[Xy-pic] problem with color option

[Jürgen Koslowski]

Hello,

I ran into a problem with the color option.  While TeX and dvips do not
complain about a line like

\newxycolor{lightgray}{0.8 gray}

ghostscript produces an error message when trying to display the resulting
PostScript file.  This happens under ghostscript 5.50 as well as 7.05.
Explicitly, the former complains about

Error: /typecheckGNU Ghostscript: Unrecoverable error, exit code 1
 in --setgray--
Operand stack:
   --dict:915/1241(G)--
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1   3   %oparray_pop   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--
Dictionary stack:
   --dict:915/1241(G)--   --dict:0/20(G)--   --dict:65/200(L)--   --dict:201/300(L)--
Current allocation mode is local
Current file position is 516545
Error: /typecheck in --setgray--GNU Ghostscript: Unrecoverable error, exit code 1

On the other hand, if I emulate the definitions in xycolor.tex by setting

\catcode`\@=11
 \newxycolor@{lightgray}{0.8}{gray}{}\relax
\catcode`\@=12

everything is fine.  Any ideas?

-- 
Juergen Koslowski               If I don't see you no more on this world
ITI, TU Braunschweig               I'll meet you on the next one
koslowj at iti.cs.tu-bs.de               and don't be late!
http://www.iti.cs.tu-bs.de/~koslowj      Jimi Hendrix (Voodoo Child, SR)