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========================================================================
Date:         Tue, 8 Nov 1994 20:35:13 BST
Reply-To: Philip Taylor <P.Taylor@Vax.Rhbnc.Ac.Uk>
From: Philip TAYLOR <CHAA006@VAX.RHBNC.AC.UK>
Subject:      e-TeX: some specific proposals!

Dear Colleagues -- The NTS group have been very quiet of late, and there has
been little discussion of NTS and/or e-TeX on this list.  But although we
have been quiet, we have not been idle, and we now have a definite list of
proposals which we are considering for incorporation in e-TeX.  Please read
the ideas below, and make any comments which you feel appropriate.

                                Philip Taylor,
                                Technical Director, NTS project.
--------

Minutes of the NTS meeting held at Lindau on October 11/12th 1994
=================================================================

Present: Philip Taylor, Jiri Zlatuska, Bernd Raichle, Friedhelm Sowa,
         Peter Breitenlohner, Joachim Lammarsch.

It was AGREED that no progress had apparently been made on the `canonical
TeX kit' project, and that no progress was likely to be made unless and until
an active proponent of the project emerged within, or was recruited to, the
group; accordingly the project was officially placed on ice.

It was AGREED that in the absence of adequate funding for the NTS project
proper, no serious work could be carried out; several possible sources of
funding remained to be explored, and the group were hopeful that this project
would see the light of day before too long.  [ACTION: JZ, JL]

It was AGREED that the e-TeX project was both feasible and very worthwhile, and
that all efforts should initially be concentrated on achiving progress in this
area.  With the benefit of hindsight it was AGREED that the original proposal
to issue new releases at six-monthly intervals had been over-optimistic, and
that a more realistic timescale would involve new releases once per year.  It
was also AGREED that the first release should be accomplished as soon as
possible, consistent with the need to ensure that the code released was both
bug-free and unlikely to require more than a minimum of re-thinking in the
light of experience.

The group attempted to identify as many ideas as possible which either has
already been proposed for incorporation in e-TeX, or which were natural
consequences of (or alternatives to) ideas already proposed.  The remainder
of this document lists the various ideas mooted, and discusses their intention
and implementation.

--------

\horigin, \vorigin (dimen registers, default = 1 in).
These two registers, requested by Phil, will serve to make explicit for the
first time the canonical (1", 1") origin decreed by DEK in the definition of
the DVI format, and on which all formats are currently predicated.  Phil
explained that his college, amongst others, had eschewed this convention right
from the outset, and has instead adopted the more logical (0", 0") origin,
requiring all drivers to be configured in a non-standard manner.  Providing
the origin registers within e-TeX would allow all drivers to be reconfigured
to the standard, whilst existing practices could be maintained simply by local
initialisation of the registers to (0", 0").  As e-TeX might eventually require
the adoption of a new version of the DVI format (to encompass, for example,
colour), that might also be the appropriate time at which to propose universal
adoption of a (0", 0") origin.

\<enhancement>state (internal integer registers, one for each enhancement).
A unified mechanism is proposed for all enhancements [1] whereby an internal
integer register is associated with each, the name of the register being derived
from the concatentation of the name of the enhancement and the word `state';
such registers are read/write, and if their value is zero or negative the
associated enhancement is disabled [2].  If a positive non-zero value is
assigned to anu such register, then the associated enhancement shall be
enabled, and if the register is interrogated then a positive non-zero value
shall indicate that the associated enhancement is enabled.  It is possible
that in a future release differing values assigned to or returned by such
registers may indicate the revision-level of enhancements, and therefore it
is initially recommended that only the values zero or one be used.

\TeXXeTstate, \MLTeXstate (internal integer registers).
These are the only two enhancements currently under consideration, although
Bernd Raichle also has a proposal for an alternative ligaturing mechanism
which would probably of necessity form an enhancement if adopted.  MLTeX
is not proposed for incorporation in the first release, but may be incorporated
in the second.  The group acknowledges the generosity of Michael Ferguson in
allowing the incorporation of his work on MLTeX.

\interactionmode (internal integer register).
Allows read/write access to the present \scrollmode, \nonstopmode, etc.,
family of primitives; the values will be a monotic sequence of period one,
and descriptive names will be associated through the e-plain (and e-LaTeX?)
formats. [3]

<additional \tracing... detail>
Peter has implemented augmented semantics for some of the \tracing commands
whereby increasingly positive values given increasingly detailed output.

\protected (new prefix for macro definitions).
Analogous to \long, \outer, etc., causes the associated macro to be
non-expanding in contexts where such behaviour is likely to be undesirable
(in particular in \writes and \edefs); an explicit \expandafter \empty
may be used to force expansion in these circumstances.

\bind (new prefix for macro definitions).
Proposed by Phil, this was intended to allow macros to be bound to the
current _meaning_ of embedded control sequences rather than to their names,
in a manner analogous to PostScript's `bind def'.  However the group were
unconvinced of the merits of this proposal, and it was classified as
`more work needed' (MWN).

\evaluate {<arithmetic expression>}.
Intended for use on the r-h-s of \count, \dimen and \skip assignments,
it would allow the use of infix arithmetic operators such as +, -, * and /;
the type of the result would, in general, be the type of the simplest operand
forming a part of the expression, and the normal semantics of TeX would allow
this to be further coerced where necessary.  Parenthesised sub-expressions
would be allowed.  [4]

\contents <box #>.
Proposed by Jiri, this is intended to allow the TeX programmer access to the
sort of information normally only available via the log file as a result of
a \show; in principle it would generate the simplest list of TeX tokens which
would generate the box specified, assuming that each token generated still
had its canonical meaning.  MWN.

<anchors>: Proposed by Jiri, an ``anchor point'' would be in some senses
be analogous to a mark, but rather than recording textual information it
would instead record the co-ordinates of itself, relative to the reference
point of the smallest surrounding box.  Additional new primitives would
be required to return the co-ordinates of a specified anchor point. MWN.

\scantokens {<balanced text>}.
Allows an existing token-list to be re-input under a different catcode regime
from that under which it was created; as it uses all of TeX's present \input
mechanism, even %%ff notation will be interpreted as if \input.  Causes an
`empty filename' to be input, resulting in `( )' appearing in the log file
if \tracingscantokens (q.v.) is strictly greater than zero.  If the token list
represents more than one line of input, and if an error occurs, then
\inputlinenumber will reflect the logical input line from the token list rather
than the current input line number from the current file.

\unexpanded {<balanced text>}.
An alternative to \protected, for use when a whole brace-delimited token
list (`balanced text') is to be protected from expansion.  Intended to be
use in \writes and \edefs.

\every<whatever>.
The group discussed many possibilities of implementing additional \every
primitives in e-TeX; most were classified as MWN, but one (\everyeof) is
being considered for e-TeX version 1.

\futuredef <cs> <tok> <tok>.
Analogous to \futurelet, but the <cs> will be expandable, and expand to the
next token encountered (or to the next balanced text if the next token is
of catcode 1).  MWN.

\futurechardef <cs> <tok> <char-or-tok>.
A combination of \futurelet and \chardef, will allow the next character to
be inspected and its character code returned iff it has not yet been tokenised.
If tokenisation has already taken place, will return -1.  Intended to allow
the catcode of the next character to be changed based on its value.

\ifdefined <cs>.
Allows direct testing of whether or not a given <cs> is defined.

\ifcsname ... \endcsname.
Ditto, but for a sequence of <tokens-expanding-to-characters>; this also
avoids wasting of hash table space.

\unless <boolean-if>.
Inverts the sense of the following boolean-if; particularly useful in
conjunction with \ifeof in \loop ... \ifeof ... \repeat constructs,
but also of use with (say) \ifdefined and \ifcsname.

\TeX<whatever>state.
More work needed!  A mechanism whereby a TeX document can ask TeX some
questions about the current state of its digestive tract.  For example it
would be nice to know if TeX was currently involved in an assignment, and
if so which part of the assignment was currently being elaborated.

\marks <integer>
Allows, for the first time, a whole family of marks rather than just the one
provided by TeX; will also require analogous \topmarks <integer>, etc.  The
group propose to provide 16 such marks, but are interested to know if the
(La)TeX community consider this sufficient.   A related \markdef primitive
may be provided to simplify mark allocation, in a manner analogous to the
existing \...def primitives.

\deferred \special (or perhaps \deferredspecial).
At the moment, only \writes are deferred; there are cases when it would
be desirable for other things, too, to be expanded only during \shipout,
and \specials are one of these.

\textcode <integer>.
Could provide a text-mode analogy to TeX's \mathcode.  MWN.

\middle <delimiter>.
Analogous to \left and \right, allows delimiters to be classed as \middle,
and their spacing thereby adjusted.

