[luatex] Request for Callback

[Élie Roux]

>> it would complicate the already complex algorithm and once we start
>> adding callbacks *in* core mechanisms we notonly get a slow down but
>> also an endless list of additional subcallbacks and dependencies
>
> I'll think about this anyway, but I suspect Hans is right, and that
> there is no 'good' spot to insert callbacks within the line breaking,
> and doing the whole thing in lua may well be the best solution.

Dear all,

Thank you very much for your answer! I suspected this kind of 
difficulties, and I trust you know better than me if it's doable or not.

By the way, Hans, I heard you already reimplemented the TeX linebreak 
algorithm in pure Lua, can your code be found somewhere?

Thank you!
-- 
Elie