Mercurial > octave-nkf
view libinterp/octave-value/ov-null-mat.cc @ 20530:bf6c4433ed5f
Clean up isa() function.
* ov-class.cc (Fisa): Remove not strictly necessary const modifiers on
variables. Use more meaningful variable names. Put direct test for
class name first in if tree since this is the most likely test to
succeed.
author | Rik <rik@octave.org> |
---|---|
date | Tue, 22 Sep 2015 01:38:40 -0700 |
parents | 075a5e2e1ba5 |
children |
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/* Copyright (C) 2008-2015 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 <http://www.gnu.org/licenses/>. */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include "ov-null-mat.h" #include "ops.h" #include "defun.h" DEFINE_OV_TYPEID_FUNCTIONS_AND_DATA (octave_null_matrix, "null_matrix", "double"); const octave_value octave_null_matrix::instance (new octave_null_matrix ()); static octave_base_value * default_null_matrix_numeric_conversion_function (const octave_base_value& a) { // The cast is not necessary? // CAST_CONV_ARG (const octave_null_matrix&); return a.empty_clone (); } octave_base_value::type_conv_info octave_null_matrix::numeric_conversion_function (void) const { return octave_base_value::type_conv_info (default_null_matrix_numeric_conversion_function, octave_matrix::static_type_id ()); } DEFINE_OV_TYPEID_FUNCTIONS_AND_DATA (octave_null_str, "null_string", "char"); const octave_value octave_null_str::instance (new octave_null_str ()); static octave_base_value * default_null_str_numeric_conversion_function (const octave_base_value& a) { // The cast is not necessary? // CAST_CONV_ARG (const octave_null_str&); return a.empty_clone (); } octave_base_value::type_conv_info octave_null_str::numeric_conversion_function (void) const { return octave_base_value::type_conv_info (default_null_str_numeric_conversion_function, octave_char_matrix_str::static_type_id ()); } DEFINE_OV_TYPEID_FUNCTIONS_AND_DATA (octave_null_sq_str, "null_sq_string", "char"); const octave_value octave_null_sq_str::instance (new octave_null_sq_str ()); static octave_base_value * default_null_sq_str_numeric_conversion_function (const octave_base_value& a) { // The cast is not necessary? // CAST_CONV_ARG (const octave_null_sq_str&); return a.empty_clone (); } octave_base_value::type_conv_info octave_null_sq_str::numeric_conversion_function (void) const { return octave_base_value::type_conv_info (default_null_sq_str_numeric_conversion_function, octave_char_matrix_sq_str::static_type_id ()); } DEFUN (isnull, args, , "-*- texinfo -*-\n\ @deftypefn {Built-in Function} {} isnull (@var{x})\n\ Return true if @var{x} is a special null matrix, string, or single quoted\n\ string.\n\ \n\ Indexed assignment with such a value on the right-hand side should delete\n\ array elements. This function should be used when overloading indexed\n\ assignment for user-defined classes instead of @code{isempty}, to\n\ distinguish the cases:\n\ \n\ @table @asis\n\ @item @code{A(I) = []}\n\ This should delete elements if @code{I} is nonempty.\n\ \n\ @item @code{X = []; A(I) = X}\n\ This should give an error if @code{I} is nonempty.\n\ @end table\n\ @seealso{isempty, isindex}\n\ @end deftypefn") { octave_value retval; int nargin = args.length (); if (nargin == 1 && args(0).is_defined ()) retval = args(0).is_null_value (); else print_usage (); return retval; } /* %!assert (isnull ([]), true) %!assert (isnull ([1]), false) %!assert (isnull (zeros (0,3)), false) %!assert (isnull (""), true) %!assert (isnull ("A"), false) %!assert (isnull (''), true) %!assert (isnull ('A'), false) %!test %! x = []; %! assert (isnull (x), false); */