problem with sorting

[John W. Eaton]

I noticed this problem:

  octave:1> typeinfo (int8 ([1,2;3,4]))
  ans = int8 matrix
  octave:2> typeinfo (sort (int8 ([1,2;3,4])))
  ans = matrix

I think this should return an int8 matrix, to match the type of the
argument passed to sort.

In src/DLD-FUNCTIONS/sort.cc, we dispatch on type and only handle
NDArray, ComplexNDArray, charNDArray, and Cell objects.  Integer
values are converted to NDArary objects, then sorted.

How should we fix this?  Should we add a sort method to the
octave_value class hierarchy?  That way the dispatching can be handled
by virtual methods in the octave_value class.  Does anyone see
disadvantages to doing that?

jwe