From a3b7bac23ec996ef6e36711839c9f5bb9a22519b Mon Sep 17 00:00:00 2001 From: Karl Berry Date: Sat, 23 May 2009 00:40:02 +0000 Subject: added directories git-svn-id: svn://tug.org/texlive/trunk@13416 c570f23f-e606-0410-a88d-b1316a301751 --- Master/texmf-dist/doc/etex/base/NTS-FAQ | 1015 +++++++++++++++++++++++++++++++ 1 file changed, 1015 insertions(+) create mode 100644 Master/texmf-dist/doc/etex/base/NTS-FAQ (limited to 'Master/texmf-dist/doc/etex') diff --git a/Master/texmf-dist/doc/etex/base/NTS-FAQ b/Master/texmf-dist/doc/etex/base/NTS-FAQ new file mode 100644 index 00000000000..1dd051f1e83 --- /dev/null +++ b/Master/texmf-dist/doc/etex/base/NTS-FAQ @@ -0,0 +1,1015 @@ +Date: Tue, 31 Jan 1995 21:15:16 +0100 +Sender: NTS-L Distribution list +From: "J%org Knappen, Mainz" +Subject: Frequently asked questions of NTS-L, 5th edition +X-To: nts-l +To: Multiple recipients of list NTS-L + + Frequently Asked Questions of NTS-L + +Fifth edition +Date: 31-JAN-1995 +Archive name: nts-l-faq +Currently maintained by: knappen@vkpmzd.kph.uni-mainz.de (J%org Knappen) + +Remark about the format: + +This faq is divided into several sections and subsections. Each section +contains a subsection general with some ideas which have not yet been +discussed. I added a date to some subsections to allow you to retrieve +fuller discussions from the archives. The transactions of this group are +archived on + + ftp.th-darmstadt.de [130.83.55.75] *) + directory pub/tex/documentation/nts-l + +Each file in this directory is named yymm, where (guess :-) yy is the +year and mm is the month when the mail arrived. (I.e., all postings +of one month are bundled in one file.) +*) Avoid using the number above ... it is subject to changes. + +Related stuff which is very worth reading you can find on the CTAN archives +under tex/info/tex-implementors. In addition, I recommend reading the list +of TeX bugs (tex-archive/systems/knuth/errata/tex82.bug). + +-1. Contents + +0. About NTS +1. Proposed features of a New Typesetting system +1.1. Improvement of Quality +1.2. Internationality +1.3. New Look and Feel +1.4. Changing the ligaturing algorithm +1.5. Writing more than one dvi-file +1.6. Anchors +1.7. dump/restore mechanism +2. Proposed additions to TeX (concrete new primitives) +2.1. \lastmark etc. +2.2. \system +2.3. \skylineskiplimit, \skylinehorizontallimit +2.4. \directioncode +2.5. \textcode +2.6. \afterfi +2.7. \interactionmode +2.8. \mathspacing +2.9. \inputescapechar +2.10. \middle +2.11. \outputunit +2.12. \protected +2.13. \scantokens +2.14. \deferred +2.15. \everyeof +2.16. \readline +2.17. \evaluate +2.18. \ifevaluate +2.19. \everyeof +2.20. \fancyprompt +3. Metaremarks +3.1. TeX is not perfect +3.2. In which language shall NTS be written +3.3. The TeX language +3.4. The TeX engine +3.5. Extensions and Enhancements +4. Deviations +4.1. Automated Kerning +4.2. About Lout +5. Proposed changes to METAFONT +5.1. Writing to auxiliary files +6. Proposed changes to the tfm file format +6.1. Vertical kerning +6.2. Cross-font ligatures +7. Proposed changes to the dvi file format +7.1. Horizontal and Vertical Mirroring +7.2. Rotation of a glphy by 180 degrees +8. Additions to the TeX kit +8.1. dvicopy +8.2. dv2dp and dp2dv +8.3. gftotxt +8.4. qdtexvpl +8.5. fontinst +8.6. afmtotfm +8.7. dvipaste +8.8. METAPOST +8.9. Tie +8.10. dvi2dvi +9. Existing extensions to TeX +9.1. TeX-XeT +9.2. TeX--XeT +9.3. MLTeX +9.4. SiSiSi +9.5. Japanese TeX + +0. About NTS (Mar 93, see also Jul 92) + + At DANTE '93, held at the Technical University Chemnitz last week, Joachim + Lammarsch, President of Dante, announced that the NTS project which had been + started under the aegis of DANTE, was to be re-formed under a new + co-ordinator, Philip Taylor. The old core group, announced at the previous + annual DANTE meeting, was to be dissolved, and a new core group established. + Membership of the new core group will not be restricted to DANTE members, + but will instead be offered to various well-known names (and some + lesser-known!) in the international TeX community. + + see also: + F. Mittelbach: E-TeX Guidelines for future TeX, TUGboat v11n3 (1990) + P. Taylor: The future of TeX, EuroTeX'92 Prag (Proceedings); reprinted + in TUGboat v13n4, 433 (1992) + + As of September 1994, there are two activities going on, the ETeX group + is working on a extension of TeX and is going to produce a first ETeX soon. + The NTS group takes the path to reimplement TeX in common LISP to get + a deeper understanding of how the modules of TeX are cooperating which + eachother. + + Independently, the Omega project was launched to produce a typesetting system + which uses unicode as internal code and can handle arbitrarily encoded