doc: Update documentation for functions in octave-value dir. * ov-bool-mat.cc (Flogical): Document that input must be numeric. Document incompatibility with Matlab regarding complex inputs. * ov-cell.cc (Fcell): Add seealso references. * ov-cell.cc (Fcellstr): Document that trailing spaces are trimmed. Add seealso references. * ov-cell.cc (Fstruct2cell): Use lowercase names in @var references. * ov-class.cc (Fismethod): Add seealso reference to isprop. * ov-class.cc (Fsuperiorto): Add seealso reference to inferiorto. * ov-class.cc (Finferiorto): Add seealso reference to superiorto. * ov-fcn-handle.cc (Ffunctions): Add table to documentation describing return values. * ov-fcn-handle.cc (Ffunc2str): Add seealso links to str2func, functions. * ov-fcn-handle.cc (Fstr2func): Add seealso links to func2str, inline. * ov-fcn-handle.cc (Fis_function_handle): Add seealso links to functions. * ov-fcn-inline.cc (Finline): Add note that the use of inline is discouraged. Add seealso link to str2func. * ov-int16.cc (Fint16): Add seealso links to docstring. * ov-int32.cc (Fint32): Add seealso links to docstring. * ov-int64.cc (Fint64): Add seealso links to docstring. * ov-int8.cc (Fint8): Add seealso links to docstring. * ov-oncleanup.cc (FonCleanup): clarify docstring by using "function" rather than "action" for what gets called when onCleanup object is destroyed. * ov-struct.cc (Fstruct): Add additional calling forms. Add seealso links. * ov-struct.cc (Fisfield): Add additional calling forms. Add seealso link. * ov-struct.cc (Fnfields): Add seealso link. * ov-struct.cc (Fcell2struct): Add additional calling forms. Add seealso link. * ov-struct.cc (Frmfield): Emphasize that a copy of the struct is returned. Add seealso link. * ov-struct.cc (Fstruct_levels_to_print): Add seealso link to print_struct_array_contents. * ov-struct.cc (Fprint_struct_array_contents): Add seealso link to struct_levels_to_print. * ov-typeinfo.cc (Ftypeinfo): Add seealso links to class, isa. * ov-uint16.cc (Fuint16): Add seealso links to docstring. * ov-uint32.cc (Fuint32): Add seealso links to docstring. * ov-uint64.cc (Fuint64): Add seealso links to docstring. * ov-uint8.cc (Fuint8): Add seealso links to docstring. * ov-usr-fcn.cc (Fnargin): Add example based on 'union' function. * ov-usr-fcn.cc (Fnargout): Add example based on 'imread' function. * ov-usr-fcn.cc (Foptimize_subsasgn_calls): Improve docstring. * ov.cc (Fsubsref): Rephrase one sentence. * fieldnames.m: Add more functions to seealso links. * getfield.m: Re-order seealso links. * setfield.m: Re-order seealso links. * isprop.m Add ismethod, isobject to seealso links.

## Copyright (C) 2000-2013 Etienne Grossmann
## Copyright (C) 2009 VZLU Prague
##
## 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
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn  {Function File} {[@var{val}] =} getfield (@var{s}, @var{field})
## @deftypefnx {Function File} {[@var{val}] =} getfield (@var{s}, @var{idx1}, @var{field1}, @var{idx2}, @var{field2}, @dots{})
## Extract a field from a structure (or a nested structure).  The syntax
## is the same as @code{setfield}, except it omits the final @var{val}
## argument, returning this value instead of setting it.
##
## @seealso{setfield, rmfield, isfield, fieldnames, isstruct, struct}
## @end deftypefn

## Author: Etienne Grossmann <etienne@cs.uky.edu>

function obj = getfield (s, varargin)
  if (nargin < 2)
    print_usage ();
  endif
  subs = varargin;
  flds = cellfun ("isclass", subs, "char");
  idxs = cellfun ("isclass", subs, "cell");
  if (all (flds | idxs))
    typs = merge (flds, {"."}, {"()"});
    obj = subsref (s, struct ("type", typs, "subs", subs));
  else
    error ("getfield: invalid index");
  endif
endfunction


%!test
%! x.a = "hello";
%! assert (getfield (x, "a"), "hello");
%!test
%! ss(1,2).fd(3).b = 5;
%! assert (getfield (ss,{1,2},"fd",{3},"b"), 5);