# [pstricks] Bookkeeping in pspicture environment

Christoph Bersch usenet at bersch.net
Tue Jul 22 17:12:41 CEST 2008

Herbert Voss schrieb:
> Christoph Bersch schrieb:
>
>> in the next pst-optexp version I want to integrate some kind of
>> bookkeeping for named objects. The names are defined with a parameter
>> 'compname'. The names are registered in a global list and before every
>> new definition it is checked if the name was already used.
>>
>> Now this bookkeeping should be local in every pspicture environment. I
>> thought of doing this by redefining \pspicture as follows:
>>
>> \let\old at pspicture\pspicture
>> \def\pspicture{\let\@complist\@empty\old at pspicture}%
>>
>> A working example would then be
>
> [ ... ]
>
>> This seems to work... The problem does not raise any PackageWarning,
>> only when uncommenting the last \psset{...} it is raised, as expected.
>>
>> Are there any problems to be expected with my solution or do you have a
>> better suggestion how to solve this issue?
>
> everything inside the pspicture environment is local. If
> I understand well, then you want the list also be local.
>
[same code]
>            \edef\@complist{\@complist\ifx\@complist\@empty\else,\fi#1}%
[same code]

Sorry, I see, that my example was too minimal to show the issue.
The point is, that the parameter 'compname' is set only within an object
(i.e. in a surrounding  group). Therefore, I need the \xdef\@complist in
order to change \@complist outside of the group.
The following example should now reproduce more exactly the problem:

\documentclass{article}
\usepackage{pst-xkey}
\usepackage{pstricks}
\makeatletter
\let\old at pspicture\pspicture
\def\pspicture{\let\@complist\@empty\old at pspicture}%
\define at key[psset]{}{compname}{%
\edef\pst at temp{#1}%
\ifx\pst at temp\@empty\else
\@expandtwoargs\in@{,#1,}{,\@complist,}%
\ifin@
\PackageWarning{}%
{^^Jcompname '#1' already used.^^J}%
\else
% Use definition of \XKV at addtolist@x with an \xdef instead
% of \edef in order to keep the bookkeeping global
\xdef\@complist{\@complist\ifx\@complist\@empty\else,\fi#1}%
\fi
\fi
}%
\makeatother
\begin{document}
\begin{pspicture}(5,5)
\begingroup
\psset{compname=Name}
\endgroup
\end{pspicture}
\begin{pspicture}(5,5)
\begingroup
\psset{compname=Name}
\endgroup
\begingroup
%     \psset{compname=Name}
\endgroup
\end{pspicture}
\end{document}

Thank you,
Christoph