Two questions

1. I note that help for the postscript device claims "The 
postscript produced by R is EPS (Encapsulated PostScript)
compatible...".  It does not say it is EPS *compliant*.  
Indeed, the EPS produced by R includes a \showpage command 
which I believe (not that I'm an expert!) non-standard EPS.  
My question:  Is there any reason why it is EPS compatible,
but not compliant?  (I ask because the \showpage caused me
a minor trouble once.)

Adobe's tech documents are here:

http://partners.adobe.com/asn/developer/technotes/postscript.html

  and says

"The showpage operator is permitted in EPS files because it is present 
in so many PostScript language files. Therefore, it is reasonable for an 
EPS file to use the showpage operator, although it is not necessary if 
the EPS file will only be imported into another document. The 
application importing the EPS file is responsible for redefining showpage."

  So it seems that any problem you had with showpage was possibly the 
importing application's fault.

  I've just realised I've been hacking PS files for 15 years now...

Barry Rowlingson
Maths and Stats
Lancaster University
Lancaster, UK