elwell@osu-eddie.UUCP (Clayton M. Elwell) (09/05/86)
This is part 1/2 of DVIDOC, a DVI to ASCII file converter. See the
enclosed README nad DVIDOC.HLP files for more info.
-------------------------CUT HERE---------------------------
#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
# README
# doc.pl
# docmac.tex
# dvidoc.hlp
# dvidoc.web
# This archive created: Fri Sep 5 12:27:26 1986
export PATH; PATH=/bin:$PATH
if test -f 'README'
then
echo shar: will not over-write existing file "'README'"
else
cat << \SHAR_EOF > 'README'
DVIDOC is a WEB program written a very long time ago at Ohio State University.
It is not an official product.
It is not used very often even here at OSU.
It will not be supported by anyone at OSU, INCLUDING the author.
THIS PROGRAM IS A HACK.
It is based on an ancient Babylonian version of DVITYPE. I don't even
know if the WEB file will go through modern versions of tangle, weave, &
TeX. If not, oh well. Life's tough.
If you do get it working, have a fun time. If not, it could show you
one approach to solving the problem of generating ASCII files from TeX output.
Enjoy...
SHAR_EOF
fi # end of overwriting check
if test -f 'doc.pl'
then
echo shar: will not over-write existing file "'doc.pl'"
else
cat << \SHAR_EOF > 'doc.pl'
(COMMENT OSU DOC file font)
(COMMENT Derived from amtt)
(CODINGSCHEME TEX TYPEWRITER TEXT)
(DESIGNSIZE R 13.76574)
(COMMENT DESIGNSIZE IS IN POINTS)
(COMMENT OTHER SIZES ARE MULTIPLES OF DESIGNSIZE)
(CHECKSUM O 10653670734)
(SEVENBITSAFEFLAG TRUE)
(TEXINFO
(SLANT R 0.0)
(SPACE R 0.5249996)
(STRETCH R 1.049999)
(SHRINK R 0.0)
(XHEIGHT R 0.4305553)
(QUAD R 0.5249996)
(EXTRASPACE R 0.5249996)
)
(LIGTABLE
(LABEL O 47)
(LIG O 47 O 42)
(STOP)
(LABEL O 140)
(LIG O 140 O 42)
(STOP)
)
(CHARACTER O 41
(CHARWD R 0.5249996)
(CHARHT R 0.6111106)
)
(CHARACTER O 42
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(CHARHT R 0.6111106)
)
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)
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(CHARHT R 0.6944446)
(CHARDP R 0.0833330)
)
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)
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)
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(CHARACTER C A
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(CHARACTER C M
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(CHARACTER C N
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(CHARACTER C O
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(CHARACTER C T
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(CHARACTER C U
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(CHARACTER C V
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(CHARACTER C X
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(CHARACTER C Y
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(CHARACTER C g
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)
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)
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(CHARACTER C l
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(CHARACTER C m
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)
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)
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)
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)
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)
(CHARACTER O 175
(CHARWD R 0.5249996)
(CHARHT R 0.6944446)
(CHARDP R 0.0833330)
)
(CHARACTER O 176
(CHARWD R 0.5249996)
(CHARHT R 0.6111106)
)
SHAR_EOF
fi # end of overwriting check
if test -f 'docmac.tex'
then
echo shar: will not over-write existing file "'docmac.tex'"
else
cat << \SHAR_EOF > 'docmac.tex'
\baselineskip=12bp
\font\docfont=doc
\textfont0=\docfont \scriptfont0=\docfont \scriptscriptfont0=\docfont
\def\rm{\fam0\docfont}
\textfont1=\docfont \scriptfont1=\docfont \scriptscriptfont1=\docfont
\def\mit{\fam1} \def\oldstyle{\fam1\docfont}
\def\it{\fam\itfam\docfont} % \it is family 4
\textfont\itfam=\docfont
\def\sl{\fam\slfam\docfont} % \sl is family 5
\textfont\slfam=\docfont
\def\bf{\fam\bffam\docfont} % \bf is family 6
\textfont\bffam=\docfont \scriptfont\bffam=\docfont
\scriptscriptfont\bffam=\docfont
\def\tt{\fam\ttfam\docfont} % \tt is family 7
\textfont\ttfam=\docfont
\footline={\hss\rm\folio\hss}
\def\TeX{TeX}
\rm
SHAR_EOF
fi # end of overwriting check
if test -f 'dvidoc.hlp'
then
echo shar: will not over-write existing file "'dvidoc.hlp'"
else
cat << \SHAR_EOF > 'dvidoc.hlp'
The program DVIDOC will convert a dvi file into a doc file for display
on a terminal or line printer. It will put characters into the doc
file as close as possible to the positions specified by TeX, so
without careful choice of font and spacing, characters will obliterate
others. I hacked together a font called doc that works fairly well in
this mode. To make use of it instead of the plain format's default
roman, italic, slanted, bold, and typewriter fonts, make the first
line in your TeX file `\input docmac'. Don't try math mode with
DVIDOC.
To run DVIDOC simply type, just type the program name as a command.
The program will prompt you for the names of the dvi file and the doc
file. These you should enter with their extensions. It then will ask
you for five parameter values, one at a time. If you like the default
values given in the prompts, you can reply to each question with just
a carriage return. The prompts are for (1) the page number at which
DVIDOC should start translating, (2) the maximum number of pages that
should be translated, (3) the number of characters per inch
horizontally of the ultimate output device, (4) the number of
characters per inch vertically of the output device, and (5) the
magnification factor to apply.
In response to the page number prompt, if you are using the plain
format with no tricks, just type the decimal integer page number where
you want translation to start. Actually, however, DVIDOC, will accept
up to ten fields separated by periods. The fields may be integers or
asterisks, and DVIDOC looks for the first page in the dvi file that
has counter values that meet this specification. Integers must match
exactly, and the asterisks are ``wild cards.''
The resolutions should be specified as explicit ratios of integers,
such as ``10/1'' for 10 characters per inch.
The magnification should be 1000 times the fraction you choose. Thus,
a magnification of 2000 means increase all dimension by a factor of
two.
