Re: cell-array display in class

[Oliver Heimlich]

On 27.04.2015 06:05, Oliver Heimlich wrote:
> On 26.04.2015 22:35, Colin Macdonald wrote:
> > Hi,
> >
> > I like how Octave displays cell arrays.  Is it possible to enable the
> > `[i,j] = ` display in my own class?  If so, how?  If not, I'll file a
> > bug to improve on the status quo shown below.
> >
> > Example: good:
> >
> > > >> C = {1 2; 3 4}
> > > C =
> > > {
> > >   [1,1] =  1
> > >   [2,1] =  3
> > >   [1,2] =  2
> > >   [2,2] =  4
> > > }
> >
> > Not so good:
> >
> > > >> pkg load symbolic
> > > >> pkg load interval
> > >
> > > >> C(2,1) = sym('x')
> > > C =
> > > {
> > >   [1,1] =  1
> > > (sym) x
> > >   [1,2] =  2
> > >   [2,2] =  4
> > > }
> > > >> C(2,2) = infsup(0,5)
> > > C =
> > > {
> > >   [1,1] =  1
> > > (sym) x
> > >   [1,2] =  2
> > > [0, 5]
> > > }
>
> Colin,
>
> I just debugged into the display method. If inputname(1) is an empty
> string, the method could use the variable “argn” to get the coordinates
> within the cell array and produce the desired output.
>
> Oliver

It is not so easy. First, you have to decide whether “argn” represents 
coordinates of a cell-array. You could do this with a regular 
expression, but can't be 100% sure.

Second, you want to get access to the following variable (in ov-base.cc) 
to correctly indent your output. I think there currently is no way to 
access this value from within a m-file display method (unless you use an 
oct-file kludge).
   int octave_base_value::curr_print_indent_level