\filename.
Would allow access to the name of the file currently being \input.
Lots of discussion on just how much or how little should be returned.
MWN.

\OSname.
Very contentious.  Would provide the name of the operating system, and
thereby allow documents to behave differently on different systems.
Deprecated on that basis, and will not be provided unless/until a \system
primitive is also provided.

\system {<balanced text>}.
Definitely not proposed for e-TeX version 1.  Would allow operating system
calls to be made, and their status and result(s) returned in some way.
A lot MWN.

\tracingscantokens (internal integer register).
See \scantokens.

<smarter discretionaries, e.g. \discretionarylefthyphenmin>.
Hyphenation after an implicit hyphen is sometimes highly desirable, and
the group are investigating mechanisms whereby this could be both provided
and parameterised.  MWN.

\everyhyphen (token list register).
Would allow TeX's present hard-wired behaviour of placing an empty
discretionary after every explicit hyphen to be modified.  However, there
are potentially problems of recursion, and perhaps even a need to remove
the hyphen.  MWN.

\clubpenalties, \widowpenalties.
A start at improving TeX's penalty system by making it more flexible.  These
two penalty `arrays' would allow a different penalty to be associated with
one-line widows, two-line-widows, etc.  [5]

\ifenhanced.
A boolean-if which would return -true- iff any enhancement is enabled.
Would allow a e-TeX document to check if it is being processed in `extended'
more or `enhanced' mode.  Phil argues for this one but the group are
unconvinced: the advice of the TeX community is to be sought.

\lastnodetype.
Would allow, for the first time, the unambiguous identification of the type
of the last node of one of TeX's internal lists, removing (for example) the
ambiguity when \lastpenalty returns 0 (which can indicate no penalty node,
or a penalty node with value 0).  Would return one of a monotonic series of
integers of period one.  Meaningful names would be assigned to these through
the e- series formats [3].

\unnode.
Would allow the removal of _any_ node from the end of one of TeX's internal
lists.

\lastnode.
Perhaps analogous to \contents (q.v.), or perhaps quite different, would allow
access to the value of the last node of one of TeX's internal lists.
Generalises TeX's present mechanism whereby only a subset of nodes can be
accessed.  MWN.

\readline <integer> to <cs>.
Allows a single line to be read from an input file as if each character
therein had catcode 12 [6].  Intended to be used for verbatim copying
operations, in conjunction with \scantokens, or to allow error-free parsing
of `foreign' (non-TeX) files.

\everyeof {<balanced text>}
Provides a hook whereby the contents of a token list register may be
inserted into TeX's reading orifice when end-of-file is encountered
during file reading.  Would not be invoked of the file indicated
logical e-o-f through the medium of \endinput.  Proposed by Phil
to allow clean processing of file-handling code which requires
a (sequence of characters yielding) \else or fi to be found in a
file, where no such sequence can be guaranteed.

\listing (internal integer register).
Would allow the generation of a listing containing (for example) TeX's analysis
of current brace depth, macro nesting, etc. Different positive values would
allow different amounts of information to be generated.  Would the TeX
community like such a feature?

\defaultextension.
Would allow TeX' present hard-wired behaviour of appending .TeX to a filename
not possessing an explicit extension to be modified, allowing an alternative
extension to be specified.  Would this be of use to the L2e/L3 team, and/or
to the TEX world in general?

<fixed point arithmetic>.
Several of the above ideas cannot be implemented at the moment, as they
would allow access to the `forbidden area' of machine-dependent arithmetic.
If TeX's present floating point calculations were replaced by Knuth's
fixed-poing arithmetic proposals, then there would no longer be a forbidden
area and all such ideas could, in principle, be implemented.

Notes:

[1] `Extensions' are basically new primitives which have no effect on the
     semantics of existing TeX documents, except insofaras any document which
     tests whether such a primitive is, in fact, undefined, will clearly obtain
     opposite results under TeX and e-TeX; `enhancements' are more fundamental
     changes to the TeX kernel which may affect the semantics of existing TeX
     documents even if no new primitive is used or even tested.  Such changes
     may be, for example, differences in the construction of TeX's internal
     lists, or perhaps different hyphenation or ligaturing behaviour.

[2]  It is currently proposed that all enhancements be disabled by e-IniTeX
     immediately prior to the execution of \dump.  This decision was taken
     based on the advice of Frank Mittelbach.

[3]  Question: should there, in fact, be an e-plain (or e-LaTeX) format,
     or should there simply be an e-plain.tex file which can be loaded by
     a user document?  Peter votes for an e-plain.tex file that will \input
     plain.tex but no hyphenation patterns.

[4]  Should e-TeX allow access to more powerful operators than just
     +, -, * and /?

[5] `Arrays' are not very obvious in TeX at the moment, although there are,
     for example, \fontdimens and such-like.  But should these have fixed
     bounds (as in 256 count registers, for example), or arbitrary upper
     bounds (as in font dimens, if the `extra' elements are assigned as
     soon as the font is loaded).  Or should they be finite-but-unbounded,
     as in \parshape, wherein the first element indicates the number of
     elements which follow?  These questions are applicable to marks as
     well as to penalties...

[6]  Should spaces have catcode 10 for this operation?  Peter thinks so,
     but based on existing simulations of this operation, I [PT] am more
     inclined to think they should have catcode 13.

========================================================================
Date:         Tue, 8 Nov 1994 22:20:56 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "Denis B. Roegel" <Denis.Roegel@LORIA.FR>
Subject:      suggestion for NTS

I just read the minutes of the October meeting and find
it very interesting. If I were millionaire, I would
immediately help e-TeX, but alas...

Anyway, a few days ago, I noticed something which is quite
difficult to do in TeX and which might be improved. It is the
fact that when a paragraph is cut in lines and these lines
are added to previous accumulated pages in order to form
a page, several lines are left back for the next pages.
These lines are set in boxes and unfortunately some
informations are lost. Sometimes, you wish to unset these
set lines and since information is lost, it would be
interesting to have these lines as tokens in a special
token list. The problem I think is to find a correspondance
between where the page ends between the lines, and where
the page ends in this token list. I feel there are cases
where this is simple.

So, if this were possible, you could easily add a command
in the output routine which would unset the lines already set,
insert a \parshape and cut some shape out of each page.
Wouldn't that be neat ?

Well just a suggestion...and if not for e-TeX, please consider
it for NTS.

Regards,

Denis.

========================================================================
Date:         Tue, 8 Nov 1994 17:15:00 -0500
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: bbeeton <BNB@MATH.AMS.ORG>
Subject:      Re: e-TeX: some specific proposals!
In-Reply-To:  <01HJ8PR36T2QEBODFE@MATH.AMS.ORG>

having just undergone some rather painful experiences with poorly
checked input, i'd really like to be able to inquire about the
current nesting level.  this perhaps falls in the category of
"\listing", about which feedback was requested.  i'm not sure i
want a great deal of detail though -- just a register whose value
i could test from time to time to make sure that things haven't
gotten out of hand.  this would make it possible, for instance,
to trigger an error message reasonably near the source of a
problem rather than waiting for the end of a job.
                                                -- bb

========================================================================
Date:         Wed, 9 Nov 1994 10:10:17 +0100
Reply-To: flexus!RfSchtkt@maze.ruca.ua.ac.be
From: Raf Schietekat <flexus!rfschtkt@MAZE.RUCA.UA.AC.BE>
Subject:      TeX grammar

LS,

Can TeX be parsed by something like lex/yacc, and if so, where can I find the
sources, if available for free? Maybe only subsets of TeX can be handled this
way? Or maybe it's hopeless altogether? I've tried to compile (traditional
meaning) a grammar from the information in `The TeXbook', but I've encountered
all sorts of problems when trying to compile it (computer science meaning).

Thanks,

Raf Schietekat, RfSchtkt@maze.ruca.ua.ac.be, Flanders, Belgium
(real, i.e., with triangle in the Deliver button) NeXTmail preferred
Addressing limitations: no !, % or .uucp, I think

PS: Please reply to my address, because my system/situation throws away all
messages from this list (I have to lie in ambush to pick incoming messages out
of the uucp queue). If you're a uucp guru...

========================================================================
Date:         Wed, 9 Nov 1994 18:44:38 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: Joachim Schrod <schrod@ITI.INFORMATIK.TH-DARMSTADT.DE>
Subject:      Re: TeX grammar
In-Reply-To:  <199411091736.SAA19623@rs3.hrz.th-darmstadt.de> from "Raf
              Schietekat" at Nov 9, 94 10:10:17 am

Raf Schietekat wrote:
>
> Can TeX be parsed by something like lex/yacc

No. As a macro language TeX has an extensible grammar. That cannot be
modelled with parser generators like the one above. One has to use
modifiable grammars.

What makes such tools even more unsuitable, is the point that the
lexical analysis can be configured.

