[Dev-luatex] A few newbie questions

[David Kastrup]

Hans Hagen <pragma at wxs.nl> writes:

> Yue Wang wrote:
>>
>> From my experience LuaTeX's result is very different from pdfTeX's
>> result. The most notable one is that they give me different line
>> breaks even with the same source and tfms given. Last time I was
>> working on a Chinese translation of Karl's TeX for the Impatients, It
>> occured to me that LuaTeX's linebreak is so different from pdfTeX's,
>> and what's worse, LuaTeX gives me more overfull boxes. Of course, I
>> use an old version of LuaTeX distributed in TeXLive 2008 (0.25.x, if
>> memory serves). I doubt whether it will be possible for LuaTeX to
>> produce the similar result as TeX does, (not to say pixel level).
>
> we recenetly tested luatex (a more recent version than the one on tex
> live) with the texbook and there are only a few cases where we see
> differences, especially when ligatures occur at linebreaks; this is
> something that will be sorted out; 100% compatibility will never be
> reached because we use a slightly different route (separation of lig
> building, kerning, hyphenation and par building) but in practice this
> should not be a problem
>
> so, best use a recent version

I think that 0.25.x might have the big bad hyphenation bug.  However, I
suppose even when using a version where this has been sorted out, TeX's
behavior for things like shelf{}ful will not be imitated (in this case,
TeX separates the ligature unless it does a hyphenation pass on the
paragraph (can be forced with \pretolerance=-10000) in which case the
ligature will get recombined.  That's not something worth imitating.

-- 
David Kastrup