## Copyright (C) 1996, 1997 John W. Eaton
##
## 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 2, 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, write to the Free
## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
## 02110-1301, USA.

## -*- texinfo -*-
## @deftypefn {Function File} {} logical (@var{arg})
## Convert @var{arg} to a logical value.  For example,
##
## @example
## logical ([-1, 0, 1])
## @end example
##
## @noindent
## is equivalent to
##
## @example
## [-1, 0, 1] != 0
## @end example
## @end deftypefn

## Author: jwe

function y = logical (x)

  if (nargin == 1)
    if (islogical (x) || isempty (x))
      y = x;
    elseif (isnumeric (x))
      y = x != 0;
    else
      error ("logical not defined for type `%s'", typeinfo (x));
    endif
  else
    usage ("logical (x)");
  endif

endfunction