[tex-k] ligatures and explicit kerns
karl at freefriends.org
Fri Oct 3 01:48:25 CEST 2014
ligatures won't be inserted in words that do contain explicit kerns.
It would be unexpected, at least by me, for a kern in one position
within a word to disable ligatures everywhere within the word, not just
at the point of the kern. I agree that the text you quoted can be read
that way; repeating it here:
Appendix H points out that ligatures are put into a hyphenated
word that contains no ``explicit kerns,'' and an italic correction
is an explicit kern.
but I would suggest interpreting it as a more limited statement:
ligatures are avoided at the point of the explicit kern. (After all, TB
is not intended to be a legal document.) At most there might be a
clearer statement in TB, if you want to make a report for DEK's
consideration; obviously the actual behavior is not going to be changed.
I didn't find the place in appendix H the quote refers to, so
pointers would be appreciated.
I do not see a single "place" that is being referred to; as far as I can
tell, it's rather a consequence of all the multifarious rules in App. H.
(But maybe I'm missing it, I did not reread every word [again].)
Perhaps the most direct statement is this one, talking about what
"hyphenating a word" actually means (namely, inserting discretionaries):
\ddanger Trial words ...
If other hyphenation points are found, one or more discretionary items
are inserted in the word; ligatures and implicit kerns are reconstituted
at the same time.
The first statement is a negative construction, the second a positive
one. Always tricky to compare.
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