🚀 go-pugleaf

I'm using the ".hw" command with DWB 2.0 ditroff to specify
hyphenation exceptions.  (Yes, I know the hyphenation exception
list is normally limited to 128 characters, but I've compiled our
ditroff with a much larger value.  Yes, I also know that ditroff
uses a slow linear search through this list.)  I think I've found a
bug with ditroff's handling of the exception list.  If the word
going into the exception list has a ligature in it, the word
is never found in the exception list.  For example, if you say

	.hw spec-i-fi-ca-tion

the "fi" ligature screws up ditroff so that it doesn't recognize
the word "specification" in its exception list, and it hyphenates
the word between the "f" and the "i", which is incorrect.  The only
way around this appears to modify the actual document so that the
word appears as "spec\%i\%fi\%ca\%tion".  Has anyone seen this
before ?

Also, has anyone ever used the undocumented ".ht" command, which sets
the "digram goodness threshold" value ?  Does it help troff's
poor hyphenation ?

	Richard Stevens
	Health Systems International, New Haven, CT
	   stevens@hsi.com
           ... { uunet | yale } ! hsi ! stevens