[pstricks] pst-add, algebraic=true

[D. P. Story]

I've noticed a minor problem when the algebraic option is use for 
\psplot.

If you run compile the document below using line (*) (graph the 
function -x^2+6*x-5), you get either no graph or a straight line. The 
problem seems to manifest itself when the leading term is a negative 
sign.  If I define the function as  0-x^2+6*x-5 and comple the 
document below using line (**) instead of (*), the parabola appears 
as expected.

Seems to be a bug, but can be worked around.

dps

\documentclass{article}
\usepackage{pstricks}
\usepackage{pst-plot}
\usepackage{pstricks-add}
\pagestyle{empty}

\begin{document}

\begin{center}
\psset{algebraic=true,plotpoints=100}
\begin{pspicture}(-0.5,-0.5)(7,5)
  \psaxes[xyLabel=\footnotesize]{->}(0,0)(-0.5,-0.5)(7,5)
  \psplot[linewidth=1pt]{0}{5}{-x^2+6*x-5}  % (*)
%  \psplot[linewidth=1pt]{0}{5}{0-x^2+6*x-5}   % (**)
\end{pspicture}
\end{center}

\end{document}