## Copyright (C) 1994-2019 John W. Eaton
## Copyright (C) 2009 Jaroslav Hajek
##
## 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 {} {} strcat (@var{s1}, @var{s2}, @dots{})
## Return a string containing all the arguments concatenated
## horizontally.
##
## If the arguments are cell strings, @code{strcat} returns a cell string
## with the individual cells concatenated.  For numerical input, each element
## is converted to the corresponding ASCII character.  Trailing white space
## for any character string input is eliminated before the strings are
## concatenated.  Note that cell string values do @strong{not} have
## whitespace trimmed.
##
## For example:
##
## @example
## @group
## strcat ("|", " leading space is preserved", "|")
##     @result{} | leading space is preserved|
## @end group
## @end example
##
## @example
## @group
## strcat ("|", "trailing space is eliminated ", "|")
##     @result{} |trailing space is eliminated|
## @end group
## @end example
##
## @example
## @group
## strcat ("homogeneous space |", "  ", "| is also eliminated")
##     @result{} homogeneous space || is also eliminated
## @end group
## @end example
##
## @example
## @group
## s = [ "ab"; "cde" ];
## strcat (s, s, s)
##     @result{}
##         "ababab   "
##         "cdecdecde"
## @end group
## @end example
##
## @example
## @group
## s = @{ "ab"; "cd " @};
## strcat (s, s, s)
##     @result{}
##         @{
##           [1,1] = ababab
##           [2,1] = cd cd cd
##         @}
## @end group
## @end example
##
## @seealso{cstrcat, char, strvcat}
## @end deftypefn

function st = strcat (varargin)

  if (nargin == 0)
    st = "";
  elseif (nargin == 1)
    if (iscellstr (varargin{1}))
      st = varargin{1};
    elseif (isreal (varargin{1}) || ischar (varargin{1}))
      st = char (cellstr (varargin{1}));
    else
      error ("strcat: inputs must be strings or cells of strings");
    endif
  else
    ## Convert to cells of strings
    uo = "uniformoutput";
    reals = cellfun ("isreal", varargin);
    if (any (reals))
      varargin(reals) = cellfun ("char", varargin(reals), uo, false);
    endif
    chars = cellfun ("isclass", varargin, "char");
    allchar = all (chars);
    varargin(chars) = cellfun ("cellstr", varargin(chars), uo, false);
    if (! all (cellfun ("isclass", varargin, "cell")))
      error ("strcat: inputs must be strings or cells of strings");
    endif

    ## We don't actually need to bring all cells to common size, because
    ## cellfun can now expand scalar cells.
    err = common_size (varargin{:});

    if (err)
      error ("strcat: arguments must be the same size, or be scalars");
    endif

    ## Cellfun handles everything for us.
    st = cellfun ("horzcat", varargin{:}, uo, false);

    if (allchar)
      ## If all inputs were strings, return strings.
      st = char (st);
    endif
  endif

endfunction


## test the dimensionality
## 1d
%!assert (strcat ("ab ", "ab "), "abab")
%!assert (strcat ({"ab "}, "ab "), {"ab ab"})
%!assert (strcat ("ab ", {"ab "}), {"abab "})
%!assert (strcat ({"ab "}, {"ab "}), {"ab ab "})
%!assert (strcat ("", "ab"), "ab")
%!assert (strcat ("", {"ab"}, {""}), {"ab"})
## 2d
%!assert (strcat (["ab ";"cde"], ["ab ";"cde"]), ["abab  ";"cdecde"])

## test for deblanking implied trailing spaces of character input
%!assert (strcat ("foo", "bar"), "foobar")
%!assert (strcat (["a "; "bb"], ["foo"; "bar"]), ["afoo "; "bbbar"])

## test for mixing character and cell inputs
%!assert (strcat ("a", {"bc", "de"}, "f"), {"abcf", "adef"})

## test for scalar strings with vector strings
%!assert (strcat (["a"; "b"], "c"), ["ac"; "bc"])

## test with cells with strings of differing lengths
%!assert (all (strcmp (strcat ({"a", "bb"}, "ccc"), {"accc", "bbccc"})))
%!assert (all (strcmp (strcat ("a", {"bb", "ccc"}), {"abb", "accc"})))

## test with a single string or cell input
%!assert <*49094> (strcat ("foo    "), "foo")
%!assert <*49094> (strcat ({"foo"}), {"foo"})

%!assert (strcat (1), char (1))
%!assert (strcat (1, 2), strcat (char (1), char (2)))
%!assert (strcat ("", 2), strcat ([], char (2)))

%!assert (strcat (), "")