input + via filters. + + The beforementioned projects were presented at the 1994 TUG meeting at Santa + Barbara and at the EuroTeX'94 conference at Gdansk. For more information, + consult the respective proceedings. For the Omega project exists a mailing + list, omega@ens.fr. To subscribe, send an e-mail to LISTSERV@ens.fr. + + Omega is now announced to be presented at March 16, 1995 at CERN (Geneva). + +1. Proposed features of a New Typesetting system + +1.1. Improvement of Quality + +1.1.0 General: + Optimised page breaking, avoiding ``rivers'', letterspacing (see also 4.1), + Hyphenation (Haupt- und Nebentrennstellen), grid typesetting + +1.1.1 Skyline approach to line breaking (Mar 93) + +You can break paragraphs as usual with the current model, where all +lines are simple rectangular boxes. If there's no necessity to insert +\lineskip, then you don't have to look at the skyline. Only if two +lines are too near (e.g. distance<\lineskiplimit), you have to look +into the two rectangular boxes and to check if the boxes inside +overlap at one or more places. +For the worst case (i.e., you have to look at the skyline for all +pairs of lines) processing the skyline model consumes a lot of process +time, but this shouldn't hinder us to test this idea and look at the +results. + +Btw, the skyline model seems to be easy to implement in the current +TeX, because we need only some changes when the finally broken lines +of the paragraph are put on the vertical list. There are more changes +needed in the code, if the line break should be changed for the cases +where it is possible to avoid an overlap with other break points, but +IMHO it's nonetheless a relatively small change. + +Additionally you have to introduce some new parameters. I think of +something like: + \skylineskiplimit (b) + minimum vertical distance between two boxes + \skylinehorizontallimit (a) + minimum horizontal distance + + +line 1: ------------ + % % + % % ---------- + ------- <== (a) ==> % % + ~ % % + (b) % ------- + v % + ---------------------- +line 2: + +and other parameters, but the necessary parameter set, realization, +etc. for "skylines" are subject of discussion. + + +1.2. Internationality + +1.2.0 General: + Typesetting in arbitrary directions, unicode support (16bits), ISO10646 + support (32bits), ligatures pointing to other fonts, vertical kerning, + better accent handling (\topaccent and \botaccent) + + Remark: UTF-8 (UNICODE) can be handled with `TeX classic', LaTeX2e + support is provided by the CJK package written by Werner Lemberg. + +1.2.1 Supporting TeX--XeT primitives for right to left typesetting + TeX--XeT is an existing extension to TeX supporting right-to-left + typesetting an producing a usual dvi-file. TeX--XeT is written by + P. Breitenlohner and freely available. It is different from TeX-XeT + (one hyphen only). Allthough TeX will be frozen at version $\pi$, + this is not true for TeX--XeT. (see also 9.2) + +1.3. New Look and Feel + +1.3.0 General + Windows support, wysiwyg-like features + +1.3.1 Interaction with the operating system and other programmes + see 2.2. \system + +1.4. Changing the ligaturing algorithm + Replace the (IMHO over-)optimized ligature builder/kerning routines in + TeX by routines which separate between the building of ligatures and + the insertion of kerns between the characters/ligatures. + + This can be realized in a simple way by using two passes: in the + first pass the ligatures are built and in the second pass the + resulting ligatures and remaining single characters are used to + determine the necessary kerns. + + To ensure compatibility between e-TeX and TeX, it will be possible to + switch between the new and the current behaviour. + + Additionally a flag in the TFM file of each font can be used to + specify which behaviour is to be used for the font. This ensures that + "old" fonts with some tricky ligature/kerning programs depending on + the old behaviour can still be used with e-TeX. (I don't know if this + font dependent switching is really necessary. Comments, please!!) + + Example: + + A font contains the following ligatures and kerns: + + o " => ligature (o") (= \"{o}) + V o => kern(-smallkern) + V lig(o") => nothing + + Input: V o " + Output of current TeX: V kern(-smallkern) ligature(o") + Output with change: V ligature(o") + + Status: + + Bernd Raichle has written a simple, but running reimplementation of TeX's + ligature/kerning routine (in CommonLisp), which still waits to be + rewritten as a TeX.web change file. + The ligature builder/kerning routine is realized in one pass; kerns + are introduced in a delayed manner, i.e., after we are sure that + there's no possibility for a ligature. + Additionally there's a