[pstricks] Check for file version of pstricks-add.tex

[Christoph Bersch]

Hi,

for my package I need a pstricks-add.tex version >= 2.81. Is there a way
to check for this (\RequirePackage does not work, as I want to use a
certain version of the _.tex_ file) and alternatively define the macro
in my package?

\ifversion>=2.81
% include pstricks-add.tex
\else
% use the corresponding code part
\fi

Is this possible and is this a good idea? I need the macro \nlput (the
related code contains only 24 lines).

Thanks
Christoph