%% 
%%  A DANTE-Edition example
%% 
%%  Example C-03-2 on page 850.
%% 
%%  Copyright (C) 2010 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{article}
\pagestyle{empty}
\setlength\textwidth{201.70511pt}
\setlength\parindent{0pt}

\usepackage{pst-node}\SpecialCoor

\begin{document}
\begin{pspicture}(3,-3)
  \newcommand{\correct}{%
    \pnode(0,0){A} \pnode(2,0){B} %
    \psline[linestyle=dashed](A)(B)}
  \pcline[linewidth=2pt](0,0)(3,-3)
  \naput{\correct}\nbput{correct}% correct
  \renewcommand{\correct}{%
    \pnode(0,0){A} \pnode(2,0){B}%
    \ncline[linestyle=dashed]{A}{B}}\hfill
  \pcline[linewidth=2pt](0,0)(3,-3)
  \naput{\correct}\nbput{wrong}% wrong
\end{pspicture}
\end{document}