The last three prompts should be answered in the default if you are
using docmac.
SHAR_EOF
fi # end of overwriting check
if test -f 'dvidoc.web'
then
echo shar: will not over-write existing file "'dvidoc.web'"
else
cat << \SHAR_EOF > 'dvidoc.web'
% This is DVIDOC, a TeX device driver for text files. It was written
% at OSU in April, 1983, by modifying the TeX utility DVItype.
% Here is TeX material that gets inserted after \input webhdr
\def\hang{\hangindent 3em\indent\ignorespace}
\def\TeX{T\hbox{\hskip-.1667em\lower.424ex\hbox{E}\hskip-.125em X}}
\font\ninerm=cmr9
\let\mc=\ninerm % medium caps for names like PASCAL
\def\PASCAL{{\mc PASCAL}}
\def\(#1){} % this is used to make module names sort themselves better
\def\9#1{} % this is used for sort keys in the index
\def\title{DVIDOC}
\def\contentspagenumber{1}
\def\topofcontents{\null
\def\titlepage{F} % include headline on the contents page
\def\rheader{\mainfont\hfil \contentspagenumber}
\vfill
\ctrline{\titlefont The {\ttitlefont DVIDOC} processor}
\vskip 15pt
\ctrline{(Version 1, April 1983)}
\vfill}
\def\botofcontents{\vfill
\ctrline{\hsize 5in\baselineskip9pt
\vbox{\ninerm\noindent
`\TeX' is a
trademark of the American Mathematical Society.}}}
\setcount0=\contentspagenumber \advcount0 by 1
@* Introduction.
The \.{DVIDOC} utility program reads binary device-independent (``\.{DVI}'')
files that are produced by document compilers such as \TeX, and
approximates the intended document as a text file suitable for typing at
a terminal or on a line printer.
This program is based on the program \.{DVItype}, which was written by
Donald Knuth and David Fuchs.
It contained a great deal of code checking for malformed \.{DVI}
files. Most of that code remains in \.{DVIDOC}, not because it is
important (we trust TeX) to produce correct \.{DVI} files), but
because is was easier not to disturb the logic in modifying
\.{DVItype} to produce \.{DVIDOC}.
The |banner| string defined here should be changed whenever \.{DVIDOC}
gets modified.
@d banner=='This is DVIDOC, Version 1' {printed when the program starts}
@ Unlike the programs distributed with \TeX, which are written in a
least-common-denominator Pascal that runs on no machine, this program
is written to run on TOPS-20 using Rutgers Pascal. Nevertheless, all
places where nonstandard constructions are used have been listed in
the index under ``system dependencies.''
@!@^system dependencies@>
One of the extensions to standard \PASCAL\ that we shall deal with is the
ability to move to a random place in a binary file; another is to
determine the length of a binary file.
Another extension is to use a default |case| as in \.{TANGLE}, \.{WEAVE},
etc.
@d othercases == others: {default for cases not listed explicitly}
@d endcases == @+end {follows the default case in an extended |case| statement}
@f othercases == else
@f endcases == end
@ The binary input comes from |dvi_file|, and the document is written
on the file |doc_file|
Their definitions in the |program| statement indicate that
they should use an existing version and a new version, respectively.
|term_in| and |term_out| are used throughout this program as files for
dialog with the user. These are associated by macro with the file
|tty|, and are retained as a concession to portability.
@^system dependencies@>
@d term_in==tty
@d term_out==tty
@p program DVIDOC(@!dvi_file:-,@!doc_file:+);
label @<Labels in the outer block@>@/
const @<Constants in the outer block@>@/
type @<Types in the outer block@>@/
var@?@<Globals in the outer block@>@/
procedure initialize; {this procedure gets things started properly}
var i:integer; {loop index for initializations}
begin @/
@<Set initial values@>@/
end;
@ If the program has to stop prematurely, it goes to the
`|final_end|'. Another label, |done|, is used when stopping normally.
@d final_end=9999 {label for the end of it all}
@d done=30 {go here when finished with a subtask}
@<Labels...@>=final_end,done;
@ The following parameters can be changed at compile time to extend or
reduce \.{DVIDOC}'s capacity.
@<Constants...@>=
@!max_fonts=100; {maximum number of distinct fonts per \.{DVI} file}
@!max_widths=10000; {maximum number of different characters among all fonts}
@!terminal_line_length=150; {maximum number of characters input in a single
line of input from the terminal}
@!stack_size=100; {\.{DVI} files shouldn't |push| beyond this depth}
@!name_size=1000; {total length of all font file names}
@!name_length=50; {a file name shouldn't be longer than this}
@!page_width_max=132; {maximum number of characters per line in the document}
@!page_length_max=88; {maximum number of lines per page in the document}
@ Here are some macros for common programming idioms.
@d incr(#) == #:=#+1 {increase a variable by unity}
@d decr(#) == #:=#-1 {decrease a variable by unity}
@d do_nothing == {empty statement}
@ If the \.{DVI} file is badly malformed, the whole process must be aborted;
\.{DVIDOC} will give up, after issuing an error message about the symptoms
that were noticed.
Such errors might be discovered inside of subroutines inside of subroutines,
so a procedure called |jump_out| has been introduced. This procedure, which
simply transfers control to the label |final_end| at the end of the program,
contains the only non-local |goto| statement in \.{DVIDOC}.
@^system dependencies@>
@d abort(#)==begin write(term_out,' ',#); jump_out;
end
@d bad_dvi(#)==abort('Bad DVI file: ',#,'!')
@.Bad DVI file@>
@p procedure jump_out;
begin goto final_end;
end;
@* The character set.
Like all programs written with the \.{WEB} system, \.{DVIDOC} can be
used with any character set. But it uses ascii code internally, because
the programming for portable input-output is easier when a fixed internal
code is used, and because \.{DVI} files use ascii code for file names
and certain other strings.
The next few modules of \.{DVIDOC} have therefore been copied from the
analogous ones in the \.{WEB} system routines. They have been considerably
simplified, since \.{DVIDOC} need not deal with the controversial
ascii codes less than @'40. If such codes appear in the \.{DVI} file,
they will be printed as question marks.
