[pstricks] Meaning of @beginspecial, @endspecial and @setspecial

[Herbert Voss]

Christoph Bersch schrieb:

> what is the meaning or purpose of the @beginspecial and @endspecial 
> procedures in PSTricks?

holding everything local

> I noticed, that variables defined within
> @beginspecial ... @endspecial cannot be accessed in Postscript code. 
> Some code, however, is not enclosed by those procedures. That is the 
> reason why the following gives a Postscript error (bad code, only for 
> demonstration!):
> 

\pstVerb{/asdf 3 def}
\psline(2,1)(! 5 asdf)

works, beacuse the argument is set without a @beginspecial ... @endspecial

> \psline(!/asdf 3 def 0 0)(3, 3)
> \psline(2,1)(! 5 asdf)
> 
> whereas
> 
> \pnode(!/asdf 3 def 0 0){A}
> \psline(2,1)(! 5 asdf)
> 
> work.

nodes are set global to make them available ouside a pspicture
environment.

Herbert