switch between the current TeX and the new + behaviour. (The TRIP test fails with the new behaviour.) + +PS: IMHO the ligature/kerning routines should be further changed to + remove the `shelf{}ful' anomaly (see TeXbook, exercise 5.1), i.e., + reinserting ligatures when words are hyphenated. + The change should allow ligatures for inputs like `f{}f' or + `f\relax f', which will simplify the macros in `german.sty', + Babel and changed macros for \", \', ... which are used to select + characters from DC fonts or other fonts with national characters. + +1.5. Writing more than one dvi-file (Nov 94) + I want to have TeX ready in the memory and avoid loading it anew and anew + for each run again which costs lots of startup time, if you have to load + every file 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 anything you want (start even another \level) and at last you say + \exit + which performes like \end, except that it restores exactly the state before + the last cloning. + To communicate some information to the waiting lion, 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, + whether a further run is necessary. Of course, you should device your format + to have a counter maxruns to avoid endless looping... + +1.6. Anchors (Nov 94) + 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. + +1.7. dump/restore mechanism + 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. + 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. + +2. Proposed additions to TeX (concrete new primitives) + +2.0. General (Jun 92, Jul 92, Aug 93, Nov 94) + A rather long list of proposed primitives (more or less worked out) was + posted by Karl Berry on 10-Jun-1992. It contains suggestions like: + \elseif (selfexplaining), \format{foo} (allow the author to select a format), + \host{name} \host{os} \host{type} \getenv to extract host information + \TeXversion, \usertime, \everyeof, and others. + + It is currently not possible to get some information about the current + mode of TeX and make conditionals dependent on it and/or restore it after + some action (see 2.7. \interactionmode). More of this kind are a + conditional or primitive to signal, when TeX is in "expand only" mode + (\edef, \mark, \write, ...), when TeX is scanning numbers (here I'm + thinking---and hating---german.sty's active doublequote, which can also + be used as a marker for hexadecimal numbers), when TeX is peeking for + some special tokens (first column in an \halign), etc... + + A list of new primitives, enhancements and extensions has been prepared + on the NTS meeting at Lindau in October 1994. It was posted to this list in + November 1994 and provoked plenty of discussions and additional suggestions. + Under the discussed primitves were \bind, \contents, \futuredef, + \ifdefined, \ifcsname ... \endcsname, \unless, \OSname, \defaultextension. + +2.1. \lastmark etc. (Jun 92, Jul 92) + Currently you cannot remove a \write or \mark or + \insert or rule from any list at all. If we allow them to removed, how + will the commands appear to the user? If we have \lastmark like + \lastbox, then perhaps we need a mark data type so that we can say something + like \setmark0=\lastmark. It will probably be difficult + in the case of \insert's to think of a good command syntax. + + Perhaps \lastpenalty, \lastkern, \lastskip should + remove the penalty, kern, skip, ... so that they are consistent with + \lastbox. Then \unpenalty, \unkern, and \unskip would be unnecessary. + (Of course most macro packages would probably want to reimplement them, + as macros: \def\unpenalty{\count@\lastpenalty}, + \def\unkern{\dimen@\lastkern}, \def\unskip{\skip@\lastskip}.) + +2.2. \system (Mar 93) + +2.2.0 General + Oops, this got rather longish, but this topic has caused plenty of traffic. + I decided to quote directly the positions of both sides. The subpoints are + 1. Pro 2. Contra 3. Syntax + +2.2.1 Pro + First comes the proposal as formulated by Phil Taylor: + + There has been much discussion on how a \system primitive might interact + with different operating systems, each with different functionality and a + different syntax. My idea was to extend the concept of a `TeX + implementation', which at the moment implies the creation and application + of a change-file to the master TeX source, to include an implementation- + specific macro library. Thus each implementor, as well as creating and + applying a change file, would also be responsible for mapping a well-defined + set of macros, through the \system primitive, to the syntax and + functionality of the operating system for which he or she has assumed + responsibility. To cite a specific example: + + Assume that in e-Lib (a hypothetical macro library to accompany