Those questions were came up when I was looking through The TeXbook around page 225 and solving the exercise 21.6 in there:
In
\leaders
, are\vrule
and\hrule
essentially the same ? On the other word, what's difference between\vrule
and\hrule
in\leaders
?Why both
\vrule
and\hrule
can be used in\leaders
? I wonder it's restricted horizontal mode under\leaders
. Why both rules can be used in there. Is there any specific reason?
tex.pdf
the procedure for the output of a leader (§626) checksif type(leader_box) = rule_node then [...]
, so I'd guess that it doesn't distinguish hrule and vrule...tex.pdf
is new to me. What's that, and where can I find it?texdoc tex
opens that file. Otherwise, there's a copy intexdoc.net
. But apparently my guess was completely wrong :-)\showbox
. The more I think about it, the more I get confused why \rules are distinguished into \vrule and \hrule in general usage...