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[CreaPhase.git] / octave_packages / m / miscellaneous / getfield.m

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+## Copyright (C) 2000-2012 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{v1}, @dots{}] =} getfield (@var{s}, @var{key}, @dots{})
+## Extract a field from a structure (or a nested structure).  For example:
+##
+## @example
+## @group
+## ss(1,2).fd(3).b = 5;
+## getfield (ss, @{1,2@}, "fd", @{3@}, "b")
+##    @result{} 5
+## @end group
+## @end example
+##
+## Note that the function call in the previous example is equivalent to
+## the expression
+##
+## @example
+## @group
+## i1 = @{1,2@}; i2 = "fd"; i3 = @{3@}; i4= "b";
+## ss(i1@{:@}).(i2)(i3@{:@}).(i4)
+##    @result{} 5
+##
+## @end group
+## @end example
+## @seealso{setfield, rmfield, isfield, isstruct, fieldnames, 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)