[Xy-pic] bizarre bug

[Juergen Koslowski]

Hello,

In order to mark finite states in automata with double circles I
defined a macro

\def\rin#1{**{+<3 pt>[o][F]}#1}

to be used in matrices where every node is surrounded by a circle.

Strangely enough, I just found out that in the presence of subscripts
in the state's name the success of this procedure depends on whether the
subscript is a number or a letter:

\[\xymatrix at C+8 pt@*[F]@*[o]@*+<3 pt>{
  \rin q_0
 &\rin q_n
}
\]

What's going on here?

-- Jürgen

-- 
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)