## Copyright (C) 2019, 2023, 2024 Andrew Janke <floss@apjanke.net>
##
## This file is part of Tablicious.
##
## 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 {Function} {[@var{out1}, @var{out2}, @dots{}, @var{outN}] =} scalarexpand @
##   (@var{x1}, @var{x2}, @dots{}, @var{xN})
##
## Expand scalar inputs to match size of non-scalar inputs.
##
## Expands each scalar input argument to match the size of the non-scalar
## input arguments, and returns the expanded values in the corresponding
## output arguments. @code{repmat} is used to do the expansion.
##
## Works on any input types that support @code{size}, @code{isscalar}, and
## @code{repmat}.
##
## It is an error if any of the non-scalar inputs are not the same size as
## all of the other non-scalar inputs.
##
## Returns as many output arguments as there were input arguments.
##
## Examples:
##
## @example
## x1 = rand(3);
## x2 = 42;
## x3 = magic(3);
## [x1, x2, x3] = scalarexpand (x1, x2, x3)
## @end example
##
## @end deftypefn
function varargout = scalarexpand (varargin)
  sz = [];

  for i = 1:nargin
    if (! isscalar (varargin{i}))
      sz_i = size (varargin{i});
      if (isempty (sz))
        sz = sz_i;
      else
        if (! isequal (sz, sz_i))
          error ('Matrix dimensions must agree (%s vs %s)',...
            tblish.internal.chrono.size2str (sz), tblish.internal.chrono.size2str (sz_i))
        endif
      endif
    endif
  endfor

  varargout = varargin;

  if (isempty (sz))
    return
  endif

  for i = 1:nargin
    if (isscalar (varargin{i}))
      varargout{i} = repmat (varargin{i}, sz);
    endif
  endfor

endfunction


%!shared a, b, c
%!  [a, b, c] = scalarexpand (1, magic (3), {'foo'});
%!assert (isequal (size (a), [3 3]))
%!assert (isequal (size (b), [3 3]))
%!assert (isequal (size (b), [3 3]))
%!assert (isa (a, 'double'))
%!assert (isa (a, 'double'))
%!assert (isa (c, 'cell'))
