path: root/systems/knuth/dist/errata/errata.tex

% Bugs (sigh) in Computers \& Typesetting --- the most recent errata

\tracingpages=1
\input manmac
\def\.#1{\hbox{\tt#1}}
\font\sltt=cmsltt10
\font\niness=cmss9
\font\ninessi=cmssi9
\proofmodefalse
\raggedbottom
\output{\hsize=29pc \onepageout{\unvbox255\kern-\dimen@ \vfil}}

\def\today{\number\day\
  \ifcase\month\or
  Jan\or Feb\or Mar\or Apr\or May\or Jun\or
  Jul\or Aug\or Sep\or Oct\or Nov\or Dec\fi
  \ \number\year}

\def\cutpar{{\parfillskip=0pt\endgraf}}

\def\rhead{Bugs in {\tensl Computers \& Typesetting as of \today}}
\def\bugonpage#1(#2) \par{\bigbreak\tenpoint
  \hrule width\hsize
  \line{\lower3.5pt\vbox to13pt{}Page #1\hfil(#2)}\hrule width\hsize
  \nobreak\medskip}
\def\buginvol#1(#2) \par{\bigbreak\penalty-1000\tenpoint
  \hrule width\hsize
  \line{\lower3.5pt\vbox to13pt{}Volume #1\hfil(#2)}\hrule width\hsize
  \nobreak\medskip}
\def\slMF{{\manual 89:;}\-{\manual <=>:}} % slant the logo
\def\0{\raise.7ex\hbox{$\scriptstyle\#$}}
\newcount\nn
\newdimen\nsize \newdimen\msize \newdimen\ninept \ninept=9pt
\newbox\eqbox \setbox\eqbox=\hbox{\kern2pt\eightrm=\kern2pt}

\tenpoint
\noindent This is a list of all substantial corrections made to {\sl Computers
\& Typesetting\/} since the beginning of 2014.
(More precisely, it lists errors corrected
since the 19th printing of Volume~A, the 9th printing
of Volume~B, the 8th printing of Volume~C, the 6th printing of Volume~D,
and the 7th printing of Volume~E. % 2012 for A-D, 2013 for E
But it omits changes that are ``purely cosmetic.'')
Corrections made to the softcover version of {\sl The \TeX book\/},
beginning with its 32nd printing, are
the same as corrections to Volume~A\null. Corrections to the softcover
version of {\sl The \slMF\kern1ptbook}, beginning with its 11th printing,
are the same as corrections to Volume~C\null. Changes to the mini-indexes
and master indexes of Volumes B, D, and~E are not shown here unless they are
not obviously derivable from what has been shown. Some (or all) of these
errors have been corrected in the most recent printings.
\looseness=-1

% volume A

\bugonpage A34, line 3 from the bottom (01/09/20)

\ninepoint\noindent
not, you can say
`\.{I\char`\\errorcontextlines=100} \.{\char`\\oops}' and try again. \ (That
will usually\cutpar

\bugonpage A43, line 6 (07/24/14)

\tenpoint\noindent
keyboard, or that have been
pre\"empted for formatting?

\bugonpage A49, cummings quote (08/03/19)

(delete the period at the end of the line)

\bugonpage A66, line 3 from the bottom (08/26/17)

\ninepoint
Such displays of box contents will be discussed further in
Chapters 12 and~27.\cutpar

\bugonpage A105, lines 9--16 (01/16/21)

\ddanger If you say \.{\char`\\vadjust\char`\{}$\langle\,$vertical
mode material$\,\rangle$\.{\char`\}} within a
paragraph, \TeX\ will use internal vertical mode to insert the specified
material into the vertical
list that encloses the paragraph, immediately after whatever line
contained the position of the \.{\char`\\vadjust}. For example, you can say
`\.{\char`\\vadjust\char`\{\char`\\kern1pt\char`\}}'
to increase the amount of space between lines of a
paragraph if those lines would otherwise come out too close together.  \ (The
\vadjust{\kern1pt}author
did that in the current line, just to illustrate what happens.) \ Also,
if you want to make sure that a page break will occur immediately after a
certain line, you can say `\.{\char`\\vadjust\char`\{\char`\\eject\char`\}}'
anywhere in that line.

\bugonpage A122, lines 3--8 (11/24/19)

\ninepoint\noindent
\.{\char`\\count255}, \.{\char`\\dimen255}, \.{\char`\\skip255},
\.{\char`\\muskip255}, and \.{\char`\\toks255} are
traditionally kept available for such purposes.  Furthermore, plain \TeX\
reserves \.{\char`\\dimen0} to \.{\char`\\dimen9},
\.{\char`\\skip0} to \.{\char`\\skip9}, \.{\char`\\muskip0} to
\.{\char`\\muskip9}, and \.{\char`\\box0} to \.{\char`\\box9}
for ``scratchwork''; these registers
are never allocated by the \.{\char`\\new...}\null\ operations.  We have seen that
\.{\char`\\count0} through \.{\char`\\count9} are special,
and \.{\char`\\box255} also turns out to
be special; so those registers should be avoided unless you know what you
are doing.

\bugonpage A155, line 8 from the bottom (01/17/21)

\ninepoint\indent
\.{\char`\\mathopen\char`\{\char`\\hbox\char`\{\char`\$\char`\\left\char`\#1}%
$\langle\,$strut$\,\rangle$\.{\char`\\right.\char`\$\char`\}\char`\}}

\bugonpage A155, the bottom six lines (12/10/18)

\ninepoint\noindent
dividual symbols; \.{\char`\\left}$\,\ldots\,$\.{\char`\\right}
constructions are treated as ``inner'' subformulas, which means that
they will be surrounded by additional space in certain circumstances.
All other subformulas are generally treated as ordinary symbols,
whether they are formed by \.{\char`\\overline} or
\.{\char`\\hbox} or \.{\char`\\vcenter} or
by simply being enclosed in braces. Thus, \.{\char`\\mathord} isn't really
a necessary part of the \TeX\ language; instead of typing
`\.{\char`\$1\char`\\mathord,234\char`\$}' you can get the same
effect from `\.{\char`\$1\char`\{,\char`\}234\char`\$}'.

\bugonpage A158, line 19 (12/10/18)

\ninepoint\indent
Inner\quad is an inner atom produced by
 `\.{\char`\\left}$\,\ldots\,$\.{\char`\\right}';

\bugonpage A170, lines 18 and 19 (12/10/18)

\ninepoint\noindent
subformulas delimited by \.{\char`\\left} and \.{\char`\\right}
are treated as type~Inner. The following table is
used to determine the spacing between pairs of adjacent atoms:

\bugonpage A171, line 19 from the bottom (06/15/19)

\ninepoint\noindent
formula produces a result essentially equivalent to
`\.{\char`\\left(}$\langle\,$subformula$\,\rangle$\.{\char`\\right)}',
when\cutpar

\bugonpage A215, line 16 from the bottom becomes two lines (10/13/20)

\ninepoint
\item\bull Just after a token such as \.{\char`\$}$_3$
that begins math mode, to see if
another token of category 3 follows.

\bugonpage A222, lines 21--23 (01/16/21)

\ninepoint
\halign{\indent#\hfil&\quad(see Chapter #)\hfil\cr
\.{\char`\\hbox}$\langle\,$box specification$\,\rangle$%
 \.{\char`\{}$\langle\,$horizontal mode material$\,\rangle$\.{\char`\}}&12\cr
\.{\char`\\vbox}$\langle\,$box specification$\,\rangle$%
 \.{\char`\{}$\langle\,$vertical mode material$\,\rangle$\.{\char`\}}&12\cr
\.{\char`\\vtop}$\langle\,$box specification$\,\rangle$%
 \.{\char`\{}$\langle\,$vertical mode material$\,\rangle$\.{\char`\}}&12\cr
}

\bugonpage A222, lines 11--13 from the bottom (01/16/21)

\ninepoint\noindent
ter~15. The \.{\char`\\vsplit} operation
is also explained in Chapter~15. In math modes an additional
type of box is available:
\.{\char`\\vcenter}$\langle\,$box specification$\,\rangle$%
 \.{\char`\{}$\langle\,$vertical mode material$\,\rangle$\.{\char`\}}
(see Chapter~17).

\bugonpage A232, line 14 (01/10/21)

\ninepoint\noindent
tabs outside; `\.{\char`\\global\char`\\settabs}' will not do what
you might think it should.

\bugonpage A233, lines 3--5 (04/27/15)

\tenpoint\noindent
Only two tabs are set in this case, because only two \.{\char`\&}'s
appear in the sample line. \ (A sample line usually
ends with~\.{\char`\&\char`\\cr}, as it does here,
because text material between the last tab and \.{\char`\\cr}
isn't used for anything.)

