# Why does my RPN expression to find a distance of 2 nodes produce a wrong output?

I want to find a variant for the following,

\documentclass[pstricks,border=12pt]{standalone}
\usepackage{pst-eucl}
\begin{document}
\begin{pspicture}[showgrid](-2,-2)(2,2)
\pstGeonode[PosAngle={180,45,-90}]
(-1.5,-1){A}
(1.5,1){B}
(1.5,-1){C}
\pstRightAngle[RightAngleSize=0.2,fillstyle=solid,fillcolor=green!50]{A}{C}{B}
\pstArcOAB[arcsepB=-1,arcsepA=-2.5]{A}{B}{B}
\pstCurvAbsNode[CurvAbsNeg=true,PointName=none]{A}{B}{D}{\pstDistVal{.75}}
\psline[linestyle=dashed](A)(D)(D|C)(C)
\psset{shortput=nab,labelsep=-3pt}
\ncline{A}{B}^{$g$}
\ncline{B}{C}^{$a$}
\ncline{C}{A}^{$b$}
\end{pspicture}
\end{document}


by calculating the distance with Pyth2 operator.

The following is my attempt.

\documentclass[pstricks,border={12pt 12pt 2cm 12pt}]{standalone}
\usepackage{pst-eucl}
\psset{saveNodeCoors}
\begin{document}
\begin{pspicture}[showgrid](-2,-2)(2,2)
\pstGeonode[PosAngle={180,45,-90}]
(-1.5,-1){A}
(1.5,1){B}
(1.5,-1){C}
\pstRightAngle[RightAngleSize=0.2,fillstyle=solid,fillcolor=green!50]{A}{C}{B}
\pstVerb{/Dist {N-A.x N-A.y N-B.x N-B.y Pyth2} def}%
\pnode(!Dist 10 PtoC){D}
\psarc[arcsepB=-1,arcsepA=-2.5](A){!Dist}{(D)}{(B)}
\psline[linestyle=dashed](A)(D)(D|C)(C)
\psset{shortput=nab,labelsep=-3pt}
\ncline{A}{B}^{$g$}
\ncline{B}{C}^{$a$}
\ncline{C}{A}^{$b$}
\end{pspicture}
\end{document}


And its output below is different from the first version shown above.

Could you find the glitch?

-
I tried with \pnode[!N-A.x N-A.y](!Dist 20 PtoC){D} but it still produces a wrong output. – kiss my armpit Mar 12 '13 at 15:11

\pnode[A](!Dist 10 PtoC ){D}

But why does \pnode[!N-A.x N-A.y](!Dist 20 PtoC){D} not work while \pnode[!\psGetNodeCenter{A} A.x A.y](!Dist 20 PtoC){D} works? It is really confusing. :D – kiss my armpit Mar 12 '13 at 15:26
I canceled my comment above. Apparently both are identical. They became different because of the presence of a trailing space at the end of \pstRightAngle. – kiss my armpit Mar 15 '13 at 0:05