@<Types...@>=
@!ascii_code=" ".."~"; {a subrange of the integers}
@ The original \PASCAL\ compiler was designed in the late 60s, when six-bit
character sets were common, so it did not make provision for lower case
letters. Nowadays, of course, we need to deal with both upper and lower case
alphabets in a convenient way, especially in a program like \.{DVIDOC}.
So we shall assume that the \PASCAL\ system being used for \.{DVIDOC}
has a character set containing at least the standard visible characters
of ascii code (|"!"| through |"~"|).
Some \PASCAL\ compilers use the original name |char| for the data type
associated with the characters in text files, while other \PASCAL s
consider |char| to be a 64-element subrange of a larger data type that has
some other name. In order to accommodate this difference, we shall use
the name |text_char| to stand for the data type of the characters in the
output file. We shall also assume that |text_char| consists of
the elements |chr(first_text_char)| through |chr(last_text_char)|,
inclusive. The following definitions should be adjusted if necessary.
@^system dependencies@>
@d text_char == char {the data type of characters in text files}
@d first_text_char=0 {ordinal number of the smallest element of |text_char|}
@d last_text_char=127 {ordinal number of the largest element of |text_char|}
@<Types...@>=
@!text_file=packed file of text_char;
@ The \.{DVIDOC} processor converts between ascii code and
the user's external character set by means of arrays |xord| and |xchr|
that are analogous to \PASCAL's |ord| and |chr| functions.
@<Globals...@>=
@!xord: array [text_char] of ascii_code;
{specifies conversion of input characters}
@!xchr: array [0..255] of text_char;
{specifies conversion of output characters}
@ Under our assumption that the visible characters of standard ascii are
all present, the following assignment statements initialize the
|xchr| array properly, without needing any system-dependent changes.
@<Set init...@>=
for i:=0 to @'37 do xchr[i]:='?';
xchr[@'40]:=' ';
xchr[@'41]:='!';
xchr[@'42]:='"';
xchr[@'43]:='#';
xchr[@'44]:='$';
xchr[@'45]:='%';
xchr[@'46]:='&';
xchr[@'47]:='''';@/
xchr[@'50]:='(';
xchr[@'51]:=')';
xchr[@'52]:='*';
xchr[@'53]:='+';
xchr[@'54]:=',';
xchr[@'55]:='-';
xchr[@'56]:='.';
xchr[@'57]:='/';@/
xchr[@'60]:='0';
xchr[@'61]:='1';
xchr[@'62]:='2';
xchr[@'63]:='3';
xchr[@'64]:='4';
xchr[@'65]:='5';
xchr[@'66]:='6';
xchr[@'67]:='7';@/
xchr[@'70]:='8';
xchr[@'71]:='9';
xchr[@'72]:=':';
xchr[@'73]:=';';
xchr[@'74]:='<';
xchr[@'75]:='=';
xchr[@'76]:='>';
xchr[@'77]:='?';@/
xchr[@'100]:='@@';
xchr[@'101]:='A';
xchr[@'102]:='B';
xchr[@'103]:='C';
xchr[@'104]:='D';
xchr[@'105]:='E';
xchr[@'106]:='F';
xchr[@'107]:='G';@/
xchr[@'110]:='H';
xchr[@'111]:='I';
xchr[@'112]:='J';
xchr[@'113]:='K';
xchr[@'114]:='L';
xchr[@'115]:='M';
xchr[@'116]:='N';
xchr[@'117]:='O';@/
xchr[@'120]:='P';
xchr[@'121]:='Q';
xchr[@'122]:='R';
xchr[@'123]:='S';
xchr[@'124]:='T';
xchr[@'125]:='U';
xchr[@'126]:='V';
xchr[@'127]:='W';@/
xchr[@'130]:='X';
xchr[@'131]:='Y';
xchr[@'132]:='Z';
xchr[@'133]:='[';
xchr[@'134]:='\';
xchr[@'135]:=']';
xchr[@'136]:='^';
xchr[@'137]:='_';@/
xchr[@'140]:='`';
xchr[@'141]:='a';
xchr[@'142]:='b';
xchr[@'143]:='c';
xchr[@'144]:='d';
xchr[@'145]:='e';
xchr[@'146]:='f';
xchr[@'147]:='g';@/
xchr[@'150]:='h';
xchr[@'151]:='i';
xchr[@'152]:='j';
xchr[@'153]:='k';
xchr[@'154]:='l';
xchr[@'155]:='m';
xchr[@'156]:='n';
xchr[@'157]:='o';@/
xchr[@'160]:='p';
xchr[@'161]:='q';
xchr[@'162]:='r';
xchr[@'163]:='s';
xchr[@'164]:='t';
xchr[@'165]:='u';
xchr[@'166]:='v';
xchr[@'167]:='w';@/
xchr[@'170]:='x';
xchr[@'171]:='y';
xchr[@'172]:='z';
xchr[@'173]:='{';
xchr[@'174]:='|';
xchr[@'175]:='}';
xchr[@'176]:='~';
for i:=@'177 to 255 do xchr[i]:='?';
@ The following system-independent code makes the |xord| array contain a
suitable inverse to the information in |xchr|.
@<Set init...@>=
for i:=first_text_char to last_text_char do xord[chr(i)]:=@'40;
for i:=" " to "~" do xord[xchr[i]]:=i;
@* Device-independent file format.
The device-independent file format is described in the \.{DVItype}
documentation.
When \.{DVIDOC} "typesets" a character, it simply puts its ascii code
into the document file in the proper place according to the rounding of
|h| and |v| to whole character positions. It may, of course, obliterate
a character previously stored in the same position. Especially if a
symbol font is being used, the ascii code may print ultimately as an
entirely different character than the one the document designer originally
intended. For \.{DVIDOC} to produce more than a rough approximation to
the intended document, fonts need to be chosen very carefully.