\bugonpage A252, lines 5--7 (12/25/20)

\ninepoint\noindent
blank, and
the footline is normally a centered page number, but you can specify any
headline and footline that you want by changing the token lists
\.{\char`\\headline} and \.{\char`\\footline}. For example,

\bugonpage A253, lines 7--9 from the bottom (10/27/20)

\ninepoint\indent
\.{\char`\\everypar} or \.{\char`\\errhelp}, except that \TeX\
retains the begin-group symbol~`\.{\char`\{}' at the beginning
and the end-group symbol~`\.{\char`\}}' at the end. These
grouping characters
help to keep the output routine from interfering with what
\TeX\ was doing\cutpar

\bugonpage A256, line 19 (08/28/15)

\ninepoint\indent
\tt \char`\\baselineskip=24pt \char`\\lineskiplimit=0pt

\bugonpage A277, lines 9 and 10 from the bottom (08/26/17)

\ninepoint\indent
$\langle\,$hyphenation assignment$\,\rangle$\is
 \.{\char`\\hyphenation}$\langle\,$filler$\,\rangle$%
 \.{\char`\{}$\langle\,$hyphenations$\,\rangle$\.{\char`\}}\par
\qquad \alt \.{\char`\\patterns}$\langle\,$filler$\,\rangle$%
 \.{\char`\{}$\langle\,$patterns$\,\rangle$\.{\char`\}}

\bugonpage A286, bottom two lines {(and affecting the top lines
of page 287)} (08/26/17)

\ninepoint\noindent
stands for zero or more \<assignment>
commands other than \.{\char`\\setbox}, possibly with \<filler>.
If the assignments are not followed by a \<character>, where
\<character> stands\cutpar

\bugonpage A287, lines 11--17  (04/22/20)

\ninepoint
\textindent{$\bull$} \.{\char`\\discretionary}%
  \<disc text>\<disc text>\<disc text>.\enskip
A \<disc text> has the form
`\<filler>\.{\char`\{}\<horizontal mode material>\.{\char`\}}',
where the material is processed in restricted horizontal mode and
should contain only fixed-width things.
More precisely, the horizontal list formed by each
\<disc text> must consist only of characters, ligatures,
kerns, boxes, and rules; there should be no glue or penalty items, etc.
This command appends a discretionary item to the current list; see
Chapter~14 for the meaning of a discretionary item. The space factor is
not changed.

\bugonpage A292, lines 8--10 (04/22/20)

\ninepoint
\textindent{$\bull$} \.{\char`\\discretionary}%
  \<disc text>\<disc text>\<disc text>.\enskip
This command has the same effect as in horizontal mode (see Chapter~25), but the
third \<disc text> must produce an empty list.

\bugonpage A299, line 11 from the bottom (11/01/20)

\ninepoint\noindent
is corrupted or was prepared for a different version of \TeX.

\bugonpage A305, bottom line (06/30/20)

\ninepoint\indent
\tt \char`\\setbox0=\char`\\hbox\char`\{\char`\#1\char`\}%
\char`\\advance\char`\\dimen0 by -\char`\\wd0 \char`\}\rm.

\bugonpage A309, line 2 becomes two lines (12/06/20)

\ninepoint\noindent
represent text entered from the user's terminal, or with
`\.{<insert>}', when they
represent text inserted during error recovery).

\bugonpage A316, lines 17 and 18 from the bottom (09/03/15)

\ninepoint\noindent
(The next line must also not be too tall.)
Here \.{\char`\\specialstar} is a box of height zero and depth
\.{\char`\\strutdepth},
and it puts an asterisk in the left margin:

\bugonpage A320, lines 5--9 from the bottom (06/27/15)

\ninepoint\noindent
{\bf 17.21.}\enspace Assigning \.{\char`\\delcode\char`\`\char`\{} 
would not work to allow `\.{\char`\\left\char`\{}', because
the brace has category~1 and isn't a legal \<delim>.
Allowing brace delimiters would be a bad idea because it would
mess up other constructions, such as arguments to macros, and
components of alignments. Moreover, a user who
gets away with `\.{\char`\\left\char`\{}'
is likely to try also `\.{\char`\\bigl\char`\{}', which
fails miserably.

\bugonpage A326, line 12 (08/26/17)

\ninepoint\noindent
its natural width. The \.{\char`\\hbox} version also invokes
\.{\char`\\everyhbox} and \.{\char`\\everymath}.

\bugonpage A329, line 3 of answer 20.7 (05/15/19)

\ninepoint\noindent
the three tokens \.{!1}, \.{\char`\#2}, \.{[}$_1$; the
\<replacement text> consists of the six tokens
\.{\char`\{}$_1$, \.{\char`\#}$_6$,\cutpar

\bugonpage A329, line 6 of answer 20.7 (05/15/19)

\ninepoint\noindent
is otherwise irrelevant. Thus, `\.{\char`\\def\char`\\!!1\char`\#2\char
 `\#[\char`\{\char`\#\char`\#]!!\char`\#2]}'
would produce an essentially\cutpar

\bugonpage A329, line 5 from the bottom of answer 20.7 (05/15/19)

\ninepoint\indent
\.{!1<-x}

\bugonpage A329, bottom line of answer 20.7 (05/15/19)

\ninepoint\noindent
final parameter in the parameter text;
`\.{!1}' would have been rendered `\.{\char`\#1}'.

\bugonpage A332, lines 13 and 14 (08/26/17)

\ninepoint\noindent
{\bf 21.10.}\enspace If you say
`\.{\char`\{\char`\\let}\stretch
\.{\char`\\the=0\char`\\edef}\stretch
\.{\char`\\next}\stretch
\.{\char`\{\char`\\write}\stretch
\.{\char`\\cont}\stretch
\.{\char`\{}\<token list>\.{\char`\}\char`\}\char`\\next}\stretch
\.{\char`\}}',
the \.{\char`\\write} will be exercuted after
\.{\char`\\edef} expands everything except \.{\char`\\the}.

\bugonpage A332, bottom line (11/15/19)

\ninepoint\indent\quad
\tt \char`\\+\char`\&\char`\{\char`\\bf end\char`\};\char`\\cr \
 \char`\%\ note that the semicolon isn't bold

\bugonpage A342, lines 12 and 13 (08/14/20)

\tenpoint\noindent
of plain \TeX\ format; but some of them are primitive (built in),
such as `\.{\char`\\par}' (end of
paragraph), `\.{\char`\\noindent}' (beginning of
non-indented paragraph), and `\.{\char`\/}' (italic\cutpar

\bugonpage A345, lines 10--13 from the bottom (06/27/15)

\ninepoint\noindent
Braces are used for grouping, when supplying
arguments to macros; so they cannot also be used as math delimiters, or as
arguments to macros such as \.{\char`\\big}. (One could change their catcodes
to~12, and use some other pair of characters for grouping; but that
would not be plain \TeX.)

\bugonpage A346, lines 10--22 (11/24/19)

\ninepoint\noindent
number identification.) \ (2)~The registers
\.{\char`\\count255}, \.{\char`\\dimen255}, \.{\char`\\skip255},
\.{\char`\\toks255}, and \.{\char`\\muskip255}
are freely available in the same way.
\ (3)~All assignments to the scratch registers whose numbers are
1,~3, 5, 7, and~9 should be \.{\char`\\global}; all assignments to the
other scratch registers (0,~2, 4, 6, 8,~255) should be non-\.{\char`\\global}.
\ (This prevents the phenomenon of ``save stack buildup'' discussed
in Chapter~27.)
\ (4)~Furthermore, it's possible to
use any register in a group, if you ensure that \TeX's grouping
mechanism will restore the register when you're done with the group, and
if you are certain that other macros will not make global assignments
to that register when you need it. \ (5)~But when a register is used
by several macros, or over long spans of time, it should be allocated
by \.{\char`\\newcount}, \.{\char`\\newdimen}, \.{\char`\\newbox},
etc. \ (6)~Similar remarks
apply to input/output streams used by \.{\char`\\read} and \.{\char`\\write},
to math families used by \.{\char`\\fam}, to sets of hyphenation rules used by
\.{\char`\\language}, and to insertions (which require
\.{\char`\\box}, \.{\char`\\count}, \.{\char`\\dimen},
and \.{\char`\\skip} registers all having the
same number).\looseness=-1

\bugonpage A347, line 6 (06/30/20)

\ninepoint\noindent
\tt \char`\\def\char`\\wlog\char`\{\char`\\immediate\char`\\write-1 \char`\}
\ \char`\%\ this will write on log file (only)

\bugonpage A347, line 10 (11/24/19)

\ninepoint\noindent
\tt \char`\\outer\char`\\def\char`\\newmuskip\char`\{\char`\\alloc@3%
\char`\\muskip\char`\\muskipdef\char`\\@cclv\char`\}

\bugonpage A347, line 14 (11/24/19)

\ninepoint\noindent
\tt \char`\\outer\char`\\def\char`\\newtoks\char`\{\char`\\alloc@5%
\char`\\toks\char`\\toksdef\char`\\@cclv\char`\}

\bugonpage A350, lines 15 and 16 from the bottom (01/17/21)

\ninepoint\noindent
format; it shouldn't cost much for people to acquire all the
fonts of plain \TeX\ in addition to the ones that they really want. Second, it
is desirable on many computer systems to\cutpar

\bugonpage A364, line 5 from the bottom (01/14/21)

\ninepoint\noindent
\tt \char`\\def\char`\\fmtversion\char`\{3.1415926535\char`\} 
\ \char`\%\ identifies the current format

\bugonpage A370, lines 11 and 12 (08/26/17)

\ninepoint\noindent
close as possible to the ASCII conventions.
\ (b)~Make sure that codes \oct{041}--\oct{046}, \oct{060}--\oct{071},
\oct{136}, \oct{141}--\oct{146}, and \oct{160}--\oct{171} are present and that
each unrepresentable in-\cutpar

\bugonpage A373, lines 21 and 22 (01/17/21)

\ninepoint\noindent
and \.{\char`\\if...\char`\\fi}
tests, as well as special operations like \.{\char`\\the}
and \.{\char`\\input}, while the
latter category includes the primitive commands listed in Chapters~24--26.
The expansion of\cutpar

\bugonpage A375, bottom three lines (06/30/20)

\ninepoint\noindent
|$$\generaldisplay$$| to be invoked, with |\eq| defined to be $\alpha$.
Furthermore, when an equation number~$\beta$ is present, it should be stored
in |\eqn|, and the test |\ifeqno| should be true.
In such cases |\ifleqno| should distinguish |\leqno| from |\eqno|.
Here\cutpar

\bugonpage A398, lines 4 and 5 (08/26/17)

\ninepoint\indent
|\setbox2=\lastbox \setbox\footins=\vbox{\box2}|\par
\smallskip\noindent
since |\lastbox| will be the result of\/ |\rigidbalance|, which is an hbox.