e-TeX), + a macro \sys$delete_file {} is partially defined; then each + implementor would be responsible for mapping \sys$delete_file { + to his or her own implementation of \system. e-Lib would define the effect + and the result(s), \system would provide the interface, and the implementor + would be responsible for providing the mapping. + + The question has been asked: ``Why via \system and macros? Why not via + explicit primitives to carry out the various functions that are envisaged?'' + + To which I would suggest that the answer is ``Because `the various functions + which are envisaged' is both enormous (requiring many new primitives), and + yet not large enough (because no matter what functionality we posit, someone + will come up with an idea that has not been considered).'' By implementing + just one \system primitive, and an extensible e-Lib macro library, one can + create a robust and well-tested e-TeX whilst allowing new system interactions + to be added at the simplest points: through the implementation-independent + and implementation-specific components of e-Lib. + +2.2.2 Contra + And here's from the ``Minority Report'' (Tim Murphy and J"org Knappen) + + May I recall the immortal words of Ken Thompson, + "A program should do one thing, and do it well." (TM) + + I don't like the hackers to decide, making eTeX yet another programme from + which I can send e-mail and read news :-) Maybe people will tell me eTeX is + a fine operating system, but TeX version $\pi$ is the better typesetter :-) + + But there is another side of \system, I want to call it the monstrosity + side. Many people are thinking now, that TeX is a monster and difficult to + tame. \system will add to this monstrosity. It will create a new paradise + for hackers creating system hacks. And it will make people turn away from + eTeX and use other products, even if they are far less secure. (JK) + +2.2.3 Syntax + If a \system command is required, should it not have a similar syntax + and semantics to the a similar TeX command. I can't think of anything + else in TeX (prepares to be shown wrong) that expands in the mouth and + has side-effects. Should it not be like \read, \write etc. that is it + generates a whatsit that is obeyed at shipout, unless preceded by an + \immediate, in which case it is done immediately by the stomach. + There seem to be two obvious syntaxes, one like \write: + \system{foo} or \immediate\system{foo} + and one like \read: + \system{foo} to \baz or \immediate\system{foo} to \baz + The latter one would produce the exit code into \baz. Should this be + done with catcode 12 characters, or should it be done like \read, with + the current catcodes? + +2.3. \skylineskiplimit, \skylinehorizontallimit + see section 1.1.1 + +2.4. \directioncode (May 1993) + A \directioncode (with syntax analogous to \uccode, \lccode, sfcode) to be + assigned to each input character. The basic ones are + 0 -- transparent (space, full stop...) + 1 -- left-to-right (latin letters, digits...) + 2 -- right-to-left (hebrew letters, arab letters...), + a truly international NTS will also have codes for vertical typesetting + and some special cases. + + The question is how to use this idea consistently. One could extend the + notion of TeX's modes. Horizontal mode is in fact left-to-right mode, a + right-to-left mode is missing. To be complete, this mode will be equipped + with boxen and all the stuff TeX's left-to-right (aka horizontal) mode has. + + At the beginning of a paragraph NTS decides which mode to choose by the + \directioncode of the first input character. Sometimes the first character + will have the wrong code, in this case the insertion of an explicit + control sequence (like \lrbox{}) is necessary. If a character with another + directioncode occurs, NTS starts a \rlbox and finishes it as soon as a + character with the original \directioncode appears or at the end of the + paragraph. + + For the building of right-to-left tables a \rlalign is needed. + +2.5. \textcode (Sep 93, Nov 93) + Some of the character coding discussions in the Technical Working + Group on Multiple Language Coordination and some experiences I've made + with `german.sty' (specially the problems with an active doublequote + and hex integer constants!) lead to this _incomplete_ proposal/idea + for the following addition: + Introduce something like + \textcode (and \textchar & \textchardef) + which are the text (hmode) equivalent of TeX's \mathcode (and + \mathchar/\mathchardef) primitives. + + With an equivalent and appropriate implemented \textcode primitive + (with the choice to define a character as "pseudo-active"), it would + be possible to + * relate characters to different fonts + (using a