@ @d set_char_0=0 {typeset character 0 and move right}
@d set1=128 {typeset a character and move right}
@d set_rule=132 {typeset a rule and move right}
@d put1=133 {typeset a character}
@d put_rule=137 {typeset a rule}
@d nop=138 {no operation}
@d bop=139 {beginning of page}
@d eop=140 {ending of page}
@d push=141 {save the current positions}
@d pop=142 {restore previous positions}
@d right1=143 {move right}
@d w0=147 {move right by |w|}
@d w1=148 {move right and set |w|}
@d x0=152 {move right by |x|}
@d x1=153 {move right and set |x|}
@d down1=157 {move down}
@d y0=161 {move down by |y|}
@d y1=162 {move down and set |y|}
@d z0=166 {move down by |z|}
@d z1=167 {move down and set |z|}
@d fnt_num_0=171 {set current font to 0}
@d fnt1=235 {set current font}
@d xxx1=239 {extension to \.{DVI} primitives}
@d xxx4=242 {potentially long extension to \.{DVI} primitives}
@d fnt_def1=243 {define the meaning of a font number}
@d pre=247 {preamble}
@d post=248 {postamble beginning}
@d post_post=249 {postamble ending}
@d undefined_commands==250,251,252,253,254,255
@d id_byte=2 {identifies the kind of \.{DVI} files described here}
@* Input from binary files.
We have seen that a \.{DVI} file is a sequence of 8-bit bytes. The bytes
appear physically in what is called a `|packed file of 0..255|'
in \PASCAL\ lingo.
Packing is system dependent, and many \PASCAL\ systems fail to implement
such files in a sensible way (at least, from the viewpoint of producing
good production software). For example, some systems treat all
byte-oriented files as text, looking for end-of-line marks and such
things. Therefore some system-dependent code is often needed to deal with
binary files, even though most of the program in this section of
\.{DVIDOC} is written in standard \PASCAL.
@^system dependencies@>
We shall stick to simple \PASCAL\ in this program, for reasons of clarity,
even if such simplicity is sometimes unrealistic.
@<Types...@>=
@!eight_bits=0..255; {unsigned one-byte quantity}
@!byte_file=packed file of eight_bits; {files that contain binary data}
@ The program deals with two binary file variables: |dvi_file| is the main
input file that we are translating into symbolic form, and |tfm_file| is
the current font metric file from which character-width information is
being read.
@<Glob...@>=
@!dvi_file:byte_file; {the stuff we are \.{DVI}typing}
@!tfm_file:byte_file; {a font metric file}
@ To prepare these files for input, we |reset| them. An extension of
\PASCAL\ is needed in the case of |tfm_file|, since we want to associate
it with external files whose names are specified dynamically (i.e., not
known at compile time). The following code assumes that `|reset(f,s)|'
does this, when |f| is a file variable and |s| is a string variable that
specifies the file name. If |eof(f)| is true immediately after
|reset(f,s)| has acted, we assume that no file named |s| is accessible.
Another \PASCAL\ extention, a flag in the third parameter to |reset|,
is used to indicate that these two files are
stored externally with four 8-bit bytes per 36-bit word.
@^system dependencies@>
@p procedure open_dvi_file; {prepares to read packed bytes in |dvi_file|}
begin reset(dvi_file,'','/B:8');
cur_loc:=0;
end;
@#
procedure open_tfm_file; {prepares to read packed bytes in |tfm_file|}
begin reset(tfm_file,cur_name,'/B:8');
end;
@ If you looked carefully at the preceding code, you probably asked,
``What are |cur_loc| and |cur_name|?'' Good question. They're global
variables: |cur_loc| is the number of the byte about to be read next from
|dvi_file|, and |cur_name| is a string variable that will be set to the
current font metric file name before |open_tfm_file| is called.
@<Glob...@>=
@!cur_loc:integer; {where we are about to look, in |dvi_file|}
@!cur_name:packed array[1..name_length] of char; {external name,
with no lower case letters}
@ It turns out to be convenient to read four bytes at a time, when we are
inputting from \.{TFM} files. The input goes into global variables
|b0|, |b1|, |b2|, and |b3|, with |b0| getting the first byte and |b3|
the fourth.
@<Glob...@>=
@!b0,@!b1,@!b2,@!b3: eight_bits; {four bytes input at once}
@ The |read_tfm_word| procedure sets |b0| through |b3| to the next
four bytes in the current \.{TFM} file.
@^system dependencies@>
@p procedure read_tfm_word;
begin read(tfm_file,b0); read(tfm_file,b1);
read(tfm_file,b2); read(tfm_file,b3);
end;
@ We shall use another set of simple functions to read the next byte or
bytes from |dvi_file|. There are seven possibilities, each of which is
treated as a separate function in order to minimize the overhead for
subroutine calls.
@^system dependencies@>
@p function get_byte:integer; {returns the next byte, unsigned}
var b:eight_bits;
begin if eof(dvi_file) then get_byte:=0
else begin read(dvi_file,b); incr(cur_loc); get_byte:=b;
end;
end;
@#
function signed_byte:integer; {returns the next byte, signed}
var b:eight_bits;
begin read(dvi_file,b); incr(cur_loc);
if b<128 then signed_byte:=b @+ else signed_byte:=b-256;
end;
@#
function get_two_bytes:integer; {returns the next two bytes, unsigned}
var a,@!b:eight_bits;
begin read(dvi_file,a); read(dvi_file,b);
cur_loc:=cur_loc+2;
get_two_bytes:=a*256+b;
end;
@#
function signed_pair:integer; {returns the next two bytes, signed}
var a,@!b:eight_bits;
begin read(dvi_file,a); read(dvi_file,b);
cur_loc:=cur_loc+2;
if a<128 then signed_pair:=a*256+b
else signed_pair:=(a-256)*256+b;
end;
@#
function get_three_bytes:integer; {returns the next three bytes, unsigned}
var a,@!b,@!c:eight_bits;
begin read(dvi_file,a); read(dvi_file,b); read(dvi_file,c);
cur_loc:=cur_loc+3;
get_three_bytes:=(a*256+b)*256+c;
end;
@#
function signed_trio:integer; {returns the next three bytes, signed}
var a,@!b,@!c:eight_bits;
begin read(dvi_file,a); read(dvi_file,b); read(dvi_file,c);
cur_loc:=cur_loc+3;
if a<128 then signed_trio:=(a*256+b)*256+c
else signed_trio:=((a-256)*256+b)*256+c;
end;
@#
function signed_quad:integer; {returns the next four bytes, signed}
var a,@!b,@!c,@!d:eight_bits;
begin read(dvi_file,a); read(dvi_file,b); read(dvi_file,c); read(dvi_file,d);
cur_loc:=cur_loc+4;
if a<128 then signed_quad:=((a*256+b)*256+c)*256+d
else signed_quad:=(((a-256)*256+b)*256+c)*256+d;
end;
@ Finally we come to the routines that do random file access.