\bugonpage A407, line 5 from the bottom (06/30/20)

\ninepoint\noindent\quad
|  \interlinepenalty5000\def\par{\endgraf\penalty5000 }}|

\bugonpage A413, line 11 from the bottom (05/14/19)

\ninepoint\indent
The computer file |texbook.tex| that generated {\sl The \TeX book\/} begins
with a\cutpar

\bugonpage A418, line 4 (05/14/19)

\ninepoint\noindent
\TeX\ commands
that look like this in the file |texbook.tex|:

\bugonpage A420, line 11 (06/30/20)

\ninepoint\noindent
|\def\bull{\vrule height.9ex width.8ex depth-.1ex \relax} % square bullet|

\bugonpage A423, line 16 (06/30/20)

\ninepoint\noindent
|  \vrule height6pt depth2pt width0pt \relax} % a strut for \insert\margin|

\bugonpage A445, lines 10--14 (12/10/18)

\ninepoint
\textindent{\bf 15e.} Enclose the vbox that was constructed in Rule 15c or 15d by
delimiters $(\lambda,\rho)$
whose height plus depth is at least $\sigma_{20}$, if $C>T$, and at
least $\sigma_{21}$ otherwise. Shift the delimiters up or down so that they are
vertically centered with respect to the axis. Replace the generalized
fraction by an Ord atom whose nucleus is the resulting sequence of three boxes
($\lambda$, vbox, $\rho$). Go to rule~19.

\bugonpage A446, the bottom three lines of Rule 19 become four lines (01/10/21)

\ninepoint\noindent
atom and the right boundary item to
a Close atom. The entire resulting list now becomes the nucleus of an
Inner atom. \ (All of the calculations in this step are done with
$C$ equal to the starting style of the math list; style items in the
middle of the list do not affect the style of the right boundary item.)

\bugonpage A454, lines 17 and 18 from the bottom (04/13/20)

\ninepoint\noindent
of the process; the trial word consists of all the letters found in admissible
items, up to a maximum of~63. Notice that all of these letters are in font~$f$.

\bugonpage A458 and following, selected amendments to the index (01/18/21)

\eightpoint
|[1]| (progress report), 23, $\underline{119}$.\par
|\aa| ( \aa\ ), {\it52}, $\underline{356}$.\par
|\AA| ( \AA\ ), {\it52}, $\underline{356}$.\par
\<disc text>, $\underline{287}$, 292.\par
\<general text>, $\underline{276}$, 279, 280.\par
\<horizontal mode material>, 278, 285, 287.\par
integral signs, {\sl see\/} |\int|, |\oint|, |\smallint|.\par
\<math mode material>, 287, 289--293.\par
|\null|, 311, {\it312}, {\it316}, {\it332}, {\it335}, $\underline{351}$, {\it354}, {\it360}--{\it362}, {\it419}.\par
|\o| ( \o\ ), {\it52}, $\underline{356}$.\par
|\O| ( \O\ ), {\it52}, $\underline{356}$.\par
programs, for computers, 38, 165, {\it234}.\par
repeating templates, {\sl see\/} periodic preambles.\par
replacement text, {\it200}--{\it204}, 212, 280, 300, 329.\par
right delimiters, {\sl see\/} closings.\par
struts, $\underline{82}$, 125, 131, 142, 155, 178, 245--247, 255, 329, 416, 422, 423.\par
\<vertical mode material>, 278, 280--282, 290.


% volume B
\def\\#1{\hbox{\it#1\/\kern.05em}} % italic type for identifiers
\def\dts{\mathrel{.\,.}} % double dot, used only in math mode

\bugonpage Bv {(formerly Bvii)}, bottom two lines (01/15/21)

\eightpoint\noindent
all of those changes.
I~now believe that the final bug was discovered on 22 October 2020
and removed in version 3.141592653. % on 12 January 2021
The finder's fee has converged to \$327.68.

\hsize=35pc

\bugonpage B2, line 10 from the bottom (01/15/21)

\ninepoint\noindent\hskip10pt
{\bf define} $\\{banner}\equiv\hbox{\tt\char'23}$%
{\tt This\]is\]TeX,\]Version\]3.141592653\char'23}\quad
$\{\,$printed when \TeX\ starts$\,\}$

\bugonpage B4, line 8 of \S7 (04/02/17)

\tenpoint\noindent
diagnostic information for \.{\char`\\tracingparagraphs},
\.{\char`\\tracingpages}, and \.{\char`\\tracingrestores}.

\bugonpage B21, lines 33 and 34 (04/02/17)

\def\Oct#1{\hbox{\rm\char'23\kern-.2em\it#1\/\kern.05em}} % octal constant
\tenpoint\noindent
$[\Oct{41}\to\Oct{46},\Oct{60}%
\to\Oct{71},\Oct{136},\Oct{141}\to\Oct{146},\Oct{160}\to\Oct{171}]$ must be printable.
Thus, at least 80 printable characters are needed.

\bugonpage B28, lines 3 and 4 (04/02/17)

\tenpoint\noindent
not serious since we assume that this
part of the program is system dependent.

\bugonpage B28, line 2 from the bottom (04/02/17)

\ninepoint\noindent\quad
{\bf var} $k$: $0\dts23$;\quad$\{\,$index to current digit; we assume
 that $\vert n\vert<10^{23}\,\}$

\bugonpage B35, line 2 of \S83 becomes two lines (06/27/20)

\ninepoint\noindent\quad
{\bf loop begin} \\{continue}: {\bf if} $\\{interaction}\ne\\{error\_stop\_mode}$
  {\bf then return};\par
\noindent\qquad
\\{clear\_for\_error\_prompt}; \ \\{prompt\_input}(\.{"?\]"});

\bugonpage B36, line 11 of \S84 (07/03/20)

\ninepoint\noindent\quad
\.{"E"}: {\bf if} $\\{base\_ptr}>0$ {\bf then if}
 $\\{input\_stack}[\\{base\_ptr}].\\{name\_field}\ge256$ {\bf then}

\bugonpage B36, line 5 of \S85 becomes two lines (07/03/20)

\ninepoint\noindent\quad
{\bf if} $\\{base\_ptr}>0$ {\bf then}\par
\noindent\qquad
{\bf if} $\\{input\_stack}[\\{base\_ptr}].\\{name\_field}\ge256$ {\bf then}
\\{print}(\.{"E\]to\]edit\]your\]file."}

\bugonpage B40, line 5 from the bottom (08/07/20)

\ninepoint\noindent\qquad
(\.{"Try\]to\]insert\]an\]instruction\]for\]me\](e.g.,\]%
        \char`\`I\char`\\showlists\char`\'),"})

\bugonpage B58, lines 2 and 3 of \S136 (10/11/20)

\tenpoint\noindent
the values corresponding to `\.{\char`\\hbox\char`\{\char`\}}'.
The \\{sub\_type} 
field is set to \\{min\_quarterword}, for historic reasons that are no
longer relevant.

\bugonpage B88, line 16 (10/22/20)

\tenpoint\noindent
The mode is temporarily set to zero while processing \.{\char`\\write} texts.

\bugonpage B102, lines 3 and following of \S241 (12/11/20)

\tenpoint\noindent
information, something special
is needed. The program here simply assumes that suitable values appear in
the global variables \\{sys\_time}, \\{sys\_day}, \\{sys\_month}, and
\\{sys\_year} (which are initialized to noon on 4 July 1776,
in case the implementor is careless).
\smallskip
\ninepoint\noindent
{\bf procedure} \\{fix\_date\_and\_time};\par
\noindent\quad{\bf begin}
$\\{sys\_time}\gets12\ast60$; \
$\\{sys\_day}\gets4$; \
$\\{sys\_month}\gets7$; \
$\\{sys\_year}\gets1776$;\quad
$\{\,$self-evident truths$\,\}$\par
\noindent\quad$\\{time}\gets\\{sys\_time}$;\quad
  $\{\,$minutes since midnight$\,\}$\par
\noindent\quad$\\{day}\gets\\{sys\_day}$;\quad$\{\,$day of the month$\,\}$\par
\noindent\quad$\\{month}\gets\\{sys\_month}$;\quad$\{\,$month of the year$\,\}$\par
\noindent\quad$\\{year}\gets\\{sys\_year}$;\quad$\{\,$Anno Domini$\,\}$\par
\noindent\quad{\bf end};

\bugonpage B103, replacement for \S246 (12/11/20)

\tenpoint\noindent
{\bf 246.}\quad Of course we had better declare a few more global variables,
if the previous routines are going to work.
\smallskip
\ninepoint\noindent
$\langle\,$Global variables {\sevenrm\kern.5em13}$\,\rangle+\equiv$\par
\noindent\\{old\_setting}: $0\dts\\{max\_selector}$;\par
\noindent\\{sys\_time}, \\{sys\_day}, \\{sys\_month}, \\{sys\_year}: \\{integer};
\quad$\{\,$date and time supplied by external system$\,\}$

\goodbreak
\bugonpage B122, lines 9 and 10 of \S291 (10/12/20)

\tenpoint\noindent\quad
The enclosing \.{\char'173} and \.{\char'175} characters of a macro
definition are omitted, but an output routine
will be enclosed in braces.

\bugonpage B143, lines 2, 3, 4 become four lines (01/15/17)

\tenpoint\noindent
routines that should be aborted, but we can sketch the
ideas here:  For a runaway definition or a runaway balanced text,
we will insert a right brace; for a
runaway preamble, we will insert a special \.{\char`\\cr} token and a right
brace; and for a runaway argument, we will set \\{long\_state} to
\\{outer\_call} and insert \.{\char`\\par}.