generalized `fam' of \mathcode) + + * suppress expansion of active characters (it will only be + expanded, if it is read to form the hlist) + (using an equivalent \mathcode="8000 value) + [This point allows the use of e.g. a pseudo-active " + which expands to non-expandable tokens and it removes + the special construct \relax\ifmmode... for active + characters, too.] + +2.6. \afterfi (August 1993) + In the answer to an exercise of the ``Around the Bend'' series, Michael Downes + realised the non-existence of an \afterfi primitive (Note: He did not + demand it nor really miss it). Perhaps an \afterfi can + simplify some obscure mouth-only macros with nested conditionals??? + \afterfi should be expandable, because \if...\fi is expandable. + +2.7. \interactionmode (Nov 93, was: \currentinteractionmode) + Add a new count register \interactionmode, which reflects the user + interaction level with the following values: + <= 0 batch_mode + = 1 nonstop_mode + = 2 scroll_mode + >= 3 error_stop_mode + + The commands \batchmode...\errorstopmode, the "options" 'Q', 'R', 'S' + in the interactive error routine and all other TeX internal + interaction level changes (e.g. after an interruption) access this new + register. The level changes in the interactive error routine and the + old commands should always work, even if the symbol \interactionmode is + redefined (this means that the user can redefine \interactionmode, but the + commands \batchmode...\errorstopmode still work). + + Examples: + + \ifnum\interactionmode<1 \AskUser \else \UseDefault \fi + + {\interactionmode=0 % switch to \batchmode + \global\font\test=xyz10 % try to load font + }% % restore former interaction level + % ... now test if font has been loaded + % without error (i.e. != nullfont) + +2.8. \mathspacing (Nov 93) + Add a new count register array \mathspacing with 64 entries (we really + need only 64-8=56 entries, because some of them are never used, but to + simplify things 64 are used) with the following syntax: + + \mathspacing = % 0 <= <= 63 + + The spacing specified in number is inserted between the two + math atom types specified in number . The two numbers are coded + as + + = * 8 + + = ( ( * 256 + ) * 256 + + ) * 256 + + + This means that is easily expressed in octal and in + hexadecimal notation. + + <..._atom_type> is one of the following seven types: + + 0 ordinary 1 large operator + 2 binary operation 3 relation + 4 opening 5 closing + 6 punctuation 7 delimited subformula + + <..._spacing> can be specified separately for each of the four math + styles (display, text, script and scriptscript) with the following + values: + + 0 no space + 1 thin space (specified by \thinmuskip) + 2 medium space ( -- " -- \medmuskip) + 3 thick space ( -- " -- \thickmuskip) + + 4-255 reserved for other things + (e.g. other spacings and/or additional penalties, + like \relpenalty, \binoppenalty, ...) + + For more information see TeXbook, pp. 170f & Appendix G and TeX--The + Program, \S 764ff. + + Examples: (using TeX's standard spacing) + + Between an `ordinary' (= 0) and a `relation' (= 3) atom a thick + space (= 3) is inserted, but not in script or scriptscript style. + + \mathspacing '03 = "0033 + + Between a large operator (= 1) and an ordinary (= 0) atom a thin + space (= 1) is inserted: + + \mathspacing '10 = "1111 + + Necessary changes for the sketched proposal are very simple to + implement. + The syntax of \mathspacing is awful, but this is true for \mathcode, + \delimitercode, etc.etc., too. + +2.9. \inputescapechar (Nov 93, alternative names were proposed during + discussion) + Use two new internal count registers \inputescapechar and + \outputescapechar to specify the "escape" character to be used for + unprintable characters. + If \inputescapechar is not in [0..255], TeX's behaviour is used, + i.e., two equal characters with category 7 are used as a prefix for a + ~~x notated character, otherwise two characters with code + \inputescapechar are used for this prefix. + If \outputescapechar is not in [0..255], the character `~' is used + when an unprintable character has to be written. + + The default values of these two registers are + \inputescapechar = -1 + \outputescapechar = `~ + to be compatible with TeX's standard behaviour. + +2.10. \middle (Jan 94) + Generalize the syntax of \left \right + to allow one or more optional \middle delimiters, + \left \middle \right. + + The middle delimiter grows to the same height as the left and right ones. + Constructions of this kind are used throughout quantum mechanics (Dirac + notation), e.g. + $$ + \left\langle A \middle% \hat{O} \middle% B \right\rangle + $$ + By default, the \middle element is \mathrel, you can make it + \mathord by embracing it {\middle %}. + + +2.11. \outputunit (Dec 93) + \outputunit unit to be used when e-TeX shows some dimen or glue + value + Usage: \outputunit= (s. TeXbook p. 270) + Rationale: + + Currently TeX forces the user to think in points when it outputs any + dimen or glue value (e.g. when issueing an overfull hbox warning). + But a program should adapt to the conventions of the user instead the + other way round. The addition of \outputunit whould make TeX much + more user-friendly, since only a few people are thinking in points. + +2.12. \protected (new prefix for macro definitions) (Nov 94) + 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. + +2.13. \scantokens (Nov 94) + 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. + +2.14. \deferred (Nov 94) + 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. (See also 2.2.3) + +2.15. \everyeof {} + 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. + +2.16. \readline to (Nov 94) + Allows a single line to be read from an input file as if each character + therein had catcode 12. Intended to be used for verbatim copying + operations, in conjunction with \scantokens, or to allow error-free parsing + of `foreign' (non-TeX) files. + +2.17. \evaluate {} (Nov 94) + 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. + + Additional operations were proposed: trigonometric functions, square + root, pythagorean addition (METAFONT's `++'), angle{}. + +2.18. \ifevaluate{}....\else....\fi (Nov 94) + 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 to these functions. + + At the moment I see need for the following \query 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 vertical 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 (ditto) + +2.19. \everyeof {} + 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. + +2.20. \fancyprompt + allow configuration of the TeX prompt (default `*'), e.g. + *\fancyprompt{eTeX>} + eTeX> + +3. Metaremarks + +3.0. General + Remarks about group efforts vs. one person creating software (Mar 93), + ALGOL 68 as a warning example + +3.1. TeX is not perfect (Jun 92, Jul 92) + The discussion has taken place in June and July 1992. Several details were + worked out, where TeX could be improved. Another point of criticism was + the programming language of TeX in general, several participants prefer a + procedural language over a macro language. + +3.2. In which language shall NTS be written (Mar 93) + In 1992, there was much discussion, in which language an NTS should be + implemented (candidates were LISP, C, and WEB). This has settled in March + 1993 (to PASCAL-WEB), because of the acceptance of the + idea that rather than wait for an ``all-singing, all dancing'' NTS, the + group should develop, in a stepwise manner, small but significant + enhancements to TeX. This implies that the enhancements are implemented as + change files in WEB. + +3.3. The TeX language (Oct/Nov 93) + The TeX language is a simple language in the sense, that it contains only + few concepts. It belongs to the Lisp family. In particular, it's a + list-based macro language with late binding. Actually, that's all one + needs to say to characterize it. + Its data constructs are simpler than in Common Lisp: `token list' is the + only first order type. Glue, boxes, numbers, etc., are engine + concepts; instances of them are described by token lists. + Its lexical analzsis is simpler than CL: One cannot program + it. One can only configure it. + Its control constructs are simpler than in CL: Only macros, no + functions. And the macros are only simple ones, one can't compute + in them. + +3.4. The TeX engine (Oct/Nov 93) + The TeX engine lies below the TeX language. Glue, boxes, numbers, etc. + belong to the TeX engine. The registers of the engine can be changed + by TeX's primitives. However, the latter seem to be quite unregular and + baroque. + +3.5. Extensions and Enhancements (Nov 94) + `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. + +4. Deviations + +4.0. General + (empty) + +4.1. Automated Kerning (Oct 92) + Kindersley's "optical kerning": for the purposes of + kerning, each character is replaced by a circle centred on the centre of + gravity of that character; the radius of the circle is determined by the + fourth moment of the character (that is, the fourth root of the sum over + all black pixels of the fourth power of their distance from the centre). On + the UKTUG trip to Kindersley's studio, I tried to extract the reason why + the fourth, as opposed to third or fifth or whatever, moment is used; the + reason is apparently that it "looks right". + + We can construct elaborate schemes for kerning (Kindersley's fourth + moments, FontStudio's (convex?) envelopes, Calamus' eight