[luatex] Kerning: when does it not work?

[taco]

Heilmann, Till A. wrote:
> 
>> From Khaled Hosny, Ulrike Fischer, Philipp Lehmann and others I
>> learn that a fundamental issue (if not the _one_ cause for all the
>> seemingly diverse problems I encounter) is the existence of
>> penalized breakpoints: Even if no line breaking occurs the kerning
>> is suppressed at that point. Philipp told me that this was a
>> long-standing limitation of TeX that apparently has not been lifted
>> in LuaTeX.

That limitation is indeed still there, but technically it would not be 
very hard to remove it. I'll add a preliminary tracker item and discuss 
it with Hans.

Best wishes,
Taco