[pstricks] Optional {} argument as in \psline{->}()()

[Herbert Voss]

Christoph Bersch schrieb:

> for my package pst-optexp I want to allow an optional {} argument like 
> the arrow argument in \psline: \psline{->}(A)(B)

this is one of the wrong ideas of Timothy van Zandt,
spoken with his words ... ;-)

> At the moment all my components are defined in the following way.
> 
> \def\lens{\@ifnextchar[{\pst at lens}{\pst at lens[]}}

use always

\def\pstlens{\pst at object{pstlens}}
\def\pstlens at i(#2)(#3)#4{%
   \pst at killglue
   \addbefore at par{...} % the defaults
   \begingroup
   \use at par
   ....
>     \pst at regNodes{#2}{#3}%
>     \pst at draw@component{#1}{#4}\pst at draw@lens%

   \endgroup%
   \ignorespaces}

Optional arguments should be passed by pst-xkey


Herbert