% Bugs (sigh) in The TeXbook

\input manmac
\proofmodefalse
\raggedbottom
\output{\onepageout{\unvbox255\kern-\dimen@ \vfil}}

\def\rhead{Bugs in {\sl The \TeX book}, first printing}
\def\bugonpage#1(#2) \par{\bigbreak\tenpoint
  \hrule\line{\lower3.5pt\vbox to13pt{}Page #1\hfil(#2)}\hrule\nobreak\medskip}

\noindent This is a list of all corrections made to {\sl The \TeX book\/}
between the first and second printings. If your copy says `{\sl\kern-1pt Second
printing (March 1984)\/}' on the copyright page, you've already got
all of these things corrected. Otherwise, you're a lucky owner of the
rare first edition; read on.

\bugonpage 63, seven lines below the first illustration (2/27/84)

\tenpoint
\line{points, a width of 5.5555 points, and a depth of zero;
the letter `g' has a height}

\bugonpage 72, line 35 (2/28/84)

\ninepoint\noindent
from |0pt|, but |0.00001filll| is infinitely greater than |16383.99999fill|.

\bugonpage 79, line 12 (2/28/84)

\ninepoint\indent
|\hbox(6.25+1.94444)x312.0, glue set 0.5783, shifted 36.0 []|

\bugonpage 101, lines 29--30 (3/13/84)

{\parfillskip=0pt
\danger It's possible to control the length of lines in a much more general
way, if simple changes to |\leftskip| and |\rightskip| aren't
flexible enough for your\par}

\bugonpage 113, bottom two lines (3/13/84)

{\parfillskip=0pt
\ddanger Notice that the first ``|%| line'' of our example says |t=10.0|;
this is a consequence of another parameter, called ^|\topskip|. Glue
disappears at a page break, but\par}

\bugonpage 131, display in exercise 16.8 (3/16/84)

\tenpoint\indent
|If$ x = y$, then $x$ is equal to $y.$|

\bugonpage 170, table in middle of the page (2/12/84)

\ninepoint
$$\baselineskip0pt\lineskip0pt
\halign to\hsize
 {\strut\hbox to\parindent{\it#\hfil}& % for the legend "Left atom"
  #\hfil\quad& % for the row labels
  #\hfil\tabskip 0pt plus 10pt& % for the rule at the left
  \hbox to 25pt{\tt\hss#\hss}& % for column 1
  \hbox to 25pt{\tt\hss#\hss}& % for column 2
  \hbox to 25pt{\tt\hss#\hss}& % for column 3
  \hbox to 25pt{\tt\hss#\hss}& % for column 4
  \hbox to 25pt{\tt\hss#\hss}& % for column 5
  \hbox to 25pt{\tt\hss#\hss}& % for column 6
  \hbox to 25pt{\tt\hss#\hss}& % for column 7
  \hbox to 25pt{\tt\hss#\hss}& % for column 8
  #\hfil\tabskip0pt\cr % for the rule at the right
\noalign{\vskip-6pt} % it just happens that there's extra white space
&&&&\multispan7\hss\it Right atom\hss\cr
\noalign{\vskip3pt}
&&&\rm Ord&\rm Op&\rm Bin&\rm Rel&\rm Open&\rm Close&\rm Punct&\rm Inner\cr
\noalign{\vskip2pt}
\omit&&\multispan{10}\leaders\hrule\hfil\cr
\omit\vbox to 2pt{}&&\vrule&&&&&&&&&\vrule\cr
&Ord&\vrule&0&1&(2)&(3)&0&0&0&(1)&\vrule\cr
&Op&\vrule&1&1&*&(3)&0&0&0&(1)&\vrule\cr
&Bin&\vrule&(2)&(2)&*&*&(2)&*&*&(2)&\vrule\cr
Left&Rel&\vrule&(3)&(3)&*&0&(3)&0&0&(3)&\vrule\cr
atom&Open&\vrule&0&0&*&0&0&0&0&0&\vrule\cr
&Close&\vrule&0&1&(2)&(3)&0&0&0&(1)&\vrule\cr
&Punct&\vrule&(1)&(1)&*&(1)&(1)&(1)&(1)&(1)&\vrule\cr
&Inner&\vrule&(1)&1&(2)&(3)&(1)&0&(1)&(1)&\vrule\cr
\omit\vbox to 2pt{}&&\vrule&&&&&&&&&\vrule\cr
\omit&&\multispan{10}\leaders\hrule\hfil\cr}$$

