[XeTeX] escaping the pipe

[Mike Maxwell]

Rembrandt Wolpert wrote:
> Have you tried $|$ for the pipe as a way out?

You mean like
    a \{ā$|$c\} d
?  In that case, both '$'s show up, the first one overstriking the 
a-macron.  (The pipe is ok...)

I think I finally have a solution: a 'hair space' (U+200A) between the 
a-macron and the pipe char seems to work, with no noticeable space 
showing up in the PDF.

I started this thread on the assumption that XeTeX (and presumably 
LaTeX) had some special treatment of the pipe char, and I just didn't 
understand.  I guess it does, in tabular environments, but perhaps not 
here?  At any rate, I guess it's a font bug.  Thank you all for your help!

    Mike Maxwell