It's not a problem per se to parse TeX; Common Lisp's macro language
and its configurability is by far more complex (and more powerful)
than TeX; it simply isn't your classic Aho-Hopcraft-Ullman-textbook
type of language.

        Joachim

--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Joachim Schrod                  Email: schrod@iti.informatik.th-darmstadt.de
Computer Science Department
Technical University of Darmstadt, Germany

========================================================================
Date:         Wed, 9 Nov 1994 18:57:38 BST
Reply-To: Philip Taylor <P.Taylor@Vax.Rhbnc.Ac.Uk>
From: Philip TAYLOR <CHAA006@VAX.RHBNC.AC.UK>
Subject:      Re: suggestion for NTS

Denis --

>> I just read the minutes of the October meeting and find
>> it very interesting. If I were millionaire, I would
>> immediately help e-TeX, but alas...

We shall all pray for you to win a lottery!

>> Anyway, a few days ago, I noticed something which is quite
>> difficult to do in TeX and which might be improved. It is the
>> fact that when a paragraph is cut in lines and these lines
>> are added to previous accumulated pages in order to form
>> a page, several lines are left back for the next pages.
>> These lines are set in boxes and unfortunately some
>> informations are lost. Sometimes, you wish to unset these
>> set lines and since information is lost, it would be
>> interesting to have these lines as tokens in a special
>> token list. The problem I think is to find a correspondance
>> between where the page ends between the lines, and where
>> the page ends in this token list. I feel there are cases
>> where this is simple.

This is a very interesting proposal, and one which I believe
Frank Mittlebach has already proved possible: thank you very
much for reminding us of it -- I will add it to the list of
ideas which must be considered.

                                ** Phil.

========================================================================
Date:         Thu, 10 Nov 1994 19:45:00 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: Jonathan Fine <J.Fine@PMMS.CAM.AC.UK>
Subject:      Turning a set paragraph into tokens

Dear NTS Reader
In a recent posting Denis Roegel asks for a command which would
>       unset lines already set
so that the output routine could
>       cut some shape out of each page.

The purpose for which Roegel requests the new command can be
accomplished with TeX as it is, by writing some admittedly tricky
macros.  For example, see articles by Alan Hoenig in TUGBoat.

best regards
Jonathan Fine

========================================================================
Date:         Thu, 10 Nov 1994 22:02:28 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: Joachim Schrod <schrod@ITI.INFORMATIK.TH-DARMSTADT.DE>
Subject:      Re: Turning a set paragraph into tokens
In-Reply-To:  <199411101948.UAA35319@rs3.hrz.th-darmstadt.de> from "Jonathan
              Fine" at Nov 10, 94 07:45:00 pm

On another point concerning that subject: It was announced that e-TeX
shall really be able to `rescan' a token list, to be able to process
an input with different catcodes.

I would like to know how the rescan of \tok, as defined in

    \let\u=\uppercase               % contains `s'

    \newtoks\tok

    \catcode`\s=10
    \tok\expandafter{\u{asb}}
    \catcode`\s=11

is handled. To make my point clear, for those who do not know TeX by
heart: The `s' is lost and cannot be recovered in TeX.

        Joachim

--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Joachim Schrod                  Email: schrod@iti.informatik.th-darmstadt.de
Computer Science Department
Technical University of Darmstadt, Germany

========================================================================
Date:         Thu, 10 Nov 1994 23:00:52 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      \oddhoffset, \evenhoffset, etc.

\oddhoffset, \evenhoffset, \oddvoffset, \evenvoffset

If you have a printer capable of real twosideprinting, it may happen, that
the front page and the back page have different offsets and you want to
correct for it separately. I remember that this problem was once mentioned
on de.comp.tex.

--J"org Knappen.

========================================================================
Date:         Thu, 10 Nov 1994 23:02:23 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      \horigin

\horigin, \vorigin

I don't see the gain of these two commands. In fact, there is no
``natural'' origin of the coordinate system at all. The upper left corner
looks very unnatural as well, why shouldn't it be the lower left corner
with the usual orintation of axes? However, shifting around the coordinate
system does not give you anything you don't have in the old one, therefore
the standard is better left untouched.

--J"org Knappen.

========================================================================
Date:         Thu, 10 Nov 1994 15:51:28 -0500
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: Michael Downes <MJD@MATH.AMS.ORG>
Subject:      Re: Turning a set paragraph into tokens
In-Reply-To:  <01HJBGMLEC6QEBOQQC@MATH.AMS.ORG>

(Denis Roegel:)
> fact that when a paragraph is cut in lines and these lines
> are added to previous accumulated pages in order to form
> a page, several lines are left back for the next pages.
> These lines are set in boxes and unfortunately some
> informations are lost. Sometimes, you wish to unset these
> set lines and since information is lost, it would be
> interesting to have these lines as tokens in a special
> token list. The problem I think is to find a correspondance
> between where the page ends between the lines, and where
> the page ends in this token list. I feel there are cases
> where this is simple.

(Jonathan Fine:)
> The purpose for which Roegel requests the new command can be
> accomplished with TeX as it is, by writing some admittedly tricky
> macros.  For example, see articles by Alan Hoenig in TUGBoat.

Yes, and I don't think it would be wise to attempt to keep track of a
correspondence between tokens and the lines of a paragraph; that would
be an attempt to find synchronization between two very different, very
*asynchronous* data types (token stream versus horizontal list). The
most natural thing to do, within the current framework of TeX, would be
to save the trailing part of the paragraph in a box register as a single
unbroken line and make that accessible in the output routine. And even
then I think you have difficult complications because linebreaking and
the movement of material from `recent contributions' to `current page'
are separate steps. Consider also that the desired behavior cuts
unnaturally across TeX's optimization of line breaks over an entire
paragraph: the line breaks that TeX finds if the tail of the paragraph
is left as a single unbroken line might differ from the line breaks that
TeX finds if the tail of the paragraph is fully broken. This in turn can
affect the height/depth of the lines that fall at the page boundary,
which would seem to imply a fundamental instability in the decision
about where the tail of the paragraph is to be broken off!

Michael Downes
mjd@math.ams.org

========================================================================
Date:         Thu, 10 Nov 1994 23:01:33 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      \evaluate

\evaluate

I think, that the following three functions are a must: sin, cos, sqrt.
Pythagorean addition (like METAFONT's `++') is also worth considering.

The other arithmetic features of METAFONT are also fine, but I don't want
to go over the top (OTT). It would be difficult enough to implement
\evaluate anyhow.

--J"org Knappen.

========================================================================
Date:         Thu, 10 Nov 1994 23:06:58 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      \fancyprompt

\fancyprompt

allow configuration of the TeX prompt (default `*').

*\fancyprompt{eTeX>}
eTeX>

--J"org Knappen.

========================================================================
Date:         Thu, 10 Nov 1994 23:03:54 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      Make eTeX less batch orientated

The following is something new and rather different from the current
proposals. The idae behind is having TeX ready in the memory and avoid
loading it anew for each run again and again which costs lots of startup
time, if you have to load everything via NFSS.

The idea I am toying with is to have something like
     \level
which clones the current state of TeX and allows to start a new dvi-file.
Then you do what you want (start even another \level, if you want, and at
last you say
     \exit
which performes like \end, except that it restores exactly the state before
the last cloning.

Wait a minute, you want to may communicate some information to the waiting
lion. So there may be one exeption. You say
     \exit{some_integer_number}
and this number can be read by using
     \exitstatus.

Applications are many. If you have a format which usually requires several runs,
 you
can do all the runs within one job, and automatically decide, wether a
further run is necessary. Of course, you should device your format to have
a counter maxruns to avoid endless looping...

--J"org Knappen.

========================================================================
Date:         Thu, 10 Nov 1994 22:46:01 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "Denis B. Roegel" <Denis.Roegel@LORIA.FR>
Subject:      Re: Turning a set paragraph into tokens
In-Reply-To:  <199411101947.UAA29243@lorraine.loria.fr> from "Jonathan Fine" at
              Nov 10, 94 07:45:00 pm

'Jonathan Fine'
>
>   Dear NTS Reader
>   In a recent posting Denis Roegel asks for a command which would
>   >       unset lines already set
>   so that the output routine could
>   >       cut some shape out of each page.
>
>   The purpose for which Roegel requests the new command can be
>   accomplished with TeX as it is, by writing some admittedly tricky
>   macros.  For example, see articles by Alan Hoenig in TUGBoat.
>

I don't doubt this is possible in TeX, since everything is possible
within TeX. But it is difficult. And also unefficient.
Here is an excerpt of an exchange with Donald Arseneau:

DA> ... I must say that you can't unbox paragraphs and
DA> re-set them: choice of discretionary (hyphenation) and discarding are
DA> permanent; they cannot be restored.  To have a chance at reshaping a
DA> paragraph, you must keep either the original text of the paragraph, or
DA> set it on a single line (\hsize=\maxdimen) and keep that box.  See
DA> shapepar.sty. It would be much better to use non-TeX.