\bugonpage 173, line 11 (1/2/84)

\indent|Clearly $a_i<b_i$ for~$i=1, 2, \ldots, n$.|

\bugonpage 189, line 18 (2/13/84)

\ninepoint\noindent
{\parfillskip=0pt
when there is an overlap.] \ If $e=0$ and if there is an |\leqno|,
the equation number is\par}

\bugonpage 204, line 31 (2/13/84)

\ninepoint\noindent
of\/ |\a| is delimited by a left brace.

\bugonpage 219, simplification of line 18 (2/15/84)

\ninepoint\indent
|  \advance\count0 by\count2 \hexdigit}}|

\bugonpage 223, lines 3--4 (3/13/84)

{\parfillskip=0pt
\ddanger Chapters 24 to 26 present summaries of all \TeX's operations
in all modes, and when those summaries mention a `\<box>' they mean one
of the seven\par}

\bugonpage 242, line 29 (1/2/84)

\ninepoint\noindent
{\parfillskip=0pt
a relation, the solution is to insert `|{}|' ^^{lbrace rbrace}
at the beginning of the right-hand formula; \TeX
\par}

\bugonpage 245, line 24 (2/15/84)

\ninepoint\noindent
of a box that spans columns $i$ through~$j$,
hence the glue in such a box might shrink.

\bugonpage 248, the fourth dangerous bend (2/15/84)

{\parfillskip=0pt
\ddanger You have to be careful with the use of |&| and ^|\span| and ^|\cr|,
because these tokens are intercepted by \TeX's scanner even when it is
not expanding macros.\par}

\bugonpage 249, lines 20--26 (2/15/84)

\ninepoint\noindent
line (see Chapter~9).
If you don't want a~|\cr| at the end of a certain line,
just type `|%|' and the corresponding |\cr|
will be ``commented out.'' ^^{percent} \ (This special mode doesn't
work with ^|\+| lines, since |\+| is a macro whose argument is delimited
by the token `|\cr|', not simply by a token that has the same meaning
as~|\cr|.  ^^{delimited arguments} But you can redefine |\+| to overcome
this hurdle, if you want to. For example, define a macro |\alternateplus|
that is just like |\+| except that its argument is delimited by the active
character |^^M|; then include the command `|\let\+=\alternateplus|' as
part of\/ |\obeylines|.)

\bugonpage 254, lines 1--13 (3/13/84)

\ddanger \TeX's primitive command |\shipout|\<box> is what actually
causes output. It sends the contents of the box to the |dvi| file,
which is \TeX's main output file; after \TeX\ has finished,
the ^|dvi| file will contain a compact device-independent encoding of
instructions that specify exactly what should be printed.  When a
box is shipped out, \TeX\ displays the values of\/ |\count0| through
|\count9| on your terminal, ^^|\count0| as explained in Chapter~15; these
ten counters are also recorded in the |dvi| file, where they can be used
to identify the page. All of the ^|\openout|, ^|\closeout|, and ^|\write|
commands that appear inside of the \<box> are performed in their natural
order as that box is being shipped out. Since a |\write| command
expands macros, as explained in Chapter~21, \TeX's scanning mechanism
might detect syntax errors while a |\shipout| is in progress. If
^|\tracingoutput| is nonzero at the time of a |\shipout|, the contents
of the \<box> being shipped are written into your log file in symbolic
form. You can say |\shipout| anywhere, not only in an output routine.


