[TUHS] [groff] The hyphenation algorithm produces wrong results

Toby Thain toby at telegraphics.com.au
Mon Mar 5 07:32:02 AEST 2018


On 2018-03-04 4:00 PM, Bakul Shah wrote:
> 
> 
> On Mar 4, 2018, at 12:42 PM, Clem Cole <clemc at ccc.com
> <mailto:clemc at ccc.com>> wrote:
> 
>>
>> On Sun, Mar 4, 2018 at 3:23 PM, Doug McIlroy <doug at cs.dartmouth.edu
>> <mailto:doug at cs.dartmouth.edu>> wrote:
>>
>>
>>     I hadn't realized that groff hyphenation had been taken from
>>     Tex, not troff. Is that becuase Tex did a better job, or
>>     because troff's was deemed proprietary?
>>
>> Given the author, I would guess the later as he wanted to be FOSS and
>> would not have looked at the ditroff source - but that guess is worth
>> just that ;-)
> 
> I remembered reading about Knuth's line-breaking  algorithm in
> Software Practice & Experience in early eighties and being quite
> impressed with it. So may be that clear description of the algorithm
> has something to do with it? Ah, here it is:
> 
> “Breaking Paragraphs into lines” by Donald Knuth & Plass,
> SP&E, Volume 11, issue 11, Nov. 1981

That's the line breaker, which is an important contributor to the
quality of TeX output.

But TeX's *hyphenation* algorithm per se was invented by Franklin Mark
Liang and was indeed considerably better than its predecessors and
competitors (including most or all commercial typesetting software --
which was a big part of the motivation for it):

https://tug.org/docs/liang/liang-thesis.pdf

--Toby


> 
> (Download from Wiley is not free)
> 
> 
> 



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