widths, etc), but + the proof of the typographical pudding is in the eating of the resulting + words, so to speak. + +4.2 About Lout (June 1993) + In June 1993, the new system Basser Lout caused several questions and + suggestions on this list. The following is taken from a short review + of Lout by Bernd Raichle: + + `Lout' is a (yet another) document formatting system, released under + the terms of the GNU General Public License and available on some ftp + servers. + + IMHO it's more like a `troff' (with a better input language and some + newer concepts) than a `TeX'. + + A few citations from the documentation of lout: + + Lout is a high-level language for document formatting, designed and + implemented by the author. The implementation, known as Basser + Lout, is a fully operational production version written in C for the + Unix operating system, which translates Lout source code into + PostScript, a device-independent graphics rendering language + accepted by many high-resolution output devices, including most + laser printers. + [...] + When expert users can implement such applications quickly, + non-experts benefit. Although Lout itself provides only a small + kernel of carefully chosen primitives, + + Lout has 23 primitive operators... missing, for example, the simplest + arithmetical operators (there is only the operator "@Next" which + increases a number by one). + + packages written in Lout and distributed with Basser Lout provide an + unprecedented array of advanced features in a form accessible to + non-expert users. The features include rotation and scaling, fonts, + + These features are mostly based on the output language... Postscript + (if you are looking inside a Lout package, you find large portions of + embedded Postscript code). + + paragraph and page breaking, + + TeX does a better job for these two items, because Lout is missing + most of TeX's paragraph/page breaking parameters. (Note: Lout uses + TeX's hyphenation algorithm and the hyphenation patterns.) + + displays and lists, floating figures and tables, footnotes, chapters + and sections (automatically numbered), running page headers and + footers, odd-even page layouts, automatically generated tables of + contents, sorted indexes and reference lists, bibliographic and + other databases (including databases of formats for printing + references), equations, tables, diagrams, formatting of Pascal + programs, and automatically maintained cross references. + + TeX's math setting abilities are better. Lout uses a package named + `eq' derived from the `eqn' preprocessor used with `troff'. And there + are other packages named `tab' (for tabulars) and `fig' (drawing + figures). + + [...] + Lout is organized around four key concepts -- objects, definitions, + galleys, and cross references -- [...] + + The concept of `galleys' and the "expansion" of recursive defintions + are IMHO the only new concept in Lout: + + `galleys' are a way to describe a page, dividing it in certain regions + which can be filled from different sources (e.g. a footnote galley is + filled with footnote text, etc.). + + Recursive definitions are very simple, e.g. + def @Leaders { .. @Leaders } + defines the command (Lout calls it `object') to "expand" to a `..' and + if there is place for another "expansion" it is called again. + + For example + \hbox to 4in{Chapter 7 \dotfill 53} + is in Lout + 4i @Wide { Chapter 7 @Leaders 53 } + + With this recursive definitions, a whole document is defined as a + @PageList consisting of a @Page and a @PageList with an incremented + @PageNum. A @Page is defined as a set of `galleys' (header, text + body, footnotes, footer), which are also defined as a list of + text/footnotes/... and so on. + + Perhaps others can add more impressions, mine are based on the + documentation coming with the Lout package and some tests done in + 1-2 hours. + +5. Proposed changes to METAFONT + +5.O. General + Most of the General points in the discussion of TeX also apply to METAFONT. + +5.1. Writing to auxiliary files + METAFONT should be able to write to auxiliary files. Desparately needed + for packages which allow to draw figures in METAFONT and label them in TeX + (BoF session at EuroTeX '92, Prague). + + +6. Proposed changes to the tfm file format + +6.1. Vertical kerning (Jun 92) + This may sound exotic to you, but the AFM format can do + it. And I desperately need it for non-Latin alphabets (everytime I need + a character in a ligature raised or lowered, I have to reserve a position + in the font for it). + +6.2. Cross-font ligatures (Jun 92) + Ligatures pointing to other fonts!! Yes, imagine for example that your + 256 chars are full, you could still access characters by ligatures...but + they