\bugonpage 256, starting with line $-17$ (11/1/83)

\ninepoint
\textindent{6)} Finally, the ^|\dosupereject| macro is designed to clear
out any insertions that have been held over, whether they are illustrations
or footnotes or both: ^^|\insertpenalties| ^^|\supereject|
\begintt
\ifnum\insertpenalties>0
  \line{} \kern-\topskip \nobreak
  \vfill\supereject\fi
\endtt
The mysterious negative ^|\kern| here cancels out the natural space of the
^|\topskip| glue that goes above the empty |\line|; that empty line box
prevents the ^|\vfill| from disappearing into a page break.  The vertical
list that results from |\dosupereject| is placed on \TeX's list of things
to put out next, just after the straggling insertions have been
reconsidered as explained in Chapter~15. Hence another super-eject will
occur, and the process will continue until no insertions remain.

\bugonpage 262, line 14 (2/12/84)

\ninepoint\indent
|\def\endindex{\mark{}\break\endgroup}|

\bugonpage 262, lines 34 and 35 (2/12/84)

\ninepoint\noindent
if\/ |\next| is `|\endindex|',
the next commands executed will be `|\vfill|\allowbreak
|\mark{}|\allowbreak|\break|\allowbreak|\endgroup|';
otherwise the line will be treated as a main entry.

\bugonpage 274, line 24 (2/15/84)

\ninepoint\indent
|\lineskip|\quad(interline glue if\/ |\baselineskip| isn't feasible)

\bugonpage 289, slight clarification on lines 39--41 (3/10/84)

\ninepoint
A \<math character> defines a 15-bit number either by specifying it
directly with ^|\mathchar| or in a previous ^|\mathchardef|, or by
specifying a 27-bit |\delimiter| value; in the latter case, the least
significant 12~bits are discarded.


\bugonpage 307, a slightly more explicit answer (11/3/83)

\ninepoint\noindent
\hbox to\parindent{\bf\hss6.3.\enspace}%
It represents the heavy bar that shows up in
your output. \ (This bar wouldn't be present if\/ ^|\overfullrule| had been
set to |0pt|, nor is it present in an underfull box.)

\bugonpage 313, first four lines (3/13/84)

{\ninepoint\parfillskip=0pt
\ansno12.17:
 You get `A' at the extreme left and `puzzle.\null' at the extreme right,
because the space between words has the only stretchability that is finite;
the infinite stretchability cancels out. \ (In this case, \TeX's rule
about ^{infinite glue} differs from what you would get in the limit if the
value of $1\,{\rm fil}$ were finite but getting larger and larger.
The true\par}

\bugonpage 315, first three lines (3/13/84)

\ninepoint
\ansno14.14:
 Just say |\parfillskip|\stretch|=|\stretch|\parindent|. Of course,
\TeX\ will not be able to find appropriate line breaks unless each
paragraph is sufficiently long or sufficiently lucky; but with an
appropriate text, your output will be immaculately
symmetrical.{\parfillskip=\parindent\par}

\bugonpage 324, line 16 (2/15/84)

\ninepoint\noindent
\hbox to\parindent{\bf\hss18.41.\enspace}%
|$$\{\underbrace{\overbrace{\mathstrut a,\ldots,a}|

\bugonpage 333, beginning of the final paragraph (12/19/83)

\ninepoint
{\sl Note:\/} The stated preamble solves the problem and demonstrates
that \TeX's line-breaking capability can be used within tables. But this
particular table is not really a good example of the use of\/ |\halign|,
because \TeX\ could typeset it directly, using ^|\everypar| in an
appropriate manner to set up the hanging indentation, and using |\par|
instead of\/ |\cr|. For example, one could say

\bugonpage 341, the bottom line was left out! (2/9/84)

\tenpoint\line{Footline\quad\dotfill\quad Page 1009}

\bugonpage 345, top three lines (1/26/84)

\ninepoint{\noindent\parfillskip=0pt
A mathcode is relevant only when the corresponding category code is
11 or~12; therefore many of these codes will rarely be looked at. For
example, the math code for |^^M| specifies the character |\oplus|,
but it's hard to imagine a user who would want |^^M|\par}

\bugonpage 345, line 31 (2/29/84)

\ninepoint\noindent
|\delcode`\<="26830A    \delcode`\\="26E30F    \delcode`\>="26930B|

\bugonpage 347, lines 1 and 2 (3/16/84)

\ninepoint\noindent
|\count18=3  % this counter allocates math families 4, 5, 6, ...|\hfil\break
|\count19=255 % this counter allocates insertions 254, 253, 252, ...|

\bugonpage 350, line 9 from the bottom (3/16/84)

\ninepoint\noindent
font, whose information does not have to be loaded again.