I had understood that one purpose of e-TeX was to ease things
that were otherwise difficult, or am I wrong ?

Denis.

========================================================================
Date:         Fri, 11 Nov 1994 11:29:11 BST
Reply-To: Philip Taylor <P.Taylor@Vax.Rhbnc.Ac.Uk>
From: Philip TAYLOR <CHAA006@VAX.RHBNC.AC.UK>
Subject:      Quick response to recent proposals

My thanks to those who responded to the recent list of proposals for e-TeX:
here are my immediate reactions to the new suggestions; other members of the
team will probably want to respond individually:

                                        **  Phil.
--------
>> On another point concerning that subject: It was announced that e-TeX
>> shall really be able to `rescan' a token list, to be able to process
>> an input with different catcodes.

>> I would like to know how the rescan of \tok, as defined in

>>     \let\u=\uppercase               % contains `s'

>>     \newtoks\tok

>>     \catcode`\s=10
>>     \tok\expandafter{\u{asb}}
>>     \catcode`\s=11

>> is handled. To make my point clear, for those who do not know TeX by
>> heart: The `s' is lost and cannot be recovered in TeX.

If e-TeX sees \scantokens {\tok}, it will simply process the
characters "\tok" under the current catcode regime; if it
sees \scantokens \expandafter {\tok}, then I would expect it
to scan "\u{a b}", but Peter (who proposed and implemented this
feature) is better placed than I to explain exactly what he intends
it to do.  I'm sure he will respond shortly.
--------
>> \oddhoffset, \evenhoffset, \oddvoffset, \evenvoffset

>> If you have a printer capable of real twosideprinting, it may happen, that
>> the front page and the back page have different offsets and you want to
>> correct for it separately. I remember that this problem was once mentioned
>> on de.comp.tex.

I really cannot see a genuine need for this: \hoffset & \voffset are
honoured _only_ during shipout; it is a very simple matter for the
output routine to tweak them just prior to threading \shipout.
Or have I missed something?
--------
>> \evaluate

>> I think, that the following three functions are a must: sin, cos, sqrt.
>> Pythagorean addition (like METAFONT's `++') is also worth considering.

If we allow trig functions we must implement them using integer arithemetic,
otherwise portability issues will become a problem.  It is _very_ hard
to know where to stop once you go beyond the basic four (plus, perhaps,
mod and div).  But ++ is a nice idea.

>> The other arithmetic features of METAFONT are also fine, but I don't want
>> to go over the top (OTT). It would be difficult enough to implement
>> \evaluate anyhow.
--------
>> \horigin, \vorigin

>> I don't see the gain of these two commands. In fact, there is no
>> ``natural'' origin of the coordinate system at all. The upper left corner
>> looks very unnatural as well, why shouldn't it be the lower left corner
>> with the usual orintation of axes? However, shifting around the coordinate
>> system does not give you anything you don't have in the old one, therefore
>> the standard is better left untouched.

There are several reasons for eschewing the (1", 1") convention.

(1) It's irrational: what on earth is special about 1" down, 1" in?
(2) It's nonsensical if you trying to set 35mm slides at natural size;
(3) Today's undergradutes don't know what an inch is...
(4) For pedagogical reasons, I always teach that \horigin reprsents
    the left margin, and \vorigin represents the top margin: I'd hate
    to have to qualify this by ``provided that you first subtract one inch''.
--------
>> The following is something new and rather different from the current
>> proposals. The idae behind is having TeX ready in the memory and avoid
>> loading it anew for each run again and again which costs lots of startup
>> time, if you have to load everything via NFSS.

>> The idea I am toying with is to have something like
>>      \level
>> which clones the current state of TeX and allows to start a new dvi-file.
>> Then you do what you want (start even another \level, if you want, and at
>> last you say
>>      \exit
>> which performes like \end, except that it restores exactly the state before
>> the last cloning.

>> Wait a minute, you want to may communicate some information to the waiting
>> lion. So there may be one exeption. You say
>>      \exit{some_integer_number}
>> and this number can be read by using
>>      \exitstatus.

>> Applications are many. If you have a format which usually requires several
 runs,
>>  you
>> can do all the runs within one job, and automatically decide, wether a
>> further run is necessary. Of course, you should device your format to have
>> a counter maxruns to avoid endless looping...

Very interesting: there are other calls for allowing more than one DVI file;
certainly worthy of further consideration.
--------
>> \fancyprompt

>> allow configuration of the TeX prompt (default `*').

>> *\fancyprompt{eTeX>}
>> eTeX>

Seems pretty cosmetic to me: is this a serious proposal?
--------
>> Yes, and I don't think it would be wise to attempt to keep track of a
>> correspondence between tokens and the lines of a paragraph; that would
>> be an attempt to find synchronization between two very different, very
>> *asynchronous* data types (token stream versus horizontal list). The
>> most natural thing to do, within the current framework of TeX, would be
>> to save the trailing part of the paragraph in a box register as a single
>> unbroken line and make that accessible in the output routine. And even
>> then I think you have difficult complications because linebreaking and
>> the movement of material from `recent contributions' to `current page'
>> are separate steps. Consider also that the desired behavior cuts
>> unnaturally across TeX's optimization of line breaks over an entire
>> paragraph: the line breaks that TeX finds if the tail of the paragraph
>> is left as a single unbroken line might differ from the line breaks that
>> TeX finds if the tail of the paragraph is fully broken. This in turn can
>> affect the height/depth of the lines that fall at the page boundary,
>> which would seem to imply a fundamental instability in the decision
>> about where the tail of the paragraph is to be broken off!

But Frank has shewn that it _can_ _be_ _done_.  The output routine is
an irrelevancy in this: what is needed is \reconsiderparagraphs, which
allows all material carried over from the current paragraph at a page
break to be re-subjected to (e-)TeX's paragraphing algorithm.

>> I don't doubt this is possible in TeX, since everything is possible
>> within TeX. But it is difficult. And also unefficient.
>> Here is an excerpt of an exchange with Donald Arseneau:

>> DA> ... I must say that you can't unbox paragraphs and
>> DA> re-set them: choice of discretionary (hyphenation) and discarding are
>> DA> permanent; they cannot be restored.  To have a chance at reshaping a
>> DA> paragraph, you must keep either the original text of the paragraph, or
>> DA> set it on a single line (\hsize=\maxdimen) and keep that box.  See
>> DA> shapepar.sty. It would be much better to use non-TeX.

>> I had understood that one purpose of e-TeX was to ease things
>> that were otherwise difficult, or am I wrong ?

No, that's _exactly_ the point.  As I said in my earlier reply, this
is a very important proposal which I am extremely glad you reminded
us about.

                                        ** Phil.

========================================================================
Date:         Fri, 11 Nov 1994 11:48:00 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: Jonathan Fine <J.Fine@PMMS.CAM.AC.UK>
Subject:      Re: Turning a set paragraph into tokens

Denis Roegel wrote
>    I had understood that one purpose of e-TeX was to ease things
>    that were otherwise difficult
and he may be right.

Knuth provided macros so that things could be done without writing
a whole new program.  To my mind it is very important to know of any
required facility, whether it is
a)  possible and not hard
b)  possible and hard
c)  not possible
by writing macros or by improving the .dvi driver.

For example, the \vorigin, \horigin feature can be provided by writing macros.
(It's a question of intercepting the \shipout command, and this can be done
by using the \afterbox macros that Sonja Maus published in TUGboat a while ago.)

Now for the facility Roegel requested.  This is, he agrees, possible but hard.
I'm in favour of making things easier, but for the life of me, I cannot see how
turning s set box into tokens will help.

I am in broad agreement with the contribution of Michael Downes on this matter.

with best regards
Jonathan Fine

========================================================================
Date:         Mon, 14 Nov 1994 15:05:01 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: David Carlisle <carlisle@CS.MAN.AC.UK>
Subject:      Re: e-TeX: some specific proposals!
In-Reply-To:  <9411082043.AA13490@m1.cs.man.ac.uk> (message from Philip TAYLOR
              on Tue, 8 Nov 1994 20:35:13 BST)

The following is a (very slightly) modified version of some comments I
sent to Phil after he spoke about these proposals at UKTUG. I have
modified the comments slightly in the light of other comments made
since then on this list

David
=============================================================
General point first:

Some of these new primitives take up some nice names
that users may want to use (or have used) in documents, I realise that
the commands only become activated if the extensions are enabled, but
these names may cause problems in converting documents to use etex
features, and mean that it becomes hard to use those command names in
future.

