[XeTeX] Font protrusion --- new or old ?

[Jonathan Kew]

On 8 Feb 2009, at 20:28, Stephen Moye wrote:
>
> Your warning about recursion is ominous... When would that
> rear its ugly head?

It would happen if the interchar toks didn't include  
\XeTeXinterchartokenstate=0, because there'd be a new boundary between  
what just got inserted and the character that was already there. So  
that's why that's there (within a group, so it doesn't get permanently  
switched off, of course).

JK