\bugonpage 359, starting with line 2 (11/16/83)

\ninepoint
\beginlines
|\mathchardef\ldotp="602E\mathchardef\cdotp="6201\mathchardef\colon="603A|
|\def\ldots{\mathinner{\ldotp\ldotp\ldotp}}|
|\def\cdots{\mathinner{\cdotp\cdotp\cdotp}}|
|\def\vdots{\vbox{\baselineskip=4pt \lineskiplimit=0pt|
|    \kern6pt \hbox{.}\hbox{.}\hbox{.}}}|
|\def\ddots{\mathinner{\mskip1mu\raise7pt\vbox{\kern7pt\hbox{.}}\mskip2mu|
|    \raise4pt\hbox{.}\mskip2mu\raise1pt\hbox{.}\mskip1mu}}|
\endlines

\bugonpage 359, starting with line 19 (11/3/83)

{\ninepoint\parindent=0pt
|\def|^|\overbrace|%
  |#1{\mathop{\vbox{\ialign{##\crcr\noalign{\kern3pt}|\parbreak%
|     \downbracefill\crcr\noalign{\kern3pt\nointerlineskip}|\parbreak%
|     $\hfil\displaystyle{#1}\hfil$\crcr}}}|^|\limits||}|

|\def|^|\underbrace||#1{\mathop{\vtop{\ialign{##\crcr|\parbreak%
|     $\hfil\displaystyle{#1}\hfil$\crcr|%
  |\noalign{\kern3pt\nointerlineskip}|\parbreak%
|     \upbracefill\crcr\noalign{\kern3pt}}}}\limits}|
}

\bugonpage 359, seventh line from the bottom (2/29/84)

\ninepoint\noindent
|\def\backslash{\delimiter"026E30F }   \def\bracevert{\delimiter"000033E }|

\bugonpage 364, starting with line 10 (11/1/83)

{\ninepoint\parindent=0pt
|\def\dosupereject{\ifnum\insertpenalties>0 % something is being held over|%
\parbreak
|  \line{}\kern-\topskip\nobreak\vfill\supereject\fi}|
}

\bugonpage 370, line 7 (3/16/84)

\ninepoint\noindent
information about the \TeX\ Users Group.)

\bugonpage 379, line 1 (1/12/84)

\ninepoint\noindent
A particular item can be selected by its position number from the left:

\bugonpage 381, line 6 (2/12/84)

\ninepoint\indent
|\newcount\lineno % the number of file lines listed|

\bugonpage 381, lines 24 and 25 (12/15/83)

\ninepoint
{\parfillskip=0pt
Instead of listing a file verbatim, you might want to define a |\verbatim|
macro such that `|\verbatim{$this$|{\tt\ is }|{\it!}}|' yields
`|$this$|{\tt\ is }|{\it!}|'. It's somewhat\par}

\bugonpage 385, lines 22 and 23 (1/12/84)

\ninepoint\noindent
macro, a parameter, or a token list
variable; (b)~when \TeX\ must determine whether the token
|&|~or ^|\span| ^^{ampersand}
or ^|\cr| or~^|\crcr| is the end of an entry within an ^{alignment}.

\bugonpage 387, two paragraphs in right column (1/18/84)

\setbox0=\vbox{
\eightpoint
\tolerance=9999
\hbadness=2300
\finalhyphendemerits=3000000
\doublehyphendemerits=1000000
\parskip=1pt
\parindent=1.5em
\frenchspacing
\hsize=166.8125pt
\def\\#1{\raise.5pt\hbox{$\scriptscriptstyle
    \ifx#1`\langle\!\langle\else\rangle\!\rangle\fi$}% Spanish quote marks
  \ifx#1`\nobreak\hskip0pt \fi} % allow hyphenation
\item{A.} Exactamente. Pero los profesores son tan conservadores
que temer\'\i an espantar al tipo de estudiante \\`apisonadora\\'
que hace lo que le proponen para casa, obe\-dien\-te\-mente y de forma
mec\'anica. Adem\'as, no creo que les gustase el trabajo adicional
de calificar respuestas a preguntas abiertas.