As almost all the extra commands are aimed at the macro programmer
rather than the document author, had your group ever considered giving
the commands more `internal' names, eg with a unique prefix

\etexevaluate
\etexfilename

etc

I suggest etex as the prefix here as it is all letters, actually I
would go further and use @ or _ in the names, macro files easily
arrange to have the right catcode, and this leaves the `letters' name
space free for user commands.
\future_def ?



> \horigin, \vorigin & <dimen registers>, default = 1 in & logical page origin

Not sure that this gives you anything (and takes up a nice name)

\horigin=???
appears to be
\hoffset=-1in \advance\hoffset by ???


Others have commented on this too. It seems that the desired semantics
can easily be gained without this extension.



> \interactionmode & <count register> & read/write access to \scrollmode, etc.

Also versions of \scrollmode and friends that obeyed TeX's normal scoping
rules would be useful.

> \protected <macro definition> & <primitive> & prefix analogous to
>   \long, \outer, ...

Need to think whether your suggested semantics (never expand in edef-y
things) is enough, or whether one really would need some kind of
\protectionlevel
parameter
(0= normal usage, 1= protected macros dont expand)
or something.

> \evaluate {<arithmetic expression>} & <skip primitive> & evaluates
> and returns arithmetic expression

Would this add to the list of characters that have special
significance in the etex bnf expression descriptions. eg ( * / )
as well as + - .   ??


> \ifdefined <cs> & <if-primitive> & tests if <cs> is defined without
> wasting hash-table space

I thought that \ifx\foo\undefined did not waste hash space either ?

> \ifcsname ... \endcsname & <if-primitive> & tests if constructed
> <cs> is defined without wasting hash-table space

I think this is atacking the wrong problem.
It is not the
\expandafter\ifx\csname foo \endcsname\undefined
construct that is broken. It is the \csname primitive.

What is desparately needed is a primitive like csname, but generates
the standard TeX undefined command error if \foo is undefined.

Then

\expandafter\ifx\csnamedoneright foo \endcsnamedoneright\undefined

ought to work as well as

\ifx\foo\undefined

but more importantly could stop doing the current mess of having to
check whether foo is defined, and raise an error `by hand' if not,
before executing \csname foo \endcsname

> \markdef <cs> <integer> & <mark allocater> & allows multiple (16) marks

Fixed, especially fixed low, upper limits are a bad thing in general,
and in particular here. 16 will not be enough.

ideally just
\marktoken <cs>  to allow an arbitrary number of marks. If that is not
in the TeX style please let <cs> be an arbitrary <count> value.

Presumably this comes with matching typed versions of \mark \firstmark
etc to actually use the typed marks?


> \filename & <primitive> & analogous to \jobname
As I mentioned, I would like all these commands to get internal names,
but \filename would be a particularly nice name for users to lose.


> \defaultextension & <?string register?> & specifies alternative to `.tex'

Doesn't buy you much within the document, where the macro level can do
this quite easily. (LaTeX does a lot of this sort of thing) however
being able to change the default extension on the command line
implicit input would be useful.

Actually this made me think, it would be useful to be able to
change that default  behaviour of adding \input, if some suitable syntax
could be found, perhaps a token register, defaulting to {\input}.

Currently for any files input with \input{foo} LaTeX avoids TeX's
unfriendly missing file error, with its own error loop. It can not do
this with files on the command line as it can not grab the filename
very easily/

> <fixed point arithmetic>

Yes please, then give me \last-everything \un-everything :-)




========

One other feature would be nice. This is not a change to the language
of TeX itself, but rather to its `standard implementation'.

Currently

\global\let\foo\undefined

makes \foo act in all (I think?) respects as if \foo had never been
defined, however \foo still sits in the hash table taking up a
valuable slot that can never be used for any other command. Would it
be possible for this to be de-allocated?

David

========================================================================
Date:         Mon, 14 Nov 1994 11:02:41 -0500
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: bbeeton <BNB@MATH.AMS.ORG>
Subject:      Re: e-TeX: some specific proposals!
In-Reply-To:  <01HJGS6A3I76EBOZKF@MATH.AMS.ORG>

among other requests for e-tex, david carlisle has proposed the
following:

    One other feature would be nice. This is not a change to the language
    of TeX itself, but rather to its `standard implementation'.

    Currently

    \global\let\foo\undefined

    makes \foo act in all (I think?) respects as if \foo had never been
    defined, however \foo still sits in the hash table taking up a
    valuable slot that can never be used for any other command. Would it
    be possible for this to be de-allocated?

when knuth was asked about this, a long time ago, his response was
that he was unable to tell whether in fact a \cs was defined elesewhere,
locally, and to continually be defining and undefining the same thing
would be wasteful and time-consuming.  i think there was also some
consideration of clearing things out of the middle of the hash table
(the same reason given for not being able to remove a file name from
the string pool unless it is the very last thing put onto the list).
i will try to look up the reference if that is considered useful.
also, peter may have a different opinion ...
                                                -- bb

========================================================================
Date:         Mon, 14 Nov 1994 17:13:01 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "Denis B. Roegel" <Denis.Roegel@LORIA.FR>
Subject:      Re: e-TeX: some specific proposals!
In-Reply-To:  <199411141606.RAA15561@lorraine.loria.fr> from "bbeeton" at Nov
              14, 94 11:02:41 am

'bbeeton'
>
>   among other requests for e-tex, david carlisle has proposed the
>   following:
>
>       One other feature would be nice. This is not a change to the language
>       of TeX itself, but rather to its `standard implementation'.
>
>       Currently
>
>       \global\let\foo\undefined
>
>       makes \foo act in all (I think?) respects as if \foo had never been
>       defined, however \foo still sits in the hash table taking up a
>       valuable slot that can never be used for any other command. Would it
>       be possible for this to be de-allocated?
>
>   when knuth was asked about this, a long time ago, his response was
>   that he was unable to tell whether in fact a \cs was defined elesewhere,
>   locally, and to continually be defining and undefining the same thing
>   would be wasteful and time-consuming.  i think there was also some
>   consideration of clearing things out of the middle of the hash table
>   (the same reason given for not being able to remove a file name from
>   the string pool unless it is the very last thing put onto the list).
>   i will try to look up the reference if that is considered useful.

In TeX's errorlog, I found the following which might shed some light
on the topic.

Denis.

* 28 Aug 1979
  ...
S422\>403. Correct a serious |\gdef| bug:
        Control sequences don't obey a last-in-first-out
        discipline, so \TeX\ loses things from the hash table when deleting a
        control sequence. @259
# To fix this, I either need to restrict \TeX\ (so that
        |\gdef| can be used inside a group only for control sequences already
        defined on the outer level) or need to change the hash table algorithm.
        Although all applications of \TeX\ known to me will agree to the
        former restriction, I've chosen the latter alternative,
        because it gives me
        a chance to improve the language: Control sequences
        of arbitrary length will now be recognized.

========================================================================
Date:         Fri, 18 Nov 1994 20:31:34 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: "Denis B. Roegel" <Denis.Roegel@LORIA.FR>
Subject:      an other suggestion

This might be interesting and quite easy to implement (I think):

\showdefinedcommands : show all the commands that have been defined
by \def, \edef, \let, etc.

It can be useful for debugging.

Denis.

========================================================================
Date:         Fri, 18 Nov 1994 19:58:07 BST
Reply-To: Philip Taylor <P.Taylor@Vax.Rhbnc.Ac.Uk>
From: Philip TAYLOR <CHAA006@VAX.RHBNC.AC.UK>
Subject:      Re: an other suggestion

>> This might be interesting and quite easy to implement (I think):
>> \showdefinedcommands : show all the commands that have been defined
>> by \def, \edef, \let, etc.
>> It can be useful for debugging.

Or perhaps even \showallknowncontrolsequences? It could tag each
with its type: primitive, macro, chardef'd, etc?  If you walked
through the hash table they'd come out in a strange order, but I'm
not sure you'd want the overhead of sorting them...

I can't say I'm enthusiastic at the thought of these, but is there
a general demand for either the simple or the full-blown version?

                                        ** Phil.

========================================================================
Date:         Fri, 18 Nov 1994 16:39:52 EDT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@vm.gmd.de>
From: Jerry Leichter <leichter@LRW.COM>
Subject:      Re: an other suggestion

        >> This might be interesting and quite easy to implement (I think):
        >> \showdefinedcommands : show all the commands that have been defined
        >> by \def, \edef, \let, etc.
        >> It can be useful for debugging.

        Or perhaps even \showallknowncontrolsequences? It could tag each
        with its type: primitive, macro, chardef'd, etc?  If you walked
        through the hash table they'd come out in a strange order, but I'm
        not sure you'd want the overhead of sorting them...

        I can't say I'm enthusiastic at the thought of these, but is there
        a general demand for either the simple or the full-blown version?

