[tex-hyphen] String preparation

[Hans Hagen]

On 5/26/2016 8:59 AM, Élie Roux wrote:

> How do you foresee an implementation for this? This has to be in the
> engine right? And how would you specify that? With a new primitive, or a
> new symbol in the patterns (œ, )?

the problem with that is that we get a more and more complex routine 
which degrades performance, makes it hard to configure and explain, even 
not intuitive

anyway, because in a glyph the left/right fields store the current 
values of left and right hyphenmin it's not too hard to run over the 
list using a callback and adapt that value (the first one in a word)

- identify start of word
- look at left value of the first glyph
- see if there is a char in the #left glyphs that you want to count more 
or less times
- and adapt the left value accordingly

something like that perfectly fits in the concept of luatex: extending 
or manipulating existing (simple) mechanisms via callbacks

Hans


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