The driver program below needs two such routines: |dvi_length| should
compute the total number of bytes in |dvi_file|, possibly also
causing |eof(dvi_file)| to be true; and |move_to_byte(n)|
should position |dvi_file| so that the next |get_byte| will read byte |n|,
starting with |n=0| for the first byte in the file.
@^system dependencies@>
Such routines are, of course, highly system dependent. They are implemented
here in terms of two assumed system routines called |set_pos| and |cur_pos|.
The call |set_pos(f,n)| moves to item |n| in file |f|, unless |n| is
negative or larger than the total number of items in |f|; in the latter
case, |set_pos(f,n)| moves to the end of file |f|.
The call |cur_pos(f)| gives the total number of items in |f|, if
|eof(f)| is true; we use |cur_pos| only in such a situation.
@p function dvi_length:integer;
begin set_pos(dvi_file,-1); dvi_length:=cur_pos(dvi_file);
end;
@#
procedure move_to_byte(n:integer);
begin set_pos(dvi_file,n); cur_loc:=n;
end;
@* Reading the font information.
\.{DVI} file format does not include information about character widths, since
that would tend to make the files a lot longer. But a program that reads
a \.{DVI} file is supposed to know the widths of the characters that appear
in \\{set\_char} commands. Therefore \.{DVIDOC} looks at the font metric
(\.{TFM}) files for the fonts that are involved.
@.TFM {\rm files}@>
@ For purposes of this program, we need to know only two things about a
given character |c| in a given font |f|: (1)@@Is |c| a legal character
in@@|f|? (2)@@If so, what is the width of |c|? We also need to know the
symbolic name of each font, so it can be printed out, and we need to know
the approximate size of inter-word spaces in each font.
The answers to these questions appear implicitly in the following data
structures. The current number of known fonts is |nf|. Each known font has
an internal number |f|, where |0<=f<nf|; the external number of this font,
i.e., its font identification number in the \.{DVI} file, is
|font_num[f]|, and the external name of this font is the string that
occupies positions |font_name[f]| through |font_name[f+1]-1| of the array
|names|. The latter array consists of |ascii_code| characters, and
|font_name[nf]| is its first unoccupied position. A horizontal motion
less than |font_space[f]| will be treated as a `kern'.
The
legal characters run from |font_bc[f]| to |font_ec[f]|, inclusive; more
precisely, a given character |c| is valid in font |f| if and only if
|font_bc[f]<=c<=font_ec[f]| and |char_width(f)(c)<>invalid_width|.
(Exception: If |font_ec[f]=256|, all characters |c>=256| are valid and have
the same width |char_width(f)(256)|.)
@^oriental characters@>@^Chinese characters@>@^Japanese characters@>
Finally, |char_width(f)(c)=width[width_base[f]+c]|, and |width_ptr| is the
first unused position of the |width| array.
@d char_width_end(#)==#]
@d char_width(#)==width[width_base[#]+char_width_end
@d invalid_width==@'17777777777
@<Glob...@>=
@!font_num:array [0..max_fonts] of integer; {external font numbers}
@!font_name:array [0..max_fonts] of 0..name_size; {starting positions
of external font names}
@!names:array [0..name_size] of ascii_code; {characters of names}
@!font_check_sum:array [0..max_fonts] of integer; {check sums}
@!font_scaled_size:array [0..max_fonts] of integer; {scale factors}
@!font_design_size:array [0..max_fonts] of integer; {design sizes}
@!font_space:array [0..max_fonts] of integer; {boundary between ``small''
and ``large'' spaces}
@!font_bc:array [0..max_fonts] of integer; {beginning characters in fonts}
@!font_ec:array [0..max_fonts] of integer; {ending characters in fonts}
@!width_base:array [0..max_fonts] of integer; {index into |width| table}
@!width:array [0..max_widths] of integer; {character widths, in \.{DVI} units}
@!nf:0..max_fonts; {the number of known fonts}
@!width_ptr:0..max_widths; {the number of known character widths}
@ @<Set init...@>=
nf:=0; width_ptr:=0; font_name[0]:=0;
@ It is, of course, a simple matter to print the name of a given font.
@p procedure print_font(@!f:integer); {|f| is an internal font number}
var k:0..name_size; {index into |names|}
begin if f=nf then write(term_out,'UNDEFINED!')
@.UNDEFINED@>
else begin for k:=font_name[f] to font_name[f+1]-1 do
write(term_out,xchr[names[k]]);
end;
end;
@ An auxiliary array |in_width| is used to hold the widths as they are
input. The global variable |tfm_check_sum| is set to the check sum that
appears in the current \.{TFM} file.
@<Glob...@>=
@!in_width:array[0..255] of integer; {\.{TFM} width data in \.{DVI} units}
@!tfm_check_sum:integer; {check sum found in |tfm_file|}
@ Here is a procedure that absorbs the necessary information from a
\.{TFM} file, assuming that the file has just been successfully reset
so that we are ready to read its first byte. (A complete description of
\.{TFM} file format appears in the documentation of \.{TFtoPL} and will
not be repeated here.) The procedure does not check the \.{TFM} file
for validity, nor does it give explicit information about what is
wrong with a \.{TFM} file that proves to be invalid; \.{DVI}-reading
programs need not do this, since \.{TFM} files are almost always valid,
and since the \.{TFtoPL} utility program has been specifically designed
to diagnose \.{TFM} errors. The procedure simply returns |false| if it
detects anything amiss in the \.{TFM} data.