I'd suggest something much simpler, but also more general:  Include \dump in
all versions of TeX.  The initex/virtex distinction is simply not worth the
bother of retaining any more - the memory differences are trivial in modern
terms.  \dump should ideally also be extended to allow dumping from inside of
a group.

Once you do this, it becomes possible to write programs to analyze format
files.  Since the analysis programs would not be part of TeX proper, they can
be as elaborate as anyone might want to make them.  Sorting would be no
problem, for example.

How about a control sequence cross-referencer?  If dumping inside of groups is
allowed, how about fancy stack tracebacks?  I could see this being used as the
basis of a general TeX debugging environment - the analogue of a Unix core
file.

None of this would cost anything in TeX itself, and except for the ability to
\dump inside a group, if added, would not even have an effect on whether the
resulting E-TeX is properly "TeX", since it would be invisible to any possible
trip test.
                                                        -- Jerry

========================================================================
Date:         Sat, 19 Nov 1994 13:12:45 MEZ
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Werner Lemberg <A7621GAC@AWIUNI11.EDVZ.UNIVIE.AC.AT>
Subject:      Re: an other suggestion
In-Reply-To:  Message of Fri, 18 Nov 1994 19:58:07 BST from
              <CHAA006@VAX.RHBNC.AC.UK>

I think it would be quite nice to have a dump facility:

if you say \TeXdump, you get a complete description of the registers,
defined commands etc. comparable to a core file. TeX should exit then.


    Werner

========================================================================
Date:         Mon, 21 Nov 1994 14:40:02 BST
Reply-To: Philip Taylor <P.Taylor@Vax.Rhbnc.Ac.Uk>
From: Philip TAYLOR <CHAA006@VAX.RHBNC.AC.UK>
Subject:      Re: an other suggestion

[Jerry Leichter wrote: ]

>> I'd suggest something much simpler, but also more general:  Include \dump in
>> all versions of TeX.  The initex/virtex distinction is simply not worth the
>> bother of retaining any more - the memory differences are trivial in modern
>> terms.  \dump should ideally also be extended to allow dumping from inside of
>> a group.

It is interesting that Nelson Beebe has also proposed that \dump/\restore
should be more generally accessible as well.  Clearly we must look into this.

                                        ** Phil.

========================================================================
Date:         Mon, 21 Nov 1994 16:26:09 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: David Carlisle <carlisle@CS.MAN.AC.UK>
Subject:      another creaping feature

One really useful feature (almost a bug fix, really) would be
a new primitive, say \something, which had the same effect as \relax
except that <optional \something's> was added to the end of the bnf
descriptions for count and skip etc.

Then if you wanted to return the maximum of two numbers you could go

\def\maxnum#1#2{\ifnum#1\something>#2\something#1\else#2\fi\something}

This is currently terribly difficult to do in TeX. in fact I am not
sure it is possible in full generality.

You can not terminate #1 or #2 with \relax as that leaves a token
which gets in the way, you can not use <space> as that will only be
eaten up if the arguments are literal digit strings, not internal
registers.

An alternative would be to use \relax instead of a new csname, but
that would probably break too much existing code unfortunately.

David

========================================================================
Date:         Mon, 21 Nov 1994 17:52:56 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Piet van Oostrum <piet@CS.RUU.NL>
Subject:      Re: another creaping feature
In-Reply-To:  <199411211638.AA27566@relay.cs.ruu.nl>

>>>>> David Carlisle <carlisle@cs.man.ac.uk> (DC) writes:

DC> One really useful feature (almost a bug fix, really) would be
DC> a new primitive, say \something, which had the same effect as \relax
DC> except that <optional \something's> was added to the end of the bnf
DC> descriptions for count and skip etc.

DC> Then if you wanted to return the maximum of two numbers you could go

DC> \def\maxnum#1#2{\ifnum#1\something>#2\something#1\else#2\fi\something}

DC> This is currently terribly difficult to do in TeX. in fact I am not
DC> sure it is possible in full generality.

DC> You can not terminate #1 or #2 with \relax as that leaves a token
DC> which gets in the way, you can not use <space> as that will only be
DC> eaten up if the arguments are literal digit strings, not internal
DC> registers.

Can't this be solved by using \number?

I think in your example the first \something is unnecessary, as the number
is terminated by ">".

\def\maxnum#1#2{\ifnum#1>\number#2 \number#1\else\number#2\fi }

Except that this would give a decimal number rather than a \count or
internal integer in some cases.
--
Piet van Oostrum <piet@cs.ruu.nl>

========================================================================
Date:         Mon, 21 Nov 1994 17:38:08 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: David Carlisle <carlisle@CS.MAN.AC.UK>
Subject:      Re: another creaping feature
In-Reply-To:  <9411211728.AA24616@m1.cs.man.ac.uk> (message from Piet van
              Oostrum on Mon, 21 Nov 1994 17:52:56 +0100)

> Can't this be solved by using \number?
Not in full generality, no. If provoked I could dig out my test cases
of what goes wrong with various definitions of \maxnumber...


One might want to insist that it actually returns #1 or #2, not just
an equal value (thus discounting your code)

eg you might want this to work

\maxnum{\count0}{\count2}=0

ie set either \count0 or \count2 to 0...

Also what do you do about \skip assignments, there you can only
currently stop the lookahead using \relax, which often is one token
too many in further processing.

David

========================================================================
Date:         Mon, 21 Nov 1994 21:54:07 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      \showcsname...\endcsname

\showcsname ... \endcsname

In an increasingly popular macro package the authors make intense use of
untypeable (and sometimes almost unreadable) control sequences with
spaces, backslashes and other strange tokens in. For analysis I like to
have

\showcsname....\endcsname, which acts like \show.

Maybe it should be accompagnied by a

\meaningcsname....\endcsname

for use in programmes.

--J"org Knappen.

========================================================================
Date:         Mon, 21 Nov 1994 21:17:37 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      An alternative to the creaping features

What about something like:
\ifevaluate{<boolean expression>}....\else....\fi ?

This would give a general and flexible \if whith much more comfort then you
have now. Of course some dirty tricks aren't possible with this one, like
pushing tokens from the condition to the {true} branch.

The boolean expression should allow for the usual operators like
.not., .and., .or., .xor., =, >, <, <=, etc., if feasable it should also
allow the evaluation of arithmetic expressions. Some functions are needed
to get information old TeX \if's know now, I propose the name
\query<whatever> to these functions.

At the moment I see need for the following \query<whatever> functions:

\queryeof    returns `1' if eof, `0' else
\querymode   returns `0' in the infamous `no mode' (do we need to
                           differentiate finer here?
                     `1' in vertical mode
                     `2' in restricted vertial mode
                     `3' in horizontal mode
                     `4' in restricted horizontal mode
                     `5' in math mode
                     `6' in restricted math mode
  With \querymode \ifmmode, \ifhmode, \ifvmode, and \ifinner can be emulated.
\querydefined{\cs}   `1' if defined, `0' else
\querycsname...\endcsname      "        "

--J"org Knappen.

========================================================================
Date:         Mon, 21 Nov 1994 23:17:55 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: "Denis B. Roegel" <Denis.Roegel@LORIA.FR>
Subject:      show space tokens in \tracingmacros

When you have to debug some weird encoding issue in LaTeX2e,
you soon realize that there are internal command names
containing a trailing white space. The problem arises when you
want to follow some trace given by \tracingmacros.

For instance, let's imagine two control sequences \cs-one and \cs-one ,
the second having a white space (see it ?) at the end.
When you trace expansions, you get something like:

\cs-one  -> ...

and

\cs-one   -> ...

I mean, the only difference is the slightly visible shift of the arrow.

It would be nice if there was some way to show more explicitely these
space tokens.

Denis.

========================================================================
Date:         Tue, 22 Nov 1994 10:17:03 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Piet van Oostrum <piet@CS.RUU.NL>
Subject:      Re: show space tokens in \tracingmacros
In-Reply-To:  <199411212220.AA03823@relay.cs.ruu.nl>

>>>>> "Denis B. Roegel" <Denis.Roegel@loria.fr> (DBR) writes:

DBR> When you have to debug some weird encoding issue in LaTeX2e,
DBR> you soon realize that there are internal command names
DBR> containing a trailing white space. The problem arises when you
DBR> want to follow some trace given by \tracingmacros.

DBR> For instance, let's imagine two control sequences \cs-one and \cs-one ,
DBR> the second having a white space (see it ?) at the end.
DBR> When you trace expansions, you get something like:

DBR> \cs-one  -> ...

DBR> and

DBR> \cs-one   -> ...

DBR> I mean, the only difference is the slightly visible shift of the arrow.

DBR> It would be nice if there was some way to show more explicitely these
DBR> space tokens.

