Update gnuplot plotting scripts for faster or more modern synta * scripts/plot/__gnuplot_drawnow__.m: Use default values in function header. Check number of arguments to function immediately. Use single quotes to avoid lots of backslashing. Use strtok() to replace hand-coded functionality. Initialize persistent variables in declaration (10% faster). * scripts/plot/gnuplot_binary.in: Replace tabs with spaces. Simplify input validation. Add %!test block. * scripts/plot/private/__gnuplot_get_var__.m: Use default values in function header. Use "*char" in fread to automatically convert to char variable. * scripts/plot/private/__gnuplot_ginput__.m: Check immediately for required version of gnuplot. Use "*char" in fread to automatically convert to char variable. Use fputs in place of fprintf to match rest of code. * scripts/plot/private/__gnuplot_has_feature__.m: Initialize persistent varibles in declaration. Use false () rather than logical (zeros()) construction. * scripts/plot/private/__gnuplot_has_terminal__.m: Use strtok() to replace hand-coded functionality * scripts/plot/private/__gnuplot_print__.m: Replace sprintf calls with direct string char matrix concatenation (2.4x faster) where possible. Replace for loop with multiple argument form of set(). Use single quotes to avoid lots of backslashing. * scripts/plot/private/__gnuplot_version__.m: Use single quotes to avoid lots of backslashing.

## Copyright (C) 2008-2012 David Bateman
##
## 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{r} =} colon (@var{a}, @var{b})
## @deftypefnx {Function File} {@var{r} =} colon (@var{a}, @var{b}, @var{c})
## Method of a class to construct a range with the @code{:} operator.  For
## example:
##
## @example
## @group
## a = myclass (@dots{});
## b = myclass (@dots{});
## c = a : b
## @end group
## @end example
##
## @seealso{class, subsref, subsasgn}
## @end deftypefn

function r = colon (varargin)
  if (nargin != 0)
    error ('colon: not defined for class "%s"', class (varargin{1}));
  endif
endfunction


%!error colon (1)

## FIXME -- what does colon () mean since it doesn't set a return value?