There is a parameter, |z|, which represents the scaling factor being
used to compute the font dimensions; it must be in the range $0<z<2^{27}$.
@p function in_TFM(@!z:integer):boolean; {input \.{TFM} data or return |false|}
label 9997, {go here when the format is bad}
9998, {go here when the information cannot be loaded}
9999; {go here to exit}
var k:integer; {index for loops}
@!lh:integer; {length of the header data, in four-byte words}
@!nw:integer; {number of words in the width table}
@!wp:0..max_widths; {new value of |width_ptr| after successful input}
@!alpha,@!beta:integer; {quantities used in the scaling computation}
begin @<Read past the header data; |goto 9997| if there is a problem@>;
@<Store character-width indices at the end of the |width| table@>;
@<Read and convert the width values, setting up the |in_width| table@>;
@<Move the widths from |in_width| to |width|, and append |pixel_width| values@>;
width_ptr:=wp; in_TFM:=true; goto 9999;
9997: write_ln(term_out,'---not loaded, TFM file is bad');
@.TFM file is bad@>
9998: in_TFM:=false;
9999: end;
@ @<Read past the header...@>=
read_tfm_word; lh:=b2*256+b3;
read_tfm_word; font_bc[nf]:=b0*256+b1; font_ec[nf]:=b2*256+b3;
if font_ec[nf]<font_bc[nf] then font_bc[nf]:=font_ec[nf]+1;
if width_ptr+font_ec[nf]-font_bc[nf]+1>max_widths then
begin write_ln(term_out,'---not loaded, DVIDOC needs larger width table');
@.DVIDOC needs larger...@>
goto 9998;
end;
wp:=width_ptr+font_ec[nf]-font_bc[nf]+1;
read_tfm_word; nw:=b0*256+b1;
if (nw=0)or(nw>256) then goto 9997;
for k:=1 to 3+lh do
begin if eof(tfm_file) then goto 9997;
read_tfm_word;
if k=4 then
if b0<128 then tfm_check_sum:=((b0*256+b1)*256+b2)*256+b3
else tfm_check_sum:=(((b0-256)*256+b1)*256+b2)*256+b3;
end;
@ @<Store character-width indices...@>=
if wp>0 then for k:=width_ptr to wp-1 do
begin read_tfm_word;
if b0>nw then goto 9997;
width[k]:=b0;
end;
@ The most important part of |in_TFM| is the width computation, which
involves multiplying the relative widths in the \.{TFM} file by the
scaling factor in the \.{DVI} file. This fixed-point multiplication
must be done with precisely the same accuracy by all \.{DVI}-reading programs,
in order to validate the assumptions made by \.{DVI}-writing programs
like \TeX82.
Let us therefore summarize what needs to be done. Each width in a \.{TFM}
file appears as a four-byte quantity called a |fix_word|. A |fix_word|
whose respective bytes are $(a,b,c,d)$ represents the number
$$x=\left\{\vcenter{\halign{\lft{$#$,}\qquad&if \lft{$#$}\cr
b\cdot2^{-4}+c\cdot2^{-12}+d\cdot2^{-20}&a=0;\cr
-16+b\cdot2^{-4}+c\cdot2^{-12}+d\cdot2^{-20}&a=255.\cr}}\right.$$
(No other choices of $a$ are allowed, since the magnitude of a \.{TFM}
dimension must be less than 16.) We want to multiply this quantity by the
integer@@|z|, which is known to be less then $2^{27}$. Let $\alpha=16z$.
If $|z|<2^{23}$, the individual multiplications $b\cdot z$, $c\cdot z$,
$d\cdot z$ cannot overflow; otherwise we will divide |z| by 2, 4, 8, or
16, to obtain a multiplier less than $2^{23}$, and we can compensate for
this later. If |z| has thereby been replaced by $|z|^\prime=|z|/2^e$, let
$\beta=2^{4-e}$; we shall compute
$$\lfloor(b+c\cdot2^{-8}+d\cdot2^{-16})\,z^\prime/\beta\rfloor$$ if $a=0$,
or the same quantity minus $\alpha$ if $a=255$. This calculation must be
done exactly, for the reasons stated above; the following program does the
job in a system-independent way, assuming that arithmetic is exact on
numbers less than $2^{31}$ in magnitude.
@<Read and convert the width values...@>=
@<Replace |z| by $|z|^\prime$ and compute $\alpha,\beta$@>;
for k:=0 to nw-1 do
begin read_tfm_word;
in_width[k]:=(((((b3*z)div@'400)+(b2*z))div@'400)+(b1*z))div beta;
if b0>0 then if b0<255 then goto 9997
else in_width[k]:=in_width[k]-alpha;
end
@ @<Replace |z|...@>=
begin alpha:=16*z; beta:=16;
while z>=@'40000000 do
begin z:=z div 2; beta:=beta div 2;
end;
end
@ A \.{DVI}-reading program usually works with font files instead of
\.{TFM} files, so \.{DVIDOC} is atypical in that respect. Font files
should, however, contain exactly the same character width data that is
found in the corresponding \.{TFM}s. In addition, font files usually
also contain the widths of characters in pixels, since the device-independent
character widths of \.{TFM} files are generally not perfect multiples of
pixels.
The |pixel_width| array contains this information; when |width[k]| is the
device-independent width of some character in \.{DVI} units, |pixel_width[k]|
is the corresponding width of that character in an actual font.
The macro |char_pixel_width| is set up to be analogous to |char_width|.
@d char_pixel_width(#)==pixel_width[width_base[#]+char_width_end
@<Glob...@>=
@!pixel_width:array[0..max_widths] of integer; {actual character widths,
in pixels}
@!horiz_conv:real; {converts \.{DVI} units to horizontal pixels}
@!vert_conv:real; {converts \.{DVI} units to vertical pixels}
@!true_horiz_conv:real; {converts unmagnified \.{DVI} units to pixels}
@!true_vert_conv:real; {converts unmagnified \.{DVI} units to pixels}
@!numerator,@!denominator:integer; {stated conversion ratio}
@!mag:integer; {magnification factor times 1000}
@ The following code computes pixel widths by simply rounding the \.{TFM}
widths to the nearest integer number of pixels, based on the conversion factor
|horiz_conv| that converts \.{DVI} units to pixels.
