[Dev-luatex] Trouble with hyphenation.

Hans Hagen pragma at wxs.nl
Sun Feb 19 11:45:49 CET 2012

```On 19-2-2012 07:25, Paul Isambert wrote:

>> luatex hyphenates the whole list in one go and does not do this delayed
>> and partial as in traditional tex ... this is on purpose as it provides
>> callback code with the whole lot (in luatex the hyphenation / ligature
>> building and justification steps are separated) ... also, there is no
>> reason not to hyphenate the first word if you have real narrow columns.
>
> I agree, it's just that TeX3 does otherwise.

btw, similar differences in engines can be found in ligature de/re
composition where tex3 does some juggling that luatex doesn't (for good
reason)

> The parameters are obeyed in all other engines, exception or not; I
> suppose the reason is that they may very well change in the course of
> the document.

Ok, but as luatex can have more advanced content in \hyphenation it is
more tricky (and probably costly) to have dynamic adaption to those min
values so I wonder if it's worth the trouble.

> But actually I've just found things are a little bit more complicated:
> LuaTeX doesn't hyphenate a word if it is shorter than \lefthyphenmin +
> \righthyphenmin (which makes sense); but if the word is hyphenated, and
> it is an exception, then it gets hyphens everywhere, whatever the values
> of the parameters:

ok, that's weird indeed and could qualify as a bug

Hans

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