\centerline{\bf Pira's Precursor}
\noindent
Pira (the Research Association for the
Paper \&\ Board, Printing, and
Packaging Industries)
is about to start publication of `Commentary'
which will cover the area of `Desktop Publishing'.

They have already published a `Precursor Issue',
which made quite interesting reading. Especially
relevant to \TeX\ was their definition of desktop publishing, namely:
``any system which allows someone --- using a desktop
terminal --- to produce a document of typeset or near-typeset quality\dots
It can run on a microcomputer or a large mainframe.''

Less agreeable are the enormous sums which it will
take to receive this twice quarterly (I think that means 8 times a year)
publication. First-year subscription is \quid350, although members of
Pira are elegible for a discount of \quid70, making it a mere \quid280.
I used to have this weird idea that electronic publication might
make things cheaper. Silly me.  It therefore comes as no real surprise
that ``The contents of Pira Desktop Publishing Commentary may not be
reproduced by any means without  the prior permission of the publisher in
writing''. I am relieved that I merely quote from the Precursor Issue,
and not the real thing. It is rather interesting how the idea of
emulating the Seybold Report mobilises money-spinning ideas.
Contact:
{\obeylines\parindent2em
Pira
Randalls Road
Leatherhead
Surrey KT22 7RU
0372 376161}


\rightline{\sl Malcolm W Clark}
\bigskip
\vfil
\centerline{\bf Bug}
\noindent
There is a bug in the current versions of \TeX.
It is a little esoteric, but qualified its
finder for a fairly handsome cheque from
Donald Knuth. Its finder was Donald Knuth himself:
 if you type a space after
a hyphen or dash, you do not get optimum line breaks.
If you look through the \TeX book, you will notice that
Knuth seldom (if ever) puts spaces after dashes. Which
may help to explain why it has taken so long to surface,
or to be recognised. In TUGboat, Knuth says that he
has sent details of the changes necessary to
all the main implementors, and that he expects a
new version to be available from those implementors
in the future.

\bigskip\vfil
\centerline{\bf TUGboat}
\noindent
There are several references in \TeX line to TUGboat.
TUGboat contains the communications of the
\TeX\ Users Group (TUG), and is published ``irregularly''
(about three times a year).  If you are seriously
interested in \TeX, you really ought to join TUG,
and therefore receive TUGboat.
Since it covers the whole field of \TeX\ endeavour
there is usually something for everyone. I personally
feel that it could increase its coverage of simple
or beginning \TeX, and afford to recap the current
position, just for those who don't know. However, besides
 detailed accounts
of ``how I implemented \TeX\ on the Lemon FAU-32,
despite overwhelming odds'', it includes topics of far
more general
interest. Naturally TUGboat covers \MF\ and {\tt WEB}.
As more \TeX\ related products come along, the
amount of advertising material has increased too.
I find this very useful, although I do find certain
US and Canadian advertisers a little reluctant to communicate with
Europe.
To join TUG, contact
{\obeylines\parindent2em
\TeX\ Users Group
PO Box 9506
Providence
RI 02940
USA
}

\bigskip\vfil
\centerline{\bf Mac\MFb}
\noindent
There is now an implementation of \MF\ for the Macintosh.
Victor Ostromoukhov has ported \MF\ to work on
any Mac with at least 512K of memory and 2 floppies.
It looks remarkably attractive. I have included
one of Victor's screen hardcopies in this \TeX line.
He says that it is NOT a commercial distribution, but
that he would like some ``reasonable participation in expenses''.
If you would like more information, contact
{\obeylines\parindent2em
Victor Ostromoukhov
25 Rue P\'eclet
75015 Paris
France
}

\bigskip\vfil
\centerline{\bf \LaTeX\ problems}
\noindent
The following problem has been observed on
an IBM pc clone running micro\TeX\ with \LaTeX.
The micro ``quite often gets locked and has to
be rebooted''. This can happen with
short or long files; the {\tt .log} file is
not available. After rebooting, the file seems to
be accepted without demur. The problem
has never been encountered with \TeX\ itself. Has anyone else encountered
similar problems?

