# What causes this error? [closed]

After seeing Herbert's answer, apparently this problem should not occur if I realized the first row of the following code should be \documentclass{beamer}. Problems often come from not knowing what I am doing.

Please close this too localized question.

\documentclass{article}
\usepackage{filecontents}
\begin{filecontents*}{pst-sex.sty}
% ========================================================
% Copyright (c) 2013 Bugbusters. All rights reservered.
% LPPL LaTeX Public Project License
% ========================================================
\NeedsTeXFormat{LaTeX2e}[1994/06/01]
\ProvidesPackage{pst-sex}[2013/04/23 v3.141592654 Constant declator for StackEXchange]
\RequirePackage[nomessages]{fp}
\RequirePackage{pstricks}

% removing a trailing space in the original fp.sty
\def\FP@pow#1#2#3{%
% #1 macro, which gets the result
% #2 base
% #3 exponent
%
\FP@beginmessage{POW}%
%
{\def\FP@beginmessage##1{}%
\def\FP@endmessage##1{}%
%
\FPifzero{#2}%
\FP@pow@zero{#3}%
\else%
\FPln\FP@tmpd{#2}%
\FPmul\FP@tmpd\FP@tmpd{#3}%
\FPexp\FP@tmp\FP@tmpd%
\fi%
%
\global\let\FP@tmp\FP@tmp%
}%
%
\FP@endmessage{}%
%
\let#1\FP@tmp%
}

% constants declarator
\newcommand\const[3][]{%
\if\relax\detokenize{#1}\relax
\edef\pst@@sex@@temporary{#3}%
\else
\edef\pst@@sex@@temporary{round(#3:#1)}%
\fi
\expandafter\FPeval\csname#2\expandafter\endcsname
\expandafter{\expandafter{\pst@@sex@@temporary}}%

\def\pst@@picture@i[#1]#2(#3,#4){%
\renewcommand\const[3][]{%
\if\relax\detokenize{##1}\relax
\edef\pst@@sex@@temporary{##3}%
\else
\edef\pst@@sex@@temporary{round(##3:##1)}%
\fi
\expandafter\FPeval\csname##2\expandafter\endcsname
\expandafter{\expandafter{\pst@@sex@@temporary}}%
\pstVerb{/##2 \csname##2\endcsname\space def}\ignorespaces}%
\@ifnextchar(% ignore anything between [] and ()

\endinput
% pst-sex.sty
\end{filecontents*}

\usepackage{multido}
\usepackage{pst-sex}
\usepackage[tightpage]{preview}
\PreviewEnvironment{pspicture}
\PreviewBorder=25pt\relax

\SpecialCoor
\const{Side}{root(2,17)}% the square root of 17

\begin{document}
\begin{frame}
\begin{pspicture}(\Side,\Side)
\psframe(!Side dup)\pause
\multido{\i=0+30}{12}{%
\const[7]{temp}{cos(\i*pi/180)}
\rput{\i}(!Side 2 div dup 2 copy temp mul add 3 1 roll \i\space sin mul add){$\temp$}\pause
}
\end{pspicture}
\end{frame}
\end{document}


What causes this error?

-
Sorry for the bad title because I have no idea to make it more specific and descriptive to convey the exact issue. So feel free to edit the title to suit your preference. :-) –  Weirdstress Function Apr 27 '13 at 7:02
I think you should try to minimise your code -- remove any lines that can be removed while preserving the error. For instance, I just tried removing everything between \begin{pspicture}(\Side,\Side) and \end{pspicture} and the error was still the same. This way you might be able to zoom in on the source of the error. –  John Wickerson Apr 27 '13 at 7:28
@JohnWickerson: The problem has been fixed. It is about my fault. I used article that should be beamer. –  Weirdstress Function Apr 27 '13 at 7:50
Most "bugs" with LaTeX system are user problems. –  kan Apr 27 '13 at 7:51
@kan: And bugs come from not knowing what we are doing. –  Weirdstress Function Apr 27 '13 at 7:53

## closed as too localized by Werner, Marco Daniel, Kurt, mafp, ThorstenApr 27 '13 at 13:31

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it maybe a good idea to choose the correct documentclass ;-)

\documentclass{article}
[ ... ]


but you are using the frame environment ...

However, with the current pstricks.tex from http://texnik.dante.de/tex/generic/pstricks/ I can do something like:

\documentclass{beamer}
\usepackage{pst-tools,multido}
\SpecialCoor

\begin{document}
\begin{frame}{title}
\begin{pspicture}(-4.5,-4.5)(4.5,4.5)
\psframe(+{-sqrt(17)/2}, x)(+{sqrt(17)/2}, x)\pause
\multido{\iA=0+30}{12}{\rput{\iA}(1;\iA){\psPrintValue[algebraic]{\iA, cos(x*Pi/180)}}\pause}
\end{pspicture}
\end{frame}
\end{document}


-
Adding a new feature to allow points in all PSTricks graphic objects to accept node expressions is a good idea. For example: \pnode(2,3){A}\pnode(3,1){B}\psline(.5(B)-.25(A))\rput((A)-(B)){...}\pscircle(2‌​(B)-3(A)){3}. :-) –  Weirdstress Function Apr 27 '13 at 8:08
There is a typo in pstricks.tex (click me). –  Weirdstress Function Apr 27 '13 at 18:28