[luatex] Hyphenation on ligatures

[Reinhard Kotucha]

On 2016-02-12 at 21:32:40 +0700, Igor Liferenko wrote:

 > Can anybody explain why and how luatex hyphenates on ligatures? Is
 > this incompatibility with TeX intentional, or is it just a bug
 > which has not been fixed?

I don't think that it's deprecated to hyphenate at ligatures in
general.  This heavily depends on the language and maybe other
constraints.

A problem is that TeX doesn't know when a ligature is appropriate
or not.  At least in German, ligatures are deprecated at boundaries of
composed words.

Consider the German word Auflage.  The fl-ligature is deprecated and
LaTeX users write

  \usepackage[german]{babel}
  ....
  Auf"|lage

in order to avoid the ligature.  Nevertheless, Auf-lage is a good
hyphenation point despite the ligature, even if it wasn't disabled
manually.

On the other hand I suppose that the Dutch ij-ligature shall never be
hyphenated.  But with proper hyphenation patterns it won't happen
anyway.

Regards,
  Reinhard

-- 
------------------------------------------------------------------
Reinhard Kotucha                            Phone: +49-511-3373112
Marschnerstr. 25
D-30167 Hannover                    mailto:reinhard.kotucha at web.de
------------------------------------------------------------------