octave should iterate over all "array" objects (numeric, cell, struct, class object) in a consistent way.  It's made a little bit more complex in Octave because we have "octave_value" objects that are containers for the other things instead of just having the octave_value object contain the dimensions and data directly as I assume Matlab does with the mxArray thing.

interesting. octave has always been able to iterate over a char array, since that's handled the same as a numeric array:

>> for idx = "abcd", idx, endfor
idx = a
idx = b
idx = c
idx = d

similar for cell arrays, and structs.  At first glance I was assuming this is a unique feature of "new" string objects.  But a quick test shows matlab can iterate over other object types as well.

trying a generic class object:

classdef myclass
  properties
    prop;
  end
  methods
    function obj = myclass(val)
      obj.prop = val;
    end
    function val = myprop(obj)
      val =[obj.prop];
    end
  end
end

you can step through the object array in matlab but not octave:

matlab 2022a:

a(1) = myclass(1);
a(2) = myclass(2);

for idx = a, idx, end

idx =
  myclass with properties:
    prop: 1

idx =
  myclass with properties:
    prop: 2

trying the same in octave 8.0.0 (hg id: 8b75954a4670)

>> for idx = a, idx, end
error: invalid type in for loop expression near line 1, column 1

based on the error message i don't think this is just related to bug #47755, as octave still doesn't consistently handle classdef object arrays in the first place.

I came across this from one of the examples here that is iterating over a string array:
https://blogs.mathworks.com/matlab/2022/09/15/an-introduction-to-dictionaries-associative-arrays-in-matlab/

for word = words'

It seems that it is not possible to iterate over the elements of a object array in a for-loop:

>> for i = obj
  i
endfor
error: invalid type in for loop expression near line 1, column 1