Actually, I think the tracing mechanism is defective in more serious ways.
It is very difficult to track where you are in a deeply nested macro
expansion sequence. So selective tracing of macros should be possible and
the run-time nesting structure should be visible. Also assignments should
be tracable (i.e. the value assigned should be printed).

The tracing system may have been sufficient for plain TeX, but it is in no
way up to modern software engineering standards in cases like latex2e.
--
Piet van Oostrum <piet@cs.ruu.nl>

========================================================================
Date:         Tue, 22 Nov 1994 10:21:12 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Piet van Oostrum <piet@CS.RUU.NL>
Subject:      Re: \showcsname...\endcsname
In-Reply-To:  <199411212205.AA03674@relay.cs.ruu.nl>

>>>>> "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE> (JKM) writes:

JKM> \showcsname ... \endcsname
JKM> In an increasingly popular macro package the authors make intense use of
JKM> untypeable (and sometimes almost unreadable) control sequences with
JKM> spaces, backslashes and other strange tokens in. For analysis I like to
JKM> have

JKM> \showcsname....\endcsname, which acts like \show.

JKM> Maybe it should be accompagnied by a

JKM> \meaningcsname....\endcsname

How would this differ from \expandafter\show\csname ....\endcsname
\expandafter\meaning\csname ....\endcsname?
--
Piet van Oostrum <piet@cs.ruu.nl>

========================================================================
Date:         Tue, 22 Nov 1994 22:17:34 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: "J%org Knappen, Mainz" <KNAPPEN@VKPMZD.KPH.UNI-MAINZ.DE>
Subject:      Re: \showcsname...\endcsname

Piet's suggestion:

  How would this differ from \expandafter\show\csname ....\endcsname
  \expandafter\meaning\csname ....\endcsname?

just works fine for me, so I can withdraw this proposal.

--J"org Knappen.

P.S. Thanks for that, it really helps in studying LaTeX2e code.

========================================================================
Date:         Wed, 23 Nov 1994 15:01:12 BST
Reply-To: Philip Taylor <P.Taylor@Vax.Rhbnc.Ac.Uk>
From: Philip TAYLOR <CHAA006@VAX.RHBNC.AC.UK>
Subject:      Another idea for e-TeX: \traceingfileio

Having put up the so-called `patch level 4' of LaTeX-2e, I found it expedient
to allow full sub-directory searching... This was a mistake, since LaTeX-2e
proceeded to find LTHyphen.Cfg in some arcane unsupported Cyrillic
sub-directory, but that is by the by...

Rather more importantly, TeX can now appear to take a finite-but-unbounded time
to find a file that it used to find almost instantaneously.  So what I propose,
specifically bearing in mind the possible requirements of TWG-TDS, is a new
primitive \tracingfileio: differing positive values would cause greater or
lesser verbosity, but basically it would shew each attempt to open a file,
including the particular path which it is currently traversing.  I would
suggest that one use of the granularity would be to differentiate between
\input, \openin and \font (have I missed any?).

                                        ** Phil.

========================================================================
Date:         Wed, 23 Nov 1994 16:45:21 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Bernd Raichle <Raichle@INFORMATIK.UNI-STUTTGART.DE>
Subject:      Re: Another idea for e-TeX: \traceingfileio
In-Reply-To:  Philip TAYLOR's message of Wed, 23 Nov 1994 15:01:12 BST
              <9411231503.AA28121@ifi.informatik.uni-stuttgart.de>

on Wed, 23 Nov 1994 15:01:12 BST, Philip TAYLOR <CHAA006@VAX.RHBNC.AC.UK> said:
[...]
Phil> Rather more importantly, TeX can now appear to take a finite-but-unbounded
 time
Phil> to find a file that it used to find almost instantaneously.  So what I
 propose,
Phil> specifically bearing in mind the possible requirements of TWG-TDS, is a
 new
Phil> primitive \tracingfileio: differing positive values would cause greater or
Phil> lesser verbosity, but basically it would shew each attempt to open a file,
Phil> including the particular path which it is currently traversing.  I would
Phil> suggest that one use of the granularity would be to differentiate between
Phil> \input, \openin and \font (have I missed any?).

The file name and searching part of TeX is highly _implementation
dependent_ and in the moment the code to search files in a list of
directories---probably extended by recursive subdirectory searching---
is included through the TeX.web change file of the implementation or
some separate routines (e.g. Karl Berry's kpathsea(rch) routines used
in web2c).

What we can do is to give the TeX implementors some "hooks" in TeX to
enable some additional debug output in their routines... if the file
search routines provide it.
These "hooks" are comparable with the |fix_date_and_time| procedure,
providing the initial settings for the \time, \day, \month, \year
registers, whose default code in TeX.web (returning 12am 07/04/1776)
has to be replaced by some implementation dependent code.


Questions to be answered:

 - Should we try to enable/disable additional implementation dependent
   debugging output using some TeX registers/primitive commands?
 - Standardized form of the output or some conventions?
   Which ones?
 - Hooks for implementors:
   registers as flags, like \tracing..., or primitive commands?

Bernd

========================================================================
Date:         Wed, 23 Nov 1994 11:33:03 -0500
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: bbeeton <BNB@MATH.AMS.ORG>
Subject:      Re: Another idea for e-TeX: \traceingfileio
In-Reply-To:  <01HJTEODUK3MEBP7TJ@MATH.AMS.ORG>

bernd raichle points out that there are some features of tex
that are (legitimately) implementation dependent, including
the treatment of \openin vs. \input.  he proposes that some
"hooks" be provided in nts to regularize some such features,
and asks some questions:

 - Should we try to enable/disable additional implementation dependent
   debugging output using some TeX registers/primitive commands?
 - Standardized form of the output or some conventions?
   Which ones?
 - Hooks for implementors:
   registers as flags, like \tracing..., or primitive commands?

i can't answer these questions directly, but would like to
encourage agreement among implementors to present such features
in a form as similar as possible to the macro writer.  it's
really no fun trying to debug problems that arise because of
system dependencies on systems *other* than the one(s) one is
used to using.  with tugboat, i've gotten used to the differences
in end-of-line markers (and routinely convert all files from
certain authors before trying to process them) and similar,
but there are still surprises, and they waste a lot of time.
a uniform presentation -- when possible -- would mean that i
might really be able to get help from other people who don't
have exactly the same setup as i do, a luxury that i don't
now enjoy.
                                                -- bb
p.s. i will still claim publicly that "from tex, you get the
same output from the same input", but it ain't true, guys!
not with the inventive minds and highly-tuned personal systems
that tugboat authors revel in.

========================================================================
Date:         Thu, 24 Nov 1994 00:13:09 +0000
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Timothy Murphy <tim@MATHS.TCD.IE>
Subject:      Re: Another idea for e-TeX: \traceingfileio
In-Reply-To:  <01HJTRI6R1PE00EB6T@mailgate.ucd.ie> from "Bernd Raichle" at Nov
              23, 94 04:45:21 pm

> What we can do is to give the TeX implementors some "hooks" in TeX to
> enable some additional debug output in their routines... if the file
> search routines provide it.

In my view this request is completely misconceived.
The sought-for debug facilities are already present in unixTeX
(in kpathsea-2.4).

I have yet to see a suggestion made by the NTS people
which I both understand and agree with.

========================================================================
Date:         Thu, 24 Nov 1994 13:26:00 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: "Ciar\\'an \\'O Duibh\\'in" <Csg0070@QUEENS-BELFAST.AC.UK>
Subject:      Transforming glyphs in dvi and vpl files

I've already sent this suggestion to one or two members of NTS, but I've
just discovered NTS-L, where I should have sent it in the first place!
Apologies if something like this has already been discussed here.

I'd like to proposed an enhancement to dvi file format:

At present, a dvi file can contain instructions to shift a glyph (but
I don't think any other operations on a glyph are allowed). I'd like
to propose three (two really, each is the product of the other two):

Allow a glyph to be:
1. mirrored in a vertical axis, placed centrally;
2. mirrored in a horizontal axis, placed at half the x(?)-height;
3. rotated by 180 degrees about the point of intersection of those axes.

This would greatly increase the power of vpl files (e.g. define schwa by
rotating e), and I hope that it would be possible for drivers to implement.

Ciar\'an \'O Duibh\'in.

========================================================================
Date:         Thu, 24 Nov 1994 13:54:16 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Angus Duggan <angus@HARLEQUIN.CO.UK>
Subject:      Transforming glyphs in dvi and vpl files
In-Reply-To:  <14173.199411241340@holly.cam.harlequin.co.uk>

"Ciar\\'an \\'O Duibh\\'in" writes:
>I've already sent this suggestion to one or two members of NTS, but I've
>just discovered NTS-L, where I should have sent it in the first place!
>Apologies if something like this has already been discussed here.
>
>I'd like to proposed an enhancement to dvi file format:
>
>At present, a dvi file can contain instructions to shift a glyph (but
>I don't think any other operations on a glyph are allowed). I'd like
>to propose three (two really, each is the product of the other two):

I don't know what you mean by "shift a glyph". The DVI format has instructions
to put a character at the current position without altering the position, and
to put a character at the current position, adjusting the current horizontal
position by the width of the character, taken from the TFM file.

