[pstricks] exclamation mark

[Christoph Bersch]

Doris Wagner schrieb:
> 
> sometimes in pstricks-code there are expressions like this:
> 
> linecolor=gray!20
> 
> I guess that the exclamation mark is something postscript-specific. Can 
> anyone explain the meaning of this exclamation mark or tell me where I 
> can find something about it in the web?

Not every exclamation mark has something to do with postscript :-)

In your case it is the syntax of the color definitions in the paket 
xcolor 
(ftp://dante.ctan.org/tex-archive/macros/latex/contrib/xcolor/xcolor.pdf)

In contrast if you have something like this

\pnode(! 2 5 div 9 sqrt){Node}

the ! indicates that raw postscript code follows that (in this simple 
case) must evaluate to a coordinate pair (here 0.4 3)

Hope that helps a bit

Christoph