5

Is the discretionary of the word difficult di\discretionary{f-}{fi}{ffi}cult equivalent to dif\-ficult (or dif\discretionary{-}{}{})?

1
  • 3
    Instead of dif\-ficult it's better to use \hyphenation{dif-ficult}. Putting the discretionary by hand will break the ffi ligature (which is probably why you are asking this question). May 13 at 16:45

1 Answer 1

8

The TeXbook, p. 95

The most common case of a discretionary break is a simple discretionary hyphen

\discretionary{-}{}{}

for which TeX accepts the abbreviation \-.

Hence dif\-ficult is equivalent to dif\discretionary{-}{}{}ficult.


You can also see this in the output log:

\showboxbreadth=\maxdimen
\showboxdepth=\maxdimen
\setbox0\hbox{dif\-ficult}
\showbox0
\bye
> \box0=
\hbox(6.94444+0.0)x33.6112
.\tenrm d
.\tenrm i
.\tenrm f
.\discretionary
..\tenrm -
.\tenrm ^^L (ligature fi)
.\tenrm c
.\tenrm u
.\tenrm l
.\tenrm t

The other variant with di\discretionary{f-}{fi}{ffi}cult produces

> \box0=
\hbox(6.94444+0.0)x33.33342
.\tenrm d
.\tenrm i
.\discretionary replacing 1
..\tenrm f
..\tenrm -
.|\tenrm ^^L (ligature fi)
.\tenrm ^^N (ligature ffi)
.\tenrm c
.\tenrm u
.\tenrm l
.\tenrm t
1
  • 1
    Thanks. I misunderstood \discretionary. They are different, the positions of line breaks in these two cases are also different (if the line breaks at the position \discretionary appears).
    – Lucas
    May 14 at 3:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.