structures in cell arrays

[John W. Eaton]

On 24-Sep-2003, Paul Griffiths <address@hidden> wrote:

| I have seen that a cell array element can be a structure. (See:
| 
http://www.octave.org/octave-lists/archive/octave-maintainers.2002/msg00012.html)
| 
| The example given is:
| octave:1> X{2,2}.bar(2).foo(2:3,2:3) = rand(2)
| 
| But I get the following error message when I try this statement:
| error: matrix cannot be indexed with .
| error: assignment failed, or no method for `<unknown type> = matrix'
| error: evaluating assignment expression near line 1, column 28
| octave:1> 
| 
| I have tried this on versions 2.1.44 and 2.1.50. I don't even need
| structure arrays. It would be sufficient if I could assign X{2,2}.a = 1. 

| Is there a patch? I also wish to load and save cell arrays with structures.
| If need be, I would consider contributing code to get this to work.

I think load/save should work if you use the HDF5 or Matlab formats.

Please try the following patch to fix the indexing problem.

Thanks,

jwe


src/ChangeLog

2003-09-24  John W. Eaton  <address@hidden>

        * ov-cell.cc (octave_cell::subsasgn): Also attempt empty
        conversion after extracting single element from cell array to
        allow things like x{i}.elt = rhs to work.


Index: src/ov-cell.cc
===================================================================
RCS file: /usr/local/cvsroot/octave/src/ov-cell.cc,v
retrieving revision 1.23
diff -u -r1.23 ov-cell.cc
--- src/ov-cell.cc      19 Sep 2003 21:41:21 -0000      1.23
+++ src/ov-cell.cc      24 Sep 2003 17:09:02 -0000
@@ -158,7 +158,11 @@
 
                    tmp.make_unique ();
 
-                   t_rhs = tmp.subsasgn (type.substr (1), next_idx, rhs);
+                   if (! tmp.is_defined () || tmp.is_empty ())
+                     tmp = octave_value::empty_conv (type.substr (1), rhs);
+
+                   if (! error_state)
+                     t_rhs = tmp.subsasgn (type.substr (1), next_idx, rhs);
                  }
              }
          }




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