\bugonpage B188, line 8 (04/02/17)

\ninepoint\noindent
{\bf function} \\{str\_toks}$(b:\\{pool\_pointer})$: \\{pointer};\quad
 $\{\,$converts \\{str\_pool}$[b\dts\\{pool\_ptr}-1]$ to a token list$\,\}$

\bugonpage B192, line 17 (10/22/20)

\ninepoint\noindent\quad
{\bf label} \\{found}, \\{continue}, \\{done}, \\{done1}, \\{done2};

\bugonpage B192, line 3 of \S474 (10/22/20)

\ninepoint\noindent\qquad
{\bf begin} \\{continue}: \\{get\_token};\quad$\{\,$set \\{cur\_cmd},
  \\{cur\_chr}, \\{cur\_tok}$\,\}$

\bugonpage B193, line 4 of \S476 (05/20/20)

\ninepoint\noindent\quad
{\bf if} $\\{cur\_tok}<\\{left\_brace\_limit}$ {\bf then}

\bugonpage B193, line 10 of \S476 becomes two lines (10/22/20)

\ninepoint\noindent\qquad
\\{help2}(\.{"I\char`\'m\]going\]to\]ignore\]the\]\#\]sign\]you\]just\]used,"})\par
\noindent\qquad
(\.{"as\]well\]as\]the\]token\]that\]followed\]it."});
\\{error}; {\bf goto} \\{continue};

\bugonpage B196, line 5 from the bottom (02/17/18)

\ninepoint\noindent\qquad\quad
\\{help1}(\.{"This\]\char`\\read\]has\]unbalanced\]braces."});
$\\{align\_state}\gets1000000$;
$\\{limit}\gets0$;
\\{error};

\bugonpage B199, lines 1--3 of \S494 (10/25/20)

\tenpoint\noindent
{\bf 494.} \ \ Here is a procedure that ignores text until coming to an \.{\char`\\or},
\.{\char`\\else}, or \.{\char`\\fi} at the current level
of $\.{\char`\\if}\ldots\.{\char`\\fi}$
nesting. After it has acted, \\{cur\_chr} will indicate the token that
was found, but \\{cur\_tok} will not be set (because this makes the
procedure run faster).


\bugonpage B214, lines 2--6 of \S536 (12/11/20)

\ninepoint\noindent\quad
{\bf begin} \\{wlog}(\\{banner});
\\{slow\_print}(\\{format\_ident});
\\{print}(\.{"\]\]"});
\\{print\_int}(\\{sys\_day});
\\{print\_char}(\.{"\]"});\par
\noindent\quad
$\\{months}\gets\.{\char`\'JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC\char`\'}$;\par
\noindent\quad
{\bf for} $k\gets3\ast\\{sys\_month}-2$ {\bf to} $3\ast\\{sys\_month}$
{\bf do} \\{wlog}(\\{months}[$k$]);\par
\noindent\quad
\\{print\_char}(\.{"\]"});
\\{print\_int}(\\{sys\_year});
\\{print\_char}(\.{"\]"});
\\{print\_two}(\\{sys\_time} {\bf div} 60);
\\{print\_char}(\.{":"});\par
\noindent\quad
\\{print\_two}(\\{sys\_time} {\bf mod} 60);

\bugonpage B214, line 2 of \S537 becomes two lines (10/29/20)

\tenpoint\noindent
command is being processed.
Beware: For historic reasons, this code foolishly conserves a tiny bit
of string pool space; but that can confuse the interactive `\.E' option.

\bugonpage B214, bottom line (10/29/20)

\ninepoint\noindent
{\bf if} $\\{name}=\\{str\_ptr}-1$ {\bf then}
\ $\{\,$conserve string pool space (but see note above)$\,\}$

\bugonpage B219, lines 18--20 of \S545 (09/19/19)

\tenpoint\noindent
so-called boundary character of this font;
the value of \\{next\_char} need not lie between \\{bc} and~\\{ec}.
If the very last instruction of the \\{lig\_kern} array has $\\{skip%
\_byte}=255$,
there is a special ligature/kerning program for a boundary character at the
left, beginning at location $256\ast\\{op\_byte}+$\cutpar

\bugonpage B282, line 1 {(and change lines 20--23 accordingly)} (04/02/17)

\tenpoint\noindent
{\bf 682.} Each portion of a formula is classified as Ord, Op, Bin, Rel, Open,
Close, Punct, or Inner, for\cutpar

\bugonpage B299, line 4 from the bottom of \S722 (10/06/20)

\ninepoint\noindent\qquad\quad
{\bf begin} \\{char\_warning}(\\{cur\_f}, \\{qo}(\\{cur\_c}));
$\\{math\_type}(a)\gets\\{empty}$;
$\\{cur\_i}\gets\\{null\_character}$;

\bugonpage B318, lines 16 and 17 of \S761 become one (03/25/19)

\ninepoint\noindent
\\{fraction\_noad}: $s\gets\\{fraction\_noad\_size}$;

\bugonpage B333, line 5 of \S793 becomes two lines (01/10/20)

\ninepoint\noindent\quad
$\\{cur\_loop}\gets\\{link}(\\{cur\_loop})$;
$\\{link}(p)\gets\\{new\_glue}(\\{glue\_ptr}(\\{cur\_loop}))$;\par
\noindent\quad
$\\{subtype}(\\{link}(p))\gets\\{tab\_skip\_code}+1$;

\bugonpage B348, insert a new line after line 5 of \S826 (01/15/17)

\ninepoint\noindent\qquad
{\bf stat if} $\\{tracing\_paragraphs}>0$ {\bf then}
\\{end\_diagnostic}(\\{true}); \ {\bf tats}

\bugonpage B348, insert a new line to be the seventh line after the previous change (01/15/17)

\ninepoint\noindent\qquad
{\bf stat if} $\\{tracing\_paragraphs}>0$ {\bf then}
\\{begin\_diagnostic}; \ {\bf tats}

\bugonpage B377, line 6 (10/31/20)

\ninepoint\noindent
\\{hn}: $0\dts64$; \ $\{\,$the number of positions occupied in \\{hc};
                       not always a \\{small\_number}$\,\}$

\bugonpage B417, mini-index (04/02/17)

\eightpoint\noindent
The entry `\\{height}, \S981.' here and on many later
odd-numbered pages should be `$\\{height}=\rm macro$, \S135.'

\bugonpage B522, line 3 of \S1306. (10/25/20)

\tenpoint\noindent
to be in the range $a\le x\le b$.
System error messages should be suppressed when undumping.

\bugonpage B533, lines 5--8 of \S1333. (10/15/20)

\tenpoint\noindent
loop.
(Actually there's one way to get error messages, via \\{prepare\_mag};
but that can't cause infinite recursion.)\par
\noindent\quad
If \\{final\_cleanup} is bypassed, this program doesn't bother to
close the input files that may still be open.

\bugonpage B533, line 12 of \S1333. (11/29/20)

\ninepoint\noindent\quad
{\bf begin} $\langle\,$Finish the extensions{\sevenrm\kern.5em1378}$\,\rangle$;
$\\{new\_line\_char}\gets-1$;

\bugonpage B534, line 6 of \S1335. (11/29/20)

\ninepoint\noindent\quad
{\bf begin} $c\gets\\{cur\_chr}$;
{\bf if} $c\ne1$ {\bf then} $\\{new\_line\_char}\gets-1$;

\bugonpage B537, line 18 of \S1338 becomes two lines (10/05/20)

\ninepoint\noindent\quad
{\bf begin} \\{clear\_terminal};\par
\noindent\quad
{\bf loop}

\bugonpage B537, lines 11 and 12 from the bottom of \S1338
  become three lines (04/02/17)

\ninepoint\noindent\qquad\qquad
{\bf begin goto} \\{breakpoint};\par
\noindent\qquad\qquad\quad$\{\,$go to every declared label at least once$\,\}$\par
\noindent\qquad\quad\\{breakpoint}: $m\gets0$;
 \.{@\char`\{\char`\'BREAKPOINT\char`\'@\char`\}}

\bugonpage B600, the bottom five lines (05/14/19)

\tenpoint\noindent
they occupy in a typical production system
(executable code size for dark blocks, global data size for light blocks).
In this way the chart indicates a total of about
$12\times22=264${\ninerm K} bytes of memory, plus
$12\times10=120${\ninerm K} for the
dynamic memory region not shown explicitly. The dynamic memory
is often considerably larger in practice, because it is desirable to
accommodate large macro packages and large pages.