\item{}La forma tradicional es dejar la parte creativa para los cursos
altos. Durante diecisiete a\~nos o m\'as se ense\~na al es\-tu\-diante a
aprobar, luego de golpe, cerca de la graduaci\'on, se le pide que haga
algo original.

}\rightline{\box0}

\bugonpage 395, lines 21 and 22 (1/12/84)

\ninepoint\noindent
{\parfillskip=0pt
Notice that the macros need to do their own checking for ligatures, and
they also take appropriate actions when a paragraph begins with an opening
quote.  Since |\kern|\par}

\bugonpage 399, line 1 (1/10/84)

\ninepoint
{\parfillskip=0pt
Inside the output routine, |\box\footins| will now be a vbox of hboxes, and
\par}

\bugonpage 399, line 9 (2/28/84)

\ninepoint\indent
|.\hbox(7.6359+0.0)x269.62617 []|

\bugonpage 408, line 15 (12/14/83)

\noindent
|    P. O. Box 1009, Haga Alto, CA 94321 USA}|

\smallskip\noindent\ninepoint
[Also change the ZIP code in the return address on the envelope
illustrated at the bottom of page 405.]

\bugonpage 409, line 5 (2/18/84)

\ninepoint\noindent
|\font\twelveit=cmti10 at 12pt  % (a cheap substitute for cmti12)|

\bugonpage 422, lines 24--26 (2/9/84)

\ninepoint\noindent
(The last two lines use |\d@nger| and |\dd@nger|, which are non-|\outer|
equivalents of\/ |\danger| and |\ddanger|; such duplication is necessary
because control sequences of type ^|\outer| cannot appear within a |\def|.)

\bugonpage 428, in the table of sixteen basic fonts (12/19/83)

\ninepoint\noindent
[The special fonts called |cmi10| and |cmi7| and |cmi5| should really be
called |cmmi10| and |cmmi7| and |cmmi5|.]

\bugonpage 445, line 6 (11/11/83)

\ninepoint
\line{if $(a-{1\over2}\theta)-
\bigl(h(z)-v\bigr)<\varphi$, increase~$v$ by the difference. Finally
construct a vbox of}

\bugonpage 449, line 12 (1/18/84)

\line{immediately clear why the `n' should
be attached to the `e' in one case but not}

\bugonpage 459, left column, line 2 (1/18/84)

\eightpoint
al-Khw\^arizm\^\i, abu Ja`far Mu\d{h}ammad

\bugonpage 462, index entry for {\tt\char`\\colon} (11/16/83)

\ninepoint Add page \underbar{359} to this list.

\bugonpage 464, index entry for {\tt\char`\\dump} (1/10/84)

\ninepoint Add page {\it 344\/} to this list.

\bugonpage 464, right column, line 5 (1/5/84)

\eightpoint
Dvo\v r\'ak, Anton\'\i n Leopold, 409.

\bugonpage 469, index entry for {\tt\char`\\kern} (11/1/83)

\ninepoint Add page {\it 256\/} to this list.

\bugonpage 470, index entry for {\tt\char`\\limits} (11/3/83)

\ninepoint Add page {\it 359\/} to this list.

\bugonpage 472, right column, line 28 (1/3/84)

\eightpoint\indent
\hbox to0pt{\hss\lower1pt\hbox{*}}|\nullfont|, 14, 153, 271, 433.

\bugonpage 479, index entry for {\tt\char`\\tracingoutput} (3/13/84)

\ninepoint Add page 254 to this list.

\bugonpage 480, index entry for {\tt\char`\\vbox} (11/1/83)

\ninepoint Delete page 256 from this list.

\bye