\rightline{\sl Mark Bicknell}

\bigskip\vfil
\centerline{\bf More symbols for \TeX}
\noindent
Although \TeX\ has a bewilderingly large array of
special symbols and operators, inevitably there are
omissions. One such is a `three dot' accent,
analagous to |\dot| and |\ddot|. This is not
particularly difficult to provide, through the use
of |\mathchoice|. The main problem lies in finding
the correct gap between the new accent and the group it
accents, for each style. The use of |\mathcoice|
is rather expensive for \TeX, since it assiduously
calculates each of the four possibilities when it
is referenced, not knowing which one it will use.
The code looks something like this:
\def\dddot#1{
  \def\ddd{.\mkern-1.8mu.\mkern-1.8mu.}
\mathchoice
%displaystyle
  {\vbox{\offinterlineskip
  \halign{\hfil##\hfil\crcr
  $\smash{\displaystyle\ddd}$\crcr
  \noalign{\vskip0.4ex}
  $\displaystyle{#1}$\crcr}}}
%textstyle
  {\vbox{\offinterlineskip
  \halign{\hfil##\hfil\crcr
  $\smash{\textstyle\ddd}$\crcr
  \noalign{\vskip0.38ex}
  $\textstyle{#1}$\crcr}}}
%scriptstyle
  {\vbox{\offinterlineskip
   \halign{\hfil##\hfil\crcr
  $\smash{\scriptstyle\ddd}$\crcr
  \noalign{\vskip0.3ex}
  $\scriptstyle{#1}$\crcr}}}
%scriptscriptstyle
  {\vbox{\offinterlineskip
  \halign{\hfil##\hfil\crcr
  $\smash{\scriptscriptstyle\ddd}$\crcr
  \noalign{\vskip0.17ex}
  $\scriptscriptstyle{#1}$\crcr}}}}
\begintt
\def\dddot#1{
  \def\ddd{.\mkern-1.8mu.\mkern-1.8mu.}
\mathchoice
%displaystyle
  {\vbox{\offinterlineskip
  \halign{\hfil##\hfil\crcr
  $\smash{\displaystyle\ddd}$\crcr
  \noalign{\vskip0.4ex}%
  $\displaystyle{#1}$\crcr}}}
%textstyle
  {\vbox{\offinterlineskip
  \halign{\hfil##\hfil\crcr
  $\smash{\textstyle\ddd}$\crcr
  \noalign{\vskip0.38ex}
  $\textstyle{#1}$\crcr}}}
%scriptstyle
  {\vbox{\offinterlineskip
  \halign{\hfil##\hfil\crcr
  $\smash{\scriptstyle\ddd}$\crcr
  \noalign{\vskip0.3ex}
  $\scriptstyle{#1}$\crcr}}}
%scriptscriptstyle
  {\vbox{\offinterlineskip
  \halign{\hfil##\hfil\crcr
  $\smash{\scriptscriptstyle\ddd}$\crcr
  \noalign{\vskip0.17ex}
  $\scriptscriptstyle{#1}$\crcr}}}}
\endtt

Similarly, it is sometimes useful to be able to place
accents {\it under} a maths character. I did this
for `under tilde':
\def\ut#1{   \def\t{\char'176}
  \mathchoice
%displaystyle  
  {\vtop{\ialign{##\crcr
  $\hfil\displaystyle{#1}\hfil$\crcr\noalign
  {\nointerlineskip\vskip1pt}
  $\hfil\displaystyle\t\hfil$\crcr}}}  
%textstyle
  {\smash
  {\vtop{\ialign{##\crcr
  $\hfil\textstyle{#1}\hfil$\crcr\noalign
  {\nointerlineskip\vskip1pt}
  $\hfil\textstyle\t\hfil$\crcr}}}
  {\textstyle\vphantom{#1}}}
%scriptstyle
  {\vtop{\ialign{##\crcr
  $\hfil\scriptstyle{#1}\hfil$\crcr\noalign 
  {\nointerlineskip\vskip0.7pt}
  $\scriptstyle\hfil\t\hfil$\crcr}}}
%scriptscriptstyle
  {\vtop{\ialign{##\crcr
  $\hfil\scriptscriptstyle{#1}\hfil$\crcr
  \noalign{\nointerlineskip\vskip0.5pt}
  $\scriptscriptstyle\hfil\t\hfil$\crcr}}}}
\begintt
\def\ut#1{   \def\t{\char'176}
  \mathchoice
%displaystyle  
  {\vtop{\ialign{##\crcr
  $\hfil\displaystyle{#1}\hfil$\crcr\noalign
  {\nointerlineskip\vskip1pt}
  $\hfil\displaystyle\t\hfil$\crcr}}}
%textstyle
  {\smash
  {\vtop{\ialign{##\crcr
  $\hfil\textstyle{#1}\hfil$\crcr\noalign
  {\nointerlineskip\vskip1pt}
  $\hfil\textstyle\t\hfil$\crcr}}}
  {\textstyle\vphantom{#1}}}
%scriptstyle
  {\vtop{\ialign{##\crcr
  $\hfil\scriptstyle{#1}\hfil$\crcr
  \noalign{\nointerlineskip\vskip0.7pt}
  $\scriptstyle\hfil\t\hfil$\crcr}}}
%scriptscriptstyle
  {\vtop{\ialign{##\crcr
  $\hfil\scriptscriptstyle{#1}\hfil$\crcr
  \noalign{\nointerlineskip\vskip0.5pt}
  $\scriptscriptstyle\hfil\t\hfil$\crcr}}}
}
\endtt