@d horiz_pixel_round(#)==trunc(horiz_conv*(#)+0.5)
@d vert_pixel_round(#)==trunc(vert_conv*(#)+0.5)
@<Move the widths from |in_width| to |width|, and append |pixel_width| values@>=
width_base[nf]:=width_ptr-font_bc[nf];
if wp>0 then for k:=width_ptr to wp-1 do
begin width[k]:=in_width[width[k]];
pixel_width[k]:=horiz_pixel_round(width[k]);
end
@* Optional modes of output.
\.{DVIDOC} output will vary depending on some
options that the user must specify: The typeout can be confined to a
restricted subset of the pages by specifying the desired starting page and
the maximum number of pages. Furthermore there is an option to specify the
horizontal and vertical
resolution of the printer or display; and there is an option to override the
magnification factor that is stated in the \.{DVI} file.
The starting page is specified by giving a sequence of 1 to 10 numbers or
asterisks separated by dots. For example, the specification `\.{1.*.-5}'
can be used to refer to a page output by \TeX\ when $\.{\\count0}=1$
and $\.{\\count2}=-5$. (Recall that |bop| commands in a \.{DVI} file
are followed by ten `count' values.) An asterisk matches any number,
so the `\.*' in `\.{1.*.-5}' means that \.{\\count1} is ignored when
specifying the first page. If several pages match the given specification,
\.{DVIDOC} will begin with the earliest such page in the file. The
default specification `\.*' (which matches all pages) therefore denotes
the page at the beginning of the file.
When \.{DVIDOC} begins, it engages the user in a brief dialog so that the
options will be specified. This part of \.{DVIDOC} requires nonstandard
\PASCAL\ constructions to handle the online interaction.
@^system dependencies@>
@<Glob...@>=
@!max_pages:integer; {at most this many |bop..eop| pages will be printed}
@!horiz_resolution:real; {pixels per inch}
@!vert_resolution:real; {pixels per inch}
@!new_mag:integer; {if positive, overrides the postamble's magnification}
@ The starting page specification is recorded in two global arrays called
|start_count| and |start_there|. For example, `\.{1.*.-5}' is represented
by |start_there[0]=true|, |start_count[0]=1|, |start_there[1]=false|,
|start_there[2]=true|, |start_count[2]=-5|.
We also set |start_vals=2|, to indicate that count 2 was the last one
mentioned. The other values of |start_count| and |start_there| are not
important, in this example.
@<Glob...@>=
@!start_count:array[0..9] of integer; {count values to select starting page}
@!start_there:array[0..9] of boolean; {is the |start_count| value relevant?}
@!start_vals:0..9; {the last count considered significant}
@!count:array[0..9] of integer; {the count values on the current page}
@ @<Set init...@>=
max_pages:=1000000; start_vals:=0; start_there[0]:=false;
@ Here is a simple subroutine that tests if the current page might be the
starting page.
@p function start_match:boolean; {does |count| match the starting spec?}
var k:0..9; {loop index}
@!match:boolean; {does everything match so far?}
begin match:=true;
for k:=0 to start_vals do
if start_there[k]and(start_count[k]<>count[k]) then match:=false;
start_match:=match;
end;
@ The |input_ln| routine waits for the user to type a line at his or her
terminal; then it puts ascii-code equivalents for the characters on that line
into the |buffer| array.
@^system dependencies@>
@<Glob...@>=
@!buffer:array[0..terminal_line_length] of ascii_code;
@ Since the terminal is being used for both input and output, some systems
need a special routine to make sure that the user can see a prompt message
before waiting for input based on that message. (Otherwise the message
may just be sitting in a hidden buffer somewhere, and the user will have
no idea what the program is waiting for.) We shall call a system-dependent
subroutine |update_terminal| in order to avoid this problem.
@^system dependencies@>
@d update_terminal == break(term_out) {empty the terminal output buffer}
@ During the dialog, \.{DVIDOC} will treat the first blank space in a
line as the end of that line. Therefore |input_ln| makes sure that there
is always at least one blank space in |buffer|.
@^system dependencies@>
@p procedure input_ln; {inputs a line from the terminal}
var k:0..terminal_line_length;
begin update_terminal; reset(term_in);
if eoln(term_in) then read_ln(term_in);
k:=0;
while (k<terminal_line_length)and not eoln(term_in) do
begin buffer[k]:=xord[term_in^]; incr(k); get(term_in);
end;
buffer[k]:=" ";
end;
@ The global variable |buf_ptr| is used while scanning each line of input;
it points to the first unread character in |buffer|.
@<Glob...@>=
@!buf_ptr:0..terminal_line_length; {the number of characters read}
@ Here is a routine that scans a (possibly signed) integer and computes
the decimal value. If no decimal integer starts at |buf_ptr|, the
value 0 is returned. The integer should be less than $2^{31}$ in
absolute value.
@p function get_integer:integer;
var x:integer; {accumulates the value}
@!negative:boolean; {should the value be negated?}
begin if buffer[buf_ptr]="-" then
begin negative:=true; incr(buf_ptr);
end
else negative:=false;
x:=0;
while (buffer[buf_ptr]>="0")and(buffer[buf_ptr]<="9") do
begin x:=10*x+buffer[buf_ptr]-"0"; incr(buf_ptr);
end;
if negative then get_integer:=-x @+ else get_integer:=x;
end;
@ The selected options are put into global variables by the |dialog|
procedure, which is called just as \.{DVIDOC} begins.