>Allow a glyph to be:
>1. mirrored in a vertical axis, placed centrally;

What is centrally? The TFM file has the height, width and depth of the
character, but there need not be any relationship between these dimensions and
the bounding box of the area marked by the glyph.

>2. mirrored in a horizontal axis, placed at half the x(?)-height;

The x-height is only stored as a fontdimen, by convention. Non-text fonts are
at liberty to use the fondimen for anything they want.

>3. rotated by 180 degrees about the point of intersection of those axes.
>
>This would greatly increase the power of vpl files (e.g. define schwa by
>rotating e), and I hope that it would be possible for drivers to implement.

I very much doubt that it would be easy to agree on any proposal like this. I
doubt whether any extensions to the DVI format apart from already existing
ones (TeX-XeT, and \special conventions) will get significant support from
driver writers.

>Ciar\'an \'O Duibh\'in.

a.
--
Angus Duggan, Harlequin Ltd., Barrington Hall,  | INET: angus@harlequin.co.uk
Barrington, Cambridge CB2 5RG, U.K.             | PHONE: +44(0)1223 873838

========================================================================
Date:         Thu, 24 Nov 1994 13:56:03 +0000
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Sebastian Rahtz <Sebastian.Rahtz@CL.CAM.AC.UK>
Subject:      Re: Transforming glyphs in dvi and vpl files
In-Reply-To:  Your message of "Thu, 24 Nov 1994 13:26:00 GMT."
              <"swan.cl.cam.:161610:941124134520"@cl.cam.ac.uk>

i see why there is the desire to play with glyphs in the dvi file, but
is it really worth the effort? we know we can do this easily in
virtual fonts whose only drawback is that they are tied to a driver
that can implement the \special commands. so why not just work on
standardizing \specila commands for rotation and mirroring, and you
can leave the dvi format alone.

sebastian

========================================================================
Date:         Thu, 24 Nov 1994 17:06:50 +0100
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Joachim Schrod <schrod@ITI.INFORMATIK.TH-DARMSTADT.DE>
Subject:      Re: Transforming glyphs in dvi and vpl files
In-Reply-To:  <199411241342.OAA41041@rs3.hrz.th-darmstadt.de> from "Ciar\\'an
              \\'O Duibh\\'in" at Nov 24, 94 01:26:00 pm

Ciar\'an \'O Duibh\'in wrote:
>
> Allow a glyph to be:
> 1. mirrored in a vertical axis, placed centrally;
> 2. mirrored in a horizontal axis, placed at half the x(?)-height;
> 3. rotated by 180 degrees about the point of intersection of those axes.

Others commented already of the problems of the terms `centrally' and
`x-height' in DVI files. I want to add

 -- DVI drivers are not required (and should not!) to read TFM files,
    so they don't have access to fontdimens.

Btw, if we adopt your proposal; the next thing that'll be wanted is
rotating by 90 degrees. (I bet because that was brought up a few
dozen times before...) Before anybody adds this proposal keep in mind
that we have devices with non-square ratios where simple matrix
transformation does not work.

Cheers,
        Joachim
        [ex-secretary of ex-committee on DVI Driver Standards]

--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Joachim Schrod                  Email: schrod@iti.informatik.th-darmstadt.de
Computer Science Department
Technical University of Darmstadt, Germany

========================================================================
Date:         Mon, 28 Nov 1994 13:50:00 GMT
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: "Ciar\\'an \\'O Duibh\\'in" <Csg0070@QUEENS-BELFAST.AC.UK>
Subject:      Re: Transforming glyphs in dvi and vpl files

Despite the generally unfavourable comment, I'm not dissuaded. I am not being
flippant in asking for characters to be turned upside-down, as I typeset
quite a lot of phonetics (and I know there are phonetic fonts). But be
reassured that I can't think of any useful character made by rotating a
common character through 90 degrees!

I should also have said that I am looking at this from the viewpoint of
virtual font construction. Perhaps it was misleading to say "dvi format",
when I really meant "vpl format". (I did so because there's already a section
on "dvi format" in the NTS-L FAQ, and Knuth stated in his "Virtual Fonts"
article that "it's easy for dvi drivers to read vf files, because vf format
is similar to the pk and dvi formats they already deal with". And I think I
read that what you are allowed to do in vpl files is limited by what you
can do in dvi files.)

What I meant by "shifting a glyph" is that the dvi file can contain
instructions to move anywhere before setting it, and then move back again.
Turning to vpl files, here's how ptmrq.vpl defines A-acute - note the
MOVERIGHT and MOVEDOWN:

(CHARACTER O 301
   (CHARWD R 0.721997)
   (CHARHT R 0.900989)
   (MAP
      (PUSH)
      (SETCHAR C A)
      (POP)
      (PUSH)
      (MOVERIGHT R 0.1939945)
      (MOVEDOWN R -0.21399)
      (SETCHAR O 302)
      (POP)
      (MOVERIGHT R 0.721997)
      )
   )

What I would like to be able to do, in making a vpl file for phonetics
from a normal alphabetic font, and needing turned m (i.e. rotated through
180 degrees), turned h, vertically-flipped (or mirrored) y, horizontally-
flipped e, etc. would be something like this - any suitable syntax will do:
     (SETCHAR (TURN C m))   or
     (SETCHAR (VFLIP C y))   or
     (SETCHAR (HFLIP C e))
A nice point is to compare these transformations with what can be done
with metal type. A turn is no problem there, which is presumably why so
many new symbols are made that way. But flipping is not possible with
physical type, though it should be with computers.

The question most people raised was the one I hoped they might answer for
me: about what point should the glyph be turned, or in what axes should it
be flipped? I've come to the conclusion that neither general fontdimens
(quadwidth, xheight) nor individual widths/heights/depths are adequate,
even if available. The vf designer will have to say, in each individual
case, where the axes are. And this is ok. Let's say I want to turn the
"m" of 10pt Adobe Times Roman. This has a width of 0.77799 design units
(tens of points) and a height of 0.453498 design units. So I might wish
to say in my vpl file
         (SETCHAR (TURN 0.388995 0.226749 C m))
If the result of those values didn't look right (e.g. if the character
extended outside its nominal width or height), I could adjust the values,
or apply an additional MOVERIGHT or MOVEDOWN. In fact, we could make all
flips and turns relative to the reference point, and then the last example
would be equivalent to:
         (MOVERIGHT 0.77799) (MOVEDOWN -0.453498) (SETCHAR (TURN C m))
Or maybe turns and flips should be relative to the centre of the glyph's
width and height, so that the outline of the box stays where it is. In that
case this example becomes once again simply
         (SETCHAR (TURN C m))
and an additional MOVERIGHT and MOVEDOWN will always achieve the required
effect if further adjustment is necessary (a MOVEDOWN would certainly be
needed for turned h, for example).

I didn't fully understand the comment:
> why not just work on standardizing \special commands for rotation and
> mirroring, and you can leave the dvi format alone.
If possible, that would be fine. But aren't specials used for device-specific
features? The drivers I use are dviscr and dvips. Dviscr has no specials
for rotation and mirroring, and I don't see how adding them would be any
easier than dealing with the proposed extension to dvi (recte vpl) format.
I'm thinking of bitmap fonts just as much as outline fonts, by the way.

Ciar\an \'O Duibh\'in.

========================================================================
Date:         Mon, 28 Nov 1994 14:58:59 MEZ
Reply-To: NTS-L Distribution list <NTS-L%DHDURZ1.BITNET@dearnpc.gmd.de>
From: Werner Lemberg <A7621GAC@AWIUNI11.EDVZ.UNIVIE.AC.AT>
Subject:      Re: Transforming glyphs in dvi and vpl files
In-Reply-To:  Message of Mon, 28 Nov 1994 13:50:00 GMT from
              <Csg0070@QUEENS-BELFAST.AC.UK>

On Mon, 28 Nov 1994 13:50:00 GMT Ciar\\'an \\'O Duibh\\'in said:
>Despite the generally unfavourable comment, I'm not dissuaded. I am not being
>flippant in asking for characters to be turned upside-down, as I typeset
>quite a lot of phonetics (and I know there are phonetic fonts). But be
>reassured that I can't think of any useful character made by rotating a
>common character through 90 degrees!
>

What about Chinese/Japanese?

    Werner

PS: I know, I know, TeX is not really used to these languages :-)