Taken together, they allow you to write something
like
$$\ut{A}^{\dddot{a+b}}-\dddot{\ut{c}}_{\dddot{A}}$$
should you ever want. The triple dots don't always look
centred, but this is consistent
with |\dot| and |\ddot|.

Of course, there must be better ways to do both of these,
mustn't there? But a word of warning: I use the cmr fonts.
If you use these definitions for the amr fonts, you will have
to modify them slightly. I originally devloped them with
\TeX tures, which uses cmr, and intended to include them in
the last \TeX line, which was done with micro\TeX, using amr.
 The |\ut| seemed fine, but the |\dddot| looked dreadful!
The moral of this is that you cannot expect that definitions
for one font will necessarily work in another (which you
knew), and that amr and cmr should be treated as different fonts.

I was asked if I could do an `operator that looked
just like the |\diamondsuit| character with a plus sign
in it, the plus filling the symbol', for a book on
logic. At least that isn't too difficult:
\def\diamondplus{\mathop
{\diamondsuit\mkern-14mu
\raise0.45pt\hbox{$+$}}}
\begintt
\def\diamondplus{\mathop
{\diamondsuit\mkern-14mu
\raise0.45pt\hbox{$+$}}}
\endtt
but of course it wasn't big enough. At least
it gives something like $A\diamondplus B$. However I leave
you to fiddle about with all the bits and pieces
that would be required if you used the next |\magstep|
font.

Among all the rather wonderful things in \TeX hax
(well, they make me wonder), were a few macros for
other extended symbols which may be useful
to someone somewhere.
The question from
William LeFebvre at Rice
was ``what am I supposed
to use to represent these different sets:
Real numbers, Natural numbers, Imaginary numbers,
and Complex numbers.'' Leslie Stockhausen and Gus Gassman
of Dalhousie University replied with four short macros.

I confess I have modified
them very slightly, by substituting |\mkern|s
for the use of multiple |\!| and |\;| which I thought non-aesthetic.
I also changed from amssqi to cmssqi, which made
the absolute amounts of movement slightly different ---
but this applied only to |\IC|.

The modified macros then become:
\begintt
\def\IR{\hbox{$I\mkern-6muR$}}
\def\IP{\hbox{$I\mkern-6muP$}}
\def\IN{\hbox{$I\mkern-6muN$}}
\font\sqi=cmssqi8
\def\IC{\hbox{$C\mkern-13.5mu
\raise0.49pt\hbox{\sqi I}\mkern9mu$}}
\endtt
\def\IR{\hbox{$I\mkern-6muR$}}
\def\IP{\hbox{$I\mkern-6muP$}}
\def\IN{\hbox{$I\mkern-6muN$}}
\font\sqi=cmssqi8
\def\IC{\hbox{$C\mkern-13.5mu
\raise0.49pt\hbox{\sqi I}\mkern9mu$}}
Once defined, you can then say things like
$\IC\IR\IP\IN$. The bar of the |\IC| is perhaps
a little close, but the largest `standard' size
of the cmssqi font is 8pt.

\rightline{\sl Malcolm W Clark}
\vfil