[Dev-luatex] Recalculating tail of the list in ligaturing callback

[Hans Hagen]

On 11/14/2018 2:42 PM, Marcel Krüger wrote:

> Now `run_lua_ligkern_callback` always returns the tail parameter without change,
> so I am pretty sure `tail` is never `null`.

not true ... the callback can be any function and there doesn't have to 
be a tail returned .... if you want to recalculate, just make sure you 
return only head

\directlua{callback.register('ligaturing',
   function(...) return (node.ligaturing(...)) end
}ffi\bye

so no fundamental changes will happen (if only because something that 
works better for you might fail or have side effects (functional or 
performance) for others)

Hans

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