% volume C
\hsize=29pc
\def\\#1{\hbox{\it#1\/\kern.05em}} % italic type for identifiers
\def\dashto{\mathrel{\hbox{-\thinspace-\kern-.05em}}}
\def\ddashto{\mathrel{\hbox{-\thinspace-\thinspace-\kern-.05em}}}
\def\tension{\mathop{\rm tension}}
\def\controls{\mathop{\rm controls}}
\def\and{\,{\rm and}\,}

\bugonpage Cx, line 4 from the bottom (06/14/20)

\count255=1
\def\diamondleaders{\global\advance\count255 by 1
  \ifodd\count255 \kern-10pt \fi
  \leaders\hbox to 20pt{\ifodd\count255 \kern13pt \else\kern3pt \fi
    .\hss}}
\line{\strut
    \hbox to\parindent{\bf\hbox to 1em{\hss20}\hss}%
    \rm More About Macros\diamondleaders\hfil\hbox to 2em{\hss175}}

\bugonpage C39, lines 10 and 11 become three lines (07/04/20)

\tenpoint\noindent
that has already been designed. All you'll see is
`|(io.mf| |The| |letter| |O| |[79])|' or possibly only `|(io.mf| |[79])|',
followed by~`|*|'. Now the fun starts: You should type

\bugonpage C68, lines 9, 28, 35, 36, 38 (11/11/17)

\ninepoint
\halign{\indent\hbox to 160pt{\tt#\hfil}&\tt#\hfil\cr
uniformdeviate -100&-36.1628\cr
z slanted 1/6&(0.16667y+x,y)\cr
(a,b)zscaled(3,4)&(-4b+3a,3b+4a)\cr
(a,b)zscaled dir 30&(-0.5b+0.86603a,0.86603b+0.5a)\cr
(a,b)dotprod(3,4)&4b+3a\cr
}

\bugonpage C72, lines 4--18 (07/16/20)

\ninepoint\noindent
\beginsyntax
<numeric atom>\is<numeric variable>
 \alt<numeric token primary>
 \alt[(]<numeric expression>[)]
 \alt[normaldeviate]
 \alt[length]<string primary>
 \alt[length]<path primary>
 \alt[length]<pair primary>
 \alt[angle]<pair primary>
 \alt[xpart]<pair primary>
 \alt[ypart]<pair primary>
 \alt<numeric operator><numeric primary>
<numeric token primary>\is<numeric token>[/]<numeric token>
 \alt<numeric token not followed by %
  `{\tt/}$\thinspace\langle$numeric token$\rangle$'\thinspace>
<numeric primary>\is<numeric atom not followed by {[\char'133]<expression>[,]}>
 \alt<numeric atom>[\char'133]<numeric expression>%
   [,]<numeric expression>[\char'135]
\endsyntax

\bugonpage C76, lines  8--16 from the bottom (11/11/17)

\newdimen\longesteq
\setbox0=\hbox{\indent$z_{12}-z_{11}=z_{14}-z_{13}$\quad}
\longesteq=\wd0
\tenpoint\noindent \hangindent\longesteq \hangafter0
tom edge of the type.
\ (With plain \MF's {\bf beginchar} each
character has a ``bounding box'' that runs from $(0,h)$
at the upper left and $(w,h)$ at the upper right to $(0,-d)$ and~$(w,-d)$
at the lower left and lower right; variable $d$ represents the depth of
the type. The values of $w$, $h$, and~$d$ might change from character to
character, since the individual pieces of type need not have the same size
in a computer-produced font.)

\bugonpage C80, line 14 (06/13/20)

\tenpoint\indent
\\{penpos}\<suffix>(\<unknown>,\thinspace\<known>).

\bugonpage C83, line 16 (06/13/20)

\ninepoint\indent
|### 0.5a=-c-0.5b+1.5|

\bugonpage C83, line 19 (06/13/20)

\ninepoint\noindent
the only
dependent variable is now $d$, which equals $0.5c+0.75b+0.75$. \ (This is\cutpar

\bugonpage C96, line 13 from the bottom (10/31/20)

\tenpoint\noindent
illustrates the
use of $u\0$, $s\0$, $\\{ht}\0$, \\{logo\_pen}, \\{leftstemloc}, $o$,
\\{xgap}, and \\{barheight}:

\bugonpage C106, lines 19--21 (07/03/20)

\ninepoint\noindent
pixels. \ (Some typesetting
systems use both of these device-dependent amounts to alter their current
position on a page, just after typesetting each character. Other systems,
like typical |dvi| software associated with \TeX, assume that $\\{chardy}=0$
but use \\{chardx}\cutpar

\bugonpage C113, lines 5--11 from the bottom (07/20/20)

\def\cycle{\hbox{\rm cycle}}
\ninepoint\noindent
\begindisplay
$s\0:=5\\{pt}\0$; \ {\bf define\_pixels}$(s)$; \ \%  side of the square\cr
$z_1=(0,0)$; \ $z_2=(s,0)$; \ $z_3=(0,s)$; \ $z_4=(s,s)$;\cr
{\bf for} $k=1$ {\bf upto} 4:
 $z[k+4]=z[k]+({2\over3}s,{1\over3}s)$; \ {\bf endfor}\cr
{\bf pickup pencircle} scaled $.4\\{pt}$; \
{\bf draw} $z_5\dashto z_6\dashto z_8\dashto z_7\dashto \cycle$;\cr
{\bf pickup pencircle} scaled $1.6\\{pt}$; \
{\bf erase draw} $z_2\dashto z_4\dashto z_3$;\cr
{\bf pickup pencircle} scaled $.4\\{pt}$; \
{\bf draw} $z_1\dashto z_2\dashto z_4\dashto z_3\dashto \cycle$;\cr
{\bf for} $k=1$ {\bf upto} 4:
 {\bf draw} $z[k]\dashto z[k+4]$; \ {\bf endfor}.\cr
\enddisplay

\bugonpage C114, line 7 (07/20/20)

\ninepoint\indent
{\bf for} $k=0$ {\bf upto} 4: \ $z[k]=\\{center}+(\\{radius},0)$
  rotated$(90+{360\over5}k)$; \ {\bf endfor}

\bugonpage C128, lines 13 and 14 (06/13/20)

\ninepoint\noindent
changed. Plain \MF\ has a {\bf tensepath} operation
that does this. For example, {\bf tensepath}~\\{unitsquare}~$=$
$(0,0)\ddashto(1,0)\ddashto(1,1)\ddashto(0,1)\ddashto\cycle$.

\bugonpage C136, lines 18 and 19 (07/17/20)

\ninepoint\noindent
only
about 0.28 with respect to the initial and final directions; since \MF\ insists
that tensions be at least~0.75, this anomalous path could never have arisen
if the control\cutpar

\bugonpage C155, line 7 (10/07/20)

\tenpoint\indent
\<program>\is\<statement list>\<statement>\thinspace|end|

\bugonpage C160, lines 7--9 (06/25/20)

\ninepoint\noindent
might produce a transcript
that includes the following diagnostic information:
\begintt
rotatedaround(EXPR0)(EXPR1)->
 shifted-(EXPR0)rotated(EXPR1)shifted(EXPR0)
\endtt

\bugonpage C165, lines 5--7 from the bottom (11/11/17)

\ninepoint\noindent
(i.e., parameters in parentheses),
then we name zero or one or two undelimited parameters.
Then comes an `$=$'~sign,
followed by the replacement text, and {\bf enddef}. The `$=$'~sign might also
be~`$:=$'\thinspace; both mean the same thing.

\bugonpage C171, lines 18--20 (08/16/20)

\ninepoint\indent
Chapter~14's syntax rules for
\<path primary>, via \<pair primary>.
A pair expression is not considered to be
of type {\bf path} unless the path interpretation is the only~possibility.

\bugonpage C176, line 7 from the bottom (07/09/20)

\ninepoint\indent
\quad {\bf if} |@#|$(\\{x\_})\colon\ \\{tx\_} \ \hbox{\bf else}\colon\
 \\{fx\_}\  \hbox{\bf fi}$
   :=\ \\{x\_}\thinspace; {\bf endfor}

\bugonpage C180, line 3 from the bottom (06/24/20)

\ninepoint\indent
`$=$' or `$:=$' following {\bf let}.

\bugonpage C187, line11 from the bottom (07/12/20)

\ninepoint\indent\qquad
\alt|substring|\thinspace\<pair expression>\thinspace|of|\thinspace
 \<string primary>

\bugonpage C189, line 14 (06/13/20)

\ninepoint\noindent
`|! |' and followed
by~`|.|', followed by lines of context as in \MF's normal error\cutpar

\bugonpage C200, line 12 from the bottom (08/27/20)

\ninepoint\indent
$y_1=y_2=\\{good.y}(.5[-d,h]+1.1\\{pt})$;

\bugonpage C202, line 17 from the bottom (06/13/20)

\ninepoint\noindent
command,
and it works only when the \\{penpos} angle is~0. If the \\{penpos} command
is\cutpar

\bugonpage C210, bottom eight lines, and top ten lines of page C211 (07/16/20)

\ninepoint\noindent
\beginsyntax
<numeric atom>\is<numeric variable>\alt<numeric argument>
 \alt<numeric token primary>
 \alt<internal quantity>
 \alt[normaldeviate]
 \alt[(]<numeric expression>[)]
 \alt[begingroup]<statement list><numeric expression>[endgroup]
 \alt[length]<numeric primary>\alt[length]<pair primary>
 \alt[length]<path primary>\alt[length]<string primary>
 \alt[ASCII]<string primary>\alt[oct]<string primary>\alt[hex]<string primary>
 \alt<pair part><pair primary>\alt<transform part><transform primary>
 \alt[angle]<pair primary>
 \alt[turningnumber]<path primary>\alt[totalweight]<picture primary>
 \alt<numeric operator><numeric primary>
 \alt[directiontime]<pair expression>[of]<path primary>
<numeric token primary>\is<numeric token>[/]<numeric token>
 \alt<numeric token not followed by %
  `{\tt/}$\thinspace\langle$numeric token$\rangle$'\thinspace>
<numeric primary>\is<numeric atom not followed by {[\char'133]<expression>[,]}>
 \alt<numeric atom>[\char'133]<numeric expression>%
   [,]<numeric expression>[\char'135]
\endsyntax

\bugonpage C214, line 6 becomes two lines (07/17/20)

\ninepoint\noindent
\beginsyntax
<future pen primary>\is<future pen argument>
 \alt[pencircle]
\endsyntax

\bugonpage C214, line 6 from the bottom (07/12/20)

\ninepoint\noindent
\beginsyntax
 \alt[substring]<pair expression>[of]<string primary>
\endsyntax

\bugonpage C217, lines 20--25 (10/07/20)

\ninepoint\noindent
\beginsyntax
<program>\is<statement list><non-title statement>[end]
 \alt<statement list><non-title statement>[dump]
<statement list>\is<empty>\alt<statement>[;]<statement list>
<statement>\is<empty>\alt<title>
 \alt<equation>\alt<assignment>\alt<declaration>
 \alt<definition>\alt<compound>\alt<command>
\endsyntax

\bugonpage C219, line 25 (05/25/20)

\ninepoint\noindent
to see which of its subscripts and suffixes have occurred.
For example, if you're\cutpar

\bugonpage C224, lines 7--9 from the bottom (12/21/18)

\tenpoint\indent
|y4r=-0.9848thinn+259.00049|\par
|x4r=-0.08682thinn+144|\par
|y4=-0.4924thinn+259.00049|

\bugonpage C226, lines 9 and 10 (11/01/20)

\ninepoint\noindent
This means that the preloaded base you have specified cannot be used,
because it is corrupted or was prepared for a different version of
\MF\kern-.03em.

