########################################################################
##
## Copyright (C) 2021 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################

## -*- texinfo -*-
## @deftypefn {} {@var{tf} =} isStringScalar (@var{s})
## Return true if @var{s} is a string scalar.
##
## @seealso{isstring, isscalar}
## @end deftypefn

function retval = isStringScalar (s)

  if (nargin != 1)
    print_usage ();
  endif

  retval = isstring (s) & isscalar (s);

endfunction


%!assert (isStringScalar ([]), false);
%!assert (isStringScalar (1), false);
%!assert (isStringScalar ('a'), false);
## FIXME: when string arrays are implemented, this should be uncommented.
#%!assert (isStringScalar (""), true);
#%!assert (isStringScalar ("a"), true);
#%!assert (isStringScalar ("ab"), true);
#%!assert (isStringScalar (["a", "b"]), false);
#%!assert (isStringScalar (["a"; "b"]), false);
%!assert (isStringScalar ({'a'}), false);
%!assert (isStringScalar ({"a"}), false);
%!assert (isStringScalar (struct ("a", "b")), false);

%!error <Invalid call> isStringScalar ();
%!error isStringScalar ("a", "b");
%!error [a, b] = isStringScalar ("a", "b");
