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

[Christoph Bersch]

Herbert Voss schrieb:
> Christoph Bersch schrieb:
> 
>> what is the meaning or purpose of the @beginspecial and @endspecial 
>> procedures in PSTricks?
> 
> holding everything local

Hmm, thats what I feared :-(

>> 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

Right, I didn't think about trying out the usual suspects \pstverb, 
\pstVerb and \pst at Verb.

\pstVerb
    ->   no encapsulating, no dictionary
\pstverb
    ->   @beginspecial ... @endspecial, no dictionary
\pst at Verb
    ->   no encapsulating, tx at Dict dictionary

>> \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.

Thank you!

Christoph