\bugonpage C228, line 27 (06/19/20)

\ninepoint\indent
|l.94 endfor|

\bugonpage C228, line 4 from the bottom (07/12/20)

\ninepoint\noindent
might want to review now.) \
You probably also have a |proof| mode diagram:

\bugonpage C234, line 4 of answer 4.6 (07/20/20)

\ninepoint\indent
{\bf for} $k=1$ {\bf upto} 6: $z[k]'=.2[z[k],z_0]$; {\bf endfor}

\bugonpage C241, line 2 (11/11/17)

\ninepoint\indent
|\mode=cheapo; input cheaplogo10|

\bugonpage C242, line 11 of answer 13.7 (07/20/20)

\ninepoint\indent
{\bf for} $k=1$ {\bf upto} 4:
 $z[k+4]=z[k]+({2\over3}s,{1\over3}s)$; \ {\bf endfor}

\bugonpage C243, lines 7 and 8 (11/08/15)

\ninepoint\indent
\indent {\bf draw} subpath$(k,k+1)$ of \\{star}; {\bf cullit};\par\indent
\indent {\bf undraw} subpath$(k+2,k+3)$ of \\{star} {\bf withpen}
  \\{eraser}; {\bf cullit};

\bugonpage C243, line 3 of answer 13.11 (06/17/20)

\ninepoint\indent
{\bf def overdraw expr} $c$ = {\bf begingroup save} \\{region};

\bugonpage C243, lines 12--16 of answer 13.11 (05/24/20)

\ninepoint\noindent
\begindisplay
{\bf beginchar}$(\hbox{\tt"M"},1.25\\{in}\0,.5\\{in}\0,0)$; \
 {\bf pickup pencircle} scaled .4\\{pt};\cr
$z_1=(20,-13)$; \ $z_2=(30,-6)$; \ $z_3=(20,1)$; \ $z_4=(4,-7)$;\cr
\indent $z_5=(-12,-13)$; \ $z_6=(-24,-4)$; \ $z_7=(-15,6)$;\cr
{\bf path} $M$; $M=(\\{origin}\dts
 z_1\dts z_2\dts z_3\dts z_4\dts z_5\dts z_6\dts z_7\dts$\cr
\indent$\\{origin}\dts -z_7\dts -z_6\dts -z_5\dts -z_4\dts
  -z_3\dts -z_2\dts -z_1\dts\cycle)$\cr
\enddisplay

\bugonpage C246, line 2 of answer 14.13 (08/16/20)

\ninepoint\noindent
path $z_0\dashto z_1$ is equivalent to `$z_0\dts
\controls1/3[z_0,z_1]\and2/3[z_0,z_1]\dts z_1$', and the\cutpar

\bugonpage C247, line 1 of answer 15.5 (06/13/20)

\ninepoint\noindent
\quad{\bf 15.5.}\enspace
{\bf beginchar}$(126,25u\0,\\{h\_height}\0+\\{border}\0,0)$; \
|"Dangerous left bend"|;

\bugonpage C247, replacement for answer 15.7 (07/21/20)

\ninepoint\noindent
\quad{\bf 15.7.}\enspace
Replace lines 10 and 11 by
\begindisplay
{\bf pickup pencircle} scaled 3/4\\{pt} yscaled 1/3 rotated $-60$;\cr
{\bf draw} ($z_1\ldots p$) transformed $t$;\cr
{\bf addto} \\{currentpicture} {\bf also} \\{currentpicture}\cr
\qquad rotatedaround$\bigl((.5w,.5h)$ yscaled \\{aspect\_ratio}$,-180\bigr)$;\cr
\enddisplay

\bugonpage C249, line 1 of answer 18.9 (08/02/20)

\ninepoint\noindent
\quad{\bf 18.9.}\enspace
{\bf beginchar}\kern1pt(|"H"|$,13u\0,"ht"\0,0)$; \
 {\bf pickup} \\{broad\_pen};

\bugonpage C249, line 11 of answer 18.9 (08/02/20)

\ninepoint\indent
{\bf filldraw} $\\{bot\_serif\_edge}_4$

\bugonpage C250, line 4 of answer 19.1 (04/19/20)

\ninepoint\noindent
because it saves a wee bit of time and because
`;'\ often belongs before {\bf endfor}.

\bugonpage C250, replacement for answer 19.3 (07/12/20)

\ninepoint\noindent
\quad{\bf 19.3.}\enspace
Yes, if and only if $n-{1\over2}$ is an even integer.
\ (Because ambiguous values are rounded upwards.)

\bugonpage C251, replacement for answer 22.1 (07/12/20)

\ninepoint\noindent
\quad{\bf 22.1}\enspace
(a) If and only if $n$ is an integer between 0 and 255.
(b) If and only if $s$ is a string of length~1.

\bugonpage C254, lines 10--13 from the bottom become five lines (06/26/20)

\ninepoint\noindent
\begintt
? H
I found no right delimiter to match a left one. So I've
put one in, behind the scenes; this may fix the problem.
|null
?
\endtt

\bugonpage C260, the ``line'' after line 3 (06/14/20)

\def\bb{$\,\left\{\vcenter\bgroup\halign\bgroup\hfil##\hfil\cr}
\def\ee{\crcr\egroup\egroup\right\}\,$}
\tenpoint\noindent
\bb|font_size|\cr|font_slant|\cr|font_normal_space|\cr
 |font_normal_stretch|\cr|font_normal_shrink|\cr|font_x_height|\cr
 |font_quad|\cr|font_extra_space|\ee
\bb|=|\cr\noalign{\kern-2pt}|:=|\cr\noalign{\kern-2pt}\<empty>\ee
\<numeric$\0$>; \
\bb|ligtable|\<ligs/kerns>\cr|charlist|\<codes>\cr|extensible|\<codes>\cr
 |fontdimen|\<info>\cr|headerbyte|\<info>\ee;\kern-10pt

\bugonpage C261, lines 16 and 17 from the bottom (06/14/20)

\tenpoint\noindent
\bb|proofrule|\cr|screenrule|\ee|(|\<pair>|,|\<pair>|)|; \
|makegrid(|\<numerics>|)(|\<numerics>|)|;\smallskip\noindent
|proofrulethickness| \<numeric$\0$>; \ |proofoffset| \<pair>.

\bugonpage C266, lines 19 and 20 (07/04/20)

\ninepoint\noindent
You can say either `|incr|~|x|' or `|incr|~|(x)|', within
an expression; but neither of them are valid statements by themselves.

\bugonpage C269, line 11 (01/10/21)

\ninepoint\indent
|\smode="specmode"; mag=|\<magnification>|; input |\<font file name>

\bugonpage C277, lines 15--19 (03/06/17)

\ninepoint\noindent
|def openit = openwindow currentwindow from origen    % and please correct|\par
\noindent
| to (screen_rows,screen_cols) at (-50,300) enddef;   % "(-50,300)" too|\par
\noindent
|def showit_ = display currentpicture inwindow currentwindow enddef;|\par
\noindent
|def showit = openit; let showit=showit_; showit enddef; % first time only|\par
\kern3pt\hrule\medskip\noindent
Plain \MF\ has several other terse commands
similar to `{\bf openit}' and `{\bf showit}':

\bugonpage C279, line 1 (11/11/17)

\ninepoint\noindent
| blacker:=.1;                   % make pens a teeny bit blacker|

\bugonpage C289, line 20 (10/07/20)

\ninepoint\indent
|if {{(pair x) cand x>(0,0)}}: A else: B fi.|

\bugonpage C291, line 18 (07/24/20)

\ninepoint\indent
| save u_; setu_ u; let switch_ = if; if false: enddef.|

\bugonpage C292, line 10 from the bottom (10/23/20)

\ninepoint\noindent
be known by saying `{\bf if} known $(p-q)$: $p=q$ {\bf else}:~{\bf false fi}';
transforms could be handled\cutpar

\bugonpage C293, lines 13 and 14 from the bottom (10/27/20)

\ninepoint\noindent
$f(-1)$ is false! When $c\rightarrow0$, the quantity $a^3+b^3$
approaches $-\infty$ when $c$~is positive, $+\infty$ when $c$~is
negative. An attempt to `\\{solve} $f(1,-1)$' will divide by zero and
come\cutpar

\bugonpage C295, line 2 (07/04/20)

\ninepoint\noindent
`interpolate $(1,1)\dts(3,2)\dts(15,4)$ of~7' the approximate value 3.37.

\bugonpage C299, bottom four lines of code become five (08/06/20)

\ninepoint\noindent
\begintt
primarydef t Bernshtein nn = begingroup save r; r =
 begingroup for n=nn downto 2:
  for k=1 upto n-1: u_[[[k]]]:=t[[[u_[[[k]]],u_[[[k+1]]] ]]];
  endfor endfor u_[[[1]]] endgroup; numeric u_[[[]]];
 r endgroup enddef;
\endtt

\bugonpage C299, line 5 after the code becomes two lines (08/06/20)

\ninepoint\noindent
brackets are nested inside of brackets.
However, the auxiliary variables `|u_[[[|$k$|]]]|' must not remain
independent at the end.