@^system dependencies@>
@p procedure dialog;
label 1,2,3,4,5;
var k:integer; {loop variable}
begin rewrite(term_out); {prepare the terminal for output}
write_ln(term_out,banner);
@<Determine the desired |start_count| values@>;
@<Determine the desired |max_pages|@>;
@<Determine the desired |horiz_resolution|@>;
@<Determine the desired |vert_resolution|@>;
@<Determine the desired |new_mag|@>;
end;
@ @<Determine the desired |start...@>=
2: write(term_out,'Starting page (default=*): ');
start_vals:=0; start_there[0]:=false;
input_ln; buf_ptr:=0; k:=0;
if buffer[0]<>" " then
repeat if buffer[buf_ptr]="*" then
begin start_there[k]:=false; incr(buf_ptr);
end
else begin start_there[k]:=true; start_count[k]:=get_integer;
end;
if (k<9)and(buffer[buf_ptr]=".") then
begin incr(k); incr(buf_ptr);
end
else if buffer[buf_ptr]=" " then start_vals:=k
else begin write(term_out,'Type, e.g., 1.*.-5 to specify the ');
write_ln(term_out,'first page with \count0=1, \count2=-5.');
goto 2;
end;
until start_vals=k
@ @<Determine the desired |max_pages|@>=
3: write(term_out,'Maximum number of pages (default=1000000): ');
max_pages:=1000000; input_ln; buf_ptr:=0;
if buffer[0]<>" " then
begin max_pages:=get_integer;
if max_pages<=0 then
begin write_ln(term_out,'Please type a positive number.');
goto 3;
end;
end
@ @<Determine the desired |horiz_resolution|@>=
1: write(term_out,'Horizontal resolution');
write(term_out,' in characters per inch (default=10/1): ');
horiz_resolution:=10.0; input_ln; buf_ptr:=0;
if buffer[0]<>" " then
begin k:=get_integer;
if (k>0)and(buffer[buf_ptr]="/")and
(buffer[buf_ptr+1]>"0")and(buffer[buf_ptr+1]<="9") then
begin incr(buf_ptr); horiz_resolution:=k/get_integer;
end
else begin write(term_out,'Type a ratio of positive integers;');
write_ln(term_out,' (1 character per mm would be 254/10).');
goto 1;
end;
end
@ @<Determine the desired |vert_resolution|@>=
4: write(term_out,'Vertical resolution');
write(term_out,' in lines per inch (default=6/1): ');
vert_resolution:=6.0; input_ln; buf_ptr:=0;
if buffer[0]<>" " then
begin k:=get_integer;
if (k>0)and(buffer[buf_ptr]="/")and
(buffer[buf_ptr+1]>"0")and(buffer[buf_ptr+1]<="9") then
begin incr(buf_ptr); vert_resolution:=k/get_integer;
end
else begin write(term_out,'Type a ratio of positive integers;');
write_ln(term_out,' (1 line per mm would be 254/10).');
goto 4;
end;
end
@ @<Determine the desired |new_mag|@>=
5: write(term_out,'New magnification (default=0 to keep the old one): ');
new_mag:=0; input_ln; buf_ptr:=0;
if buffer[0]<>" " then
if (buffer[0]>="0")and(buffer[0]<="9") then new_mag:=get_integer
else begin write(term_out,'Type a positive integer to override ');
write_ln(term_out,'the magnification in the DVI file.');
goto 5;
end
@* Defining fonts.
\.{DVIDOC} reads the postamble first and loads
all of the donts defined there; then it processes the pages. In this
case, a \\{fnt\_def} command should match a previous definition if and only
if the \\{fnt\_def} being processed is not in the postamble.
A global variable |in_postamble| is provided to tell whether we are
processing the postamble or not.
@<Glob...@>=
@!in_postamble:boolean; {are we reading the postamble?}
@ @<Set init...@>=
in_postamble:=false;
@ The following subroutine does the necessary things when a \\{fnt\_def}
command is being processed.
@p procedure define_font(@!e:integer); {|e| is an external font number}
var f:0..max_fonts;
@!p:integer; {length of the area/directory spec}
@!n:integer; {length of the font name proper}
@!c,@!q,@!d:integer; {check sum, scaled size, and design size}
@!r:0..name_length; {index into |cur_name|}
@!j,@!k:0..name_size; {indices into |names|}
@!mismatch:boolean; {do names disagree?}
begin if nf=max_fonts then abort('DVIDOC capacity exceeded (max fonts=',
max_fonts:0,')!');
@.DVIDOC capacity exceeded...@>
font_num[nf]:=e; f:=0;
while font_num[f]<>e do incr(f);
@<Read the font parameters into position for font |nf|, and
print the font name@>;
if in_postamble then
begin if f<nf then write_ln(term_out,'---this font was already defined!');
@.this font was already defined@>
end
else begin if f=nf then write_ln(term_out,'---this font wasn''t loaded before!');
@.this font wasn't loaded before@>
end;
if f=nf then @<Load the new font, unless there are problems@>
else @<Check that the current font definition matches the old one@>;
end;
@ @<Check that the current...@>=
begin if font_check_sum[f]<>c then
write_ln(term_out,'---check sum doesn''t match previous definition!');
@.check sum doesn't match@>
if font_scaled_size[f]<>q then
write_ln(term_out,'---scaled size doesn''t match previous definition!');
@.scaled size doesn't match@>
if font_design_size[f]<>d then
write_ln(term_out,'---design size doesn''t match previous definition!');
@.design size doesn't match@>
j:=font_name[f]; k:=font_name[nf]; mismatch:=false;
while j<font_name[f+1] do
begin if names[j]<>names[k] then mismatch:=true;
incr(j); incr(k);
end;
if k<>font_name[nf+1] then mismatch:=true;
if mismatch then write_ln(term_out,'---font name doesn''t match previous definition!');
@.font name doesn't match@>
write_ln(term_out)
end
@ @<Read the font parameters into position for font |nf|...@>=
c:=signed_quad; font_check_sum[nf]:=c;@/
q:=signed_quad; font_scaled_size[nf]:=q;@/
d:=signed_quad; font_design_size[nf]:=d;@/
p:=get_byte; n:=get_byte;
if font_name[nf]+n+p>name_size then
abort('DVIDOC capacity exceeded (name size=',name_size:0,')!');
SHAR_EOF
fi # end of overwriting check
# End of shell archive
exit 0
--
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Computers will never replace the Clayton Elwell
wastebasket when it comes to Elwell@Ohio-State.ARPA
streamlining office work. ...!cbosgd!osu-eddie!elwell
----------------------------------------------------------------------