have to be in the same font. + +7. Proposed changes to the dvi file format + +7.0. General + A longer discussion about colour inclusion into the dvi-file occured in + Oct/Nov 93. The outcome was, that high-quality colour handling is a difficult + and device dependent task, better left to the printer driver. Colour can be + handled by the \special command which is sent directly to the driver. + + On comp.text.tex I saw a remark, that specials may occur on places in the + dvi-file, where TeX can't put them. Maybe eTeX should take care of this + point. + +7.1. Horizontal and Vertical Mirroring (Nov 94) + Allow a glyph to be mirrored in a vertical axis, placed centrally; + mirrored in a horizontal axis, placed at half the x(?)-height. + + It was noted, that the specification of the axes might cause problems. + It was also noted, that several drivers understand specials for the + requested action. + +7.2. Rotation of a glphy by 180 degrees (Nov 94) + 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. + + It was noted, that this is fine, but rotation by 90 degrees cannot be + device independent, because there are printers with rectangular (non-square) + pixels. + +8. Additions to the TeX kit + +8.0. General + The TeX kit, meaning the bundle of programmes building up a complete TeX + installation, contains besides the major programmes TeX and METAFONT + additional programmes, traditionally divided into several groups: + + a) TeXware: dvitype, tftopl, pltotf, pooltype, pktype, patgen, vftovp, + vptovf, (outdated: pxtopk, pktopx) + b) MFware: mft, gftodvi, gftopk, gftype, (outdated: gftopxl) + c) webware: weave, tangle + + And, of course, drivers for the screens and printers. + + Other utility programmes more loosely associated with TeX are indexers + (makeindex, idxtex, glotex, ...) and bibliography tools (bibtex, + bibclean, ...). Makeindex and Bibtex are standard tools, because they + are described in the LaTeX manuals. + + Another group includes drawing programmes (TeXCAD, xfig, gnuplot, ...) to + create graphics to be imported to TeX documents and graphics converters + (ghostscript, xv, bmt2font, ...). + +8.1. dvicopy + Written in WEB by Peter Breitenlohner + Available from CTAN + Resolves all references to virtual fonts in a dvi file. Can be used to + create a dvi file without virtual fonts (e.g. for drivers which cannot + handle vf's). + +8.2. dv2dp and dp2dv + Written in C by Geoffrey Tobin + Available on request from the author + dv2dp makes a human readable file from a dvi file. The companion + programme dp2dv makes a dvi file frome a dvi property list file. + It allows you to change dvi files with a text editor. + +8.3. gftotxt + Written in C by Yannis Haralambous + Available ? + Extracts a certain kind of specials from the gf file into a text file. + Workaround for the famous non-ability of METAFONT to write auxiliary + files. + +8.4. qdtexvpl + Written by Eberhard Mattes + Available from the CTAN archives + Generates a virtual font from TeX macros. qd = quick and dirty. + +8.5. fontinst + Written in TeX by Alan Jeffrey + Available form CTAN + Makes virtual fonts from afm files (PostScript fonts). Used by the LaTeX + team to create virtual fonts and fd files for LaTeX2e. + +8.6. afmtotfm + Written in C by Thomas Rokicki + Available from CTAN (part of dvips distribution) + Makes tfm files from afm files. + +8.7. dvipaste + Part of LAMSTeX (Michael Spivak) + Allows to paste a dvi-file into another one. + +8.8. METAPOST + Written in Web by John Hobby + Now freely available from the CTAN + A tool to build graphics to be included in TeX documents, uses a METAFONT + style language. + +8.9. Tie + Written by Klaus Gunthermann + Available from CTAN + Allows to process multiple change files to a given Web source. A tool + of this kind is needed to build any eTeX distribution, since one has + tex.web, etex.ch, tex.ch-system, and etex.ch-system files to deal with. + +8.10. dvi2dvi + Available from CTAN + Postprocessor for dvi files, allowing e.g. 2-up or 4-up layout of full + pages. + +9. Existing extensions to TeX + +9.0 General + Here I include short description of existing extensions to TeX. This section + does not include commercial TeX implementations because of lack of solid + enough information on them. It also does not yet include ETeX, NTS, nor + Omega. + +9.1. TeX-XeT (Don Knuth and Pierre MacKay) + CTAN: tex-archive/systems/knuth + Adds new primitives \beginR, \endR, \beginL, and \endL for right to left + typesetting. Despite their names, the new primitives are insensitive to + TeX's grouping mechanism. Outputs a special file in dvi-ivd format, which + need be resolved by another programme or requires special drivers. + +9.2. TeX--XeT (Peter