\bugonpage C305, lines 14--18 (07/08/20)

\ninepoint\noindent
|width_adj#:=0pt#;         % width adjustment for certain characters|\par
\noindent
|serif_fit#:=0pt#;         % extra sidebar near lowercase serifs|
\vskip-3pt\noindent\qquad\vdots\par\noindent
|low_asterisk:=false;      % should the asterisk be centered at the axis?|\par
\noindent
|math_fitting:=false;      % should math-mode spacing be used?|

\bugonpage C317, line 21 becomes two lines (11/11/17)

\ninepoint\noindent
\beginsyntax
<label>\is<code label>\alt<code>[::]\alt[\\\\:]
<code label>\is\<code>[:]
\endsyntax

\bugonpage C318, lines 10--16 from the bottom (11/11/17)

\ninepoint\noindent
\beginsyntax
 \alt<code label><labeled code>
<extensible command>\is[extensible]<code label><four codes>
<four codes>\is<code>[,]<code>[,]<code>[,]<code>
\endsyntax
Notice that a \<code label> can appear in a {\bf ligtable}, {\bf charlist}, or
{\bf extensible} command.
 These appearances are mutually exclusive: No code may be
used more than once as a label. Thus, for example, a character with a
ligature/kerning program cannot also be {\bf extensible}, nor can it be
in a {\bf charlist} (except as the final item).

\bugonpage C333, line 29 (10/25/19)

\ninepoint\noindent
|  "if charcode>0:currentpicture:=currentpicture scaled mg;fi;"|

\bugonpage C333, bottom two lines become one (11/11/17)

\ninepoint\noindent
| if unknown scale: scale := max(1,round(pixels_per_inch/300)); fi|

\bugonpage C339, line 3 (05/21/20)

\ninepoint\noindent
ing `\char'31', `\char'32',
`\char'33', and~`\char'34') and the uppercase letters (including
`\char'35', `\char'36', and~`\char'37') are\cutpar

\bugonpage C341, line 14 from the bottom (11/11/17)

\ninepoint\noindent
prints the |\table| and the |\text|; ^|\bigtest| gives
you the works, plus a mysterious word\cutpar

\bugonpage C345 and following, selected amendments to the index (01/20/21)

\eightpoint
*|,| (comma), 57, 72, 73, 129, 155, 165--167, 171, 211--213, 218, 317, 318.\par
`A', 10--11, 163, 164, 248, 302--303.\par
\<addto command>, 118, $\underline{220}$.\par
bell-shaped distribution, $\underline{183}$, 251.\par
|black|, 270, 332--333.\par
\<code> and \<code label>, $\underline{317}$.\par
concatenation, of paths, {\it70}--{\it71}, {\it123}, 127--129, $\underline{130}$, 137, {\it245}, {\it266}.\par
\quad of strings, {\it69}, 73, 84--85, $\underline{187}$, {\it278}, {\it286}, {\it312}.\par
*|directiontime|, {\it135}, $\underline{\it136}$, 211, 245, 265, {\it298}.\par
distance, 76, 84, {\sl see also\/} |length|.\par
|dotprod|, {\it68}--{\it69}, 178, {\it238}, 265.\par
efficiency, 39, 99, 116, 141, 144, 147, 228, 230, 234, 244, 264, 265, 277,  291, 297, 298.\par
empty option in {\bf for\/} list, 171, $\underline{172}$, {\it299}.\par
forbidden tokens, 173, $\underline{218}$--$\underline{219}$, 286.\par
*|from|, $\underline{191}$, 220, {\it252}, {\it277}, {\it312}.\par
Giotto di Bondone, 139.\par
independent variables, $\underline{81}$--$\underline{83}$, 88, 224, 226, 299.\par
|\init|, $\underline{337}$, 342.\par
internal quantities, 54--55, 88, 218, 262, 265--266.\par
*|inwindow|, $\underline{191}$, 220, {\it277}.\par
\<keep or drop>, $\underline{118}$, 220.\par
|labels|, {\it107}, $\underline{274}$, 327--328.\par
*|length|, {\it66}, {\it69}, 72, 210, 238.\par
*|ligtable|, {\it97}, {\it305}--{\it306}, $\underline{316}$--$\underline{317}$.\par
loops, 169, 171--173, 179, 226--227, 259, 290--291, 299.\par
`N', 184--185, 302--303.\par
\<numeric token primary>, 72, $\underline{211}$.\par
|o|, {\it23}, {\it34}, $\underline{93}$, 197, 200, 204, 240, 302.\par
`O', 32--37, 161, 199, 302--303.\par
overshoot, 23, 34, 93, 197, 200, 204, 302.\par
|penpos|, {\it26}--{\it29}, 37, 80, {\it103}, {\it162}, $\underline{273}$, 310.\par
pens, 21--29, 147--152, 297--298.\par
*|rotated|, {\it21}--{\it22}, {\it25}, 27, 44, {\it68}, 73, {\it107}, {\it114}, {\it117}, $\underline{141}$, 213, {\it238}.\par
|rule|, 274, 328.\par
*|scaled|, {\it21}--{\it23}, {\it68}, 73, $\underline{141}$, 213, 244, 291.\par
*|showstopping|, 211, 219, {\it227}, 230, {\it262}.\par
string expressions, {\it69}, 187--189, 258, 286.\par
\<suffix list>, $\underline{171}$, 236.\par
sum, of vectors, 9, {\it68}.\par
|test.mf|, 311--313.\par
\TeX, 1, 34, 40, 91, 96, 98, 101--103, 315, 336--343, 361.\par
text arguments, 219, 288--291, 299.\par
|.tfm|, 39, 315--321, 333, 335.\par
*|to|, $\underline{191}$, 220, {\it252}, {\it277}, {\it312}.\par
undelimited suffix parameters, $\underline{167}$, 176, 266, 270.\par
|undraw|, 113, 118, 120, {\it242}, $\underline{271}$.\par
|unitsquare|, {\it116}, 123--124, 128, 132, 136, $\underline{263}$.\par
*|unknown|, $\underline{170}$, 210.\par
unknown quantities, nonnumeric, 84--85, 143.\par
values, disappearance of, 56, 83, 88, 156--157, 177--178, 218, 239, 299.\par
\<vardef heading>, 165, $\underline{178}$.\par
*|xscaled|, {\it21}--{\it22}, {\it68}, 73, $\underline{141}$, 213, 244, 291.\par



% Volume D
\def\\#1{\hbox{\it#1\/\kern.05em}} % italic type for identifiers
\def\to{\mathrel{.\,.}} % double dot, used only in math mode

\bugonpage Dv, line 16 (01/16/21)

\tenpoint\noindent
\kern12.5mm I believe that the final bug in \MF\ was discovered on January\cutpar

\bugonpage Dv, bottom two lines (01/16/21)

\eightpoint\noindent
corporates all of those changes.
I~now believe that the final bug was discovered on 03 July 2020
and removed in version 2.71828182. % on 16 January 2021
The finder's fee has converged to \$327.68.

\hsize=35pc

\bugonpage D2, last line of \S2 (01/15/21)

\ninepoint\noindent
$$\hbox{{\bf define} $\\{banner}\equiv\.{\char`\'This\]is\]METAFONT,\]Version\]2.71828182\char`\'}$\quad
$\{\,$printed when \MF\ starts$\,\}$}$$

\bugonpage D14, line 1 of \S30 (05/05/14)

\tenpoint\noindent
{\bf 30.} \quad The \\{input\_ln} function brings the next line of input from the specified
file into available\cutpar

\bugonpage D21, line 8 of \S47 (10/11/20)

\ninepoint\noindent\quad
$g$: \\{str\_number};\quad$\{\,$the string just created$\,\}$

\bugonpage D27, lines 3 and 4 of \S61 (04/02/17)

\tenpoint\noindent
is not serious since we assume that this
part of the program is system dependent.

\bugonpage D28, line 7 (04/02/17)

\ninepoint\noindent\quad
{\bf var} $k$: $0\dts23$;\quad$\{\,$index to current digit; we assume
 that $\vert n\vert<10^{23}\,\}$

\bugonpage D32, line 2 of \S78 becomes two lines (06/27/20)

\ninepoint\noindent\quad
{\bf loop begin} \\{continue}: {\bf if} $\\{interaction}\ne\\{error\_stop\_mode}$
  {\bf then return};\par
\noindent\qquad
\\{clear\_for\_error\_prompt}; \ \\{prompt\_input}(\.{"?\]"});

\bugonpage D32, line 11 of \S79 (07/03/20)

\ninepoint\noindent\quad
\.{"E"}: {\bf if} $\\{file\_ptr}>0$ {\bf then if}
 $\\{input\_stack}[\\{file\_ptr}].\\{name\_field}\ge256$ {\bf then}

\bugonpage D33, line 5 of \S80 (07/03/20)

\ninepoint\noindent\quad
{\bf if} $\\{file\_ptr}>0$ {\bf then}\par
\noindent\qquad
{\bf if} $\\{input\_stack}[\\{file\_ptr}].\\{name\_field}\ge256$ {\bf then}
\\{print}(\.{"E\]to\]edit\]your\]file."}

\bugonpage D37, line 9 of \S93 (08/07/20)

\ninepoint\noindent\qquad
(\.{"Try\]to\]insert\]an\]instruction\]for\]me\](e.g.,\]%
        \char`\`I\]show\]x;\char`\'),"})

\bugonpage D82, line 2 from the bottom (09/19/19)

\ninepoint\noindent\quad
{\bf define} $\\{boundary\_char}=41$\quad$\{\,$the boundary character for ligatures$\,\}$

\bugonpage D85, lines 3 and 4 of \S194 {(and \S194 actually moves to page D86)} (12/11/20)

\tenpoint\noindent
information, something special
is needed. The program here simply assumes that suitable values appear in
the global variables \\{sys\_time}, \\{sys\_day}, \\{sys\_month}, and
\\{sys\_year} (which are initialized to noon on 4 July 1776,
in case the implementor is careless).

