A.1.4 Cell Arrays in Oct-Files

Octave's cell type is equally accessible within oct-files. A cell array is just an array of octave_values, and so each element of the cell array can then be treated just like any other octave_value. A simple example is

     #include <octave/oct.h>
     #include <octave/Cell.h>
     
     DEFUN_DLD (celldemo, args, , "Cell Demo")
     {
       octave_value_list retval;
       int nargin = args.length ();
     
       if (nargin != 1)
         print_usage ();
       else
         {
           Cell c = args (0).cell_value ();
           if (! error_state)
             for (octave_idx_type i = 0; i < c.nelem (); i++)
               retval(i) = c.elem (i);
         }
     
       return retval;
     }

Note that cell arrays are used less often in standard oct-files and so the Cell.h header file must be explicitly included. The rest of this example extracts the octave_values one by one from the cell array and returns be as individual return arguments. For example consider

     [b1, b2, b3] = celldemo ({1, [1, 2], "test"})
     ⇒
     b1 =  1
     b2 =
     
        1   2
     
     b3 = test