\bugonpage D85, the final six lines of \S194 {(and \S194 actually moves to page D86)} (12/11/20)

\ninepoint\noindent
{\bf procedure} \\{fix\_date\_and\_time};\par
\noindent\quad{\bf begin}
$\\{sys\_time}\gets12\ast60$; \
$\\{sys\_day}\gets4$; \
$\\{sys\_month}\gets7$; \
$\\{sys\_year}\gets1776$;\quad
$\{\,$self-evident truths$\,\}$\par
\noindent\quad$\\{internal}[\\{time}]\gets\\{sys\_time}\ast\\{unity}$;\quad
  $\{\,$minutes since midnight$\,\}$\par
\noindent\quad$\\{internal}[\\{day}]\gets\\{sys\_day}\ast\\{unity}$;\quad$\{\,$day of the month$\,\}$\par
\noindent\quad$\\{internal}[\\{month}]\gets\\{sys\_month}\ast\\{unity}$;\quad$\{\,$month of the year$\,\}$\par
\noindent\quad$\\{internal}[\\{year}]\gets\\{sys\_year}\ast\\{unity}$;\quad$\{\,$Anno Domini$\,\}$\par
\noindent\quad{\bf end};

\bugonpage D86, replacement for \S196 (12/11/20)

\tenpoint\noindent
{\bf 196.}\quad Of course we had better declare a few more global variables,
if the previous routines are going to work.
\smallskip
\ninepoint\noindent
$\langle\,$Global variables {\sevenrm\kern.5em13}$\,\rangle+\equiv$\par
\noindent\\{old\_setting}: $0\dts\\{max\_selector}$;\par
\noindent\\{sys\_time}, \\{sys\_day}, \\{sys\_month}, \\{sys\_year}: \\{integer};
\quad$\{\,$date and time supplied by external system$\,\}$

\bugonpage D97, line 2 of \S221 (05/26/17)

\tenpoint\noindent
the definition of attribute nodes) that
it is convenient to let $\\{info}(p)=0$ stand for `\.{[]}'.

\goodbreak
\bugonpage D148, line 7 (06/12/18)

\tenpoint\noindent
but the $\log n$ factor is buried in our
implicit restriction on the maximum raster size.) The\cutpar

\bugonpage D237, line 5 of \S513 (05/26/17)

\ninepoint\noindent\quad
{\bf for} $n\gets0$ {\bf to} $\\{n1}-\\{n0}-1$ {\bf do} $\\{env\_move}[n]\gets\\{mm0}$;

\bugonpage D250, line 2 of \S534 (05/26/17)

\tenpoint\noindent
direction $\bigl(\\{right\_u}(p),\\{left\_v}(q)\bigr)$;
and there's a line of length $\ge\\{delta}$ from vertex~$q$ to vertex~$r$,\cutpar

\bugonpage D296, line 11 (06/23/20)

\tenpoint\noindent
\\{name} points to the \\{eqtb} address of the macro
being expanded, if the current token list\cutpar

\bugonpage D324, line 13 of \S713 (12/20/20)

\ninepoint\noindent\qquad\quad
\\{help2}(\.{"After\]\char`\`exitif\]<boolean\]expr>\char`\'\]I\]expect\]to\]see\]a\]%
semicolon."})

\bugonpage D326, line 5 from the bottom (06/23/20)

\ninepoint\noindent\qquad\qquad
$\{\,$invokes a user-defined sequence of commands$\,\}$

\bugonpage D334, lines 1 and 2 of \S742 (10/25/20)

\tenpoint\noindent
{\bf 742.} \ Here is a procedure that ignores text until coming to an {\bf elseif},
{\bf else}, or {\bf fi} at the current level of {\bf if}$\,\ldots\,${\bf fi}
nesting. After it has acted, \\{cur\_mod} will indicate the token that
was found.

\bugonpage D339, line 4 of \S757 (06/16/20)

\tenpoint\noindent\quad
(A user who tries some shenanigan like `{\bf for} $\ldots$ {\bf let} {\bf endfor}'
will be foiled by the \\{get\_symbol}\cutpar

\bugonpage D351, lines 2--7 of \S790 become five lines (12/11/20)

\ninepoint\noindent\quad
{\bf begin} \\{wlog}(\\{banner});
\\{slow\_print}(\\{format\_ident});
\\{print}(\.{"\]\]"});
\\{print\_int}(\\{sys\_day});
\\{print\_char}(\.{"\]"});\par
\noindent\quad
$\\{months}\gets\.{\char`\'JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC\char`\'}$;\par
\noindent\quad
{\bf for} $k\gets3\ast\\{sys\_month}-2$ {\bf to} $3\ast\\{sys\_month}$
{\bf do} \\{wlog}(\\{months}[$k$]);\par
\noindent\quad
\\{print\_char}(\.{"\]"});
\\{print\_int}(\\{sys\_year});
\\{print\_char}(\.{"\]"});
\\{print\_two}(\\{sys\_time} {\bf div} 60);
\\{print\_char}(\.{":"});\par
\noindent\quad
\\{print\_two}(\\{sys\_time} {\bf mod} 60);

\bugonpage D352, line 2 of \S793 becomes two lines (10/29/20)

\tenpoint\noindent
command is being processed.
Beware: For historic reasons, this code foolishly conserves a tiny bit
of string pool space; but that can confuse the interactive `\.E' option.

\bugonpage D352, line 5 from the bottom (10/29/20)

\ninepoint\noindent
{\bf if} $\\{name}=\\{str\_ptr}-1$ {\bf then}
\ $\{\,$conserve string pool space (but see note above)$\,\}$

\bugonpage D354, line 2 from the bottom (07/29/20)

\tenpoint\noindent
$\\{cur\_type}=\\{path\_type}$ means that \\{cur\_exp} points to the first
node of
a path; nobody else points\cutpar

\bugonpage D469, lines 18--20 of \S1093 (09/19/19)

\tenpoint\noindent
so-called boundary character of this font;
the value of \\{next\_char} need not lie between \\{bc} and~\\{ec}.
If the very last instruction of the \\{lig\_kern} array has $\\{skip%
\_byte}=255$,
there is a special ligature/kerning program for a boundary character at the
left, beginning at location $256\ast\\{op\_byte}+$\cutpar

\bugonpage D469, line 30 of \S1093 (01/15/21)

\tenpoint\noindent
tional halt; no ligature or kerning command is performed.

\bugonpage D471, lines 20 and 21 (08/07/20)

\ninepoint\noindent
\\{param}: {\bf array} $[1\dts\\{max\_font\_dimen}]$ {\bf of}
\\{scaled};\quad$\{\,${\bf fontdimen} parameters$\,\}$\par\noindent
\\{np}: $0\dts\\{max\_font\_dimen}$;\quad$\{\,$the largest {\bf fontdimen} parameter
specified so far$\,\}$

\bugonpage D474, line 2 from the bottom (08/07/20)

\ninepoint\noindent\quad\qquad
\\{help1}(\.{"A\]colon\]should\]follow\]a\]headerbyte\]or\]fontdimen\]location."});
\\{back\_error};

\bugonpage D508, line 3 of \S1189. (10/05/20)

\tenpoint\noindent
to be in the range $a\le x\le b$.
System error messages should be suppressed when undumping.

\bugonpage D516, line 6 (10/15/20)

\tenpoint\noindent\quad
If \\{final\_cleanup} is bypassed, this program doesn't bother to
close the input files that may still be open.

\bugonpage D519, line 17 (01/15/21)

\ninepoint\noindent\quad
\\{fix\_date\_and\_time};
$\\{init\_randoms}(\\{sys\_time}+\\{sys\_day}*\\{unity})$;

\bugonpage D520, line 18 of \S1212 becomes two lines (10/05/20)

\ninepoint\noindent\quad
{\bf begin} \\{clear\_terminal};\par
\noindent\quad
{\bf loop}

\bugonpage D520, lines 11 and 12 from the bottom of \S1212
  become three lines (04/02/17)

\ninepoint\noindent\qquad\qquad
{\bf begin goto} \\{breakpoint};\par
\noindent\qquad\qquad\quad$\{\,$go to every declared label at least once$\,\}$\par
\noindent\qquad\quad\\{breakpoint}: $m\gets0$;
 \.{@\char`\{\char`\'BREAKPOINT\char`\'@\char`\}}

\bugonpage D566, the bottom five lines (05/14/19)

\tenpoint\noindent
they occupy in a typical production system
(executable code size for dark blocks, global data size for light blocks).
In this way the chart indicates a total of about
$8\times22=176${\ninerm K} bytes of memory, plus
$8\times15=120${\ninerm K} for the
dynamic memory region not shown explicitly. The dynamic memory
is often considerably larger in practice, because it is desirable to
accommodate large macro packages and large pictures.


% volume E
\hsize=29pc

\newbox\shorthyf \setbox\shorthyf=\hbox{-\kern-.05em}
\mathchardef\period=`\.
{\catcode`\-=\active \global\def-{\copy\shorthyf\mkern3.9mu}
 \catcode`\.=\active \global\def.{\period\mkern3mu}}
\def\8#1{\mathrel{\mathcode`\.="8000 \mathcode`\-="8000
  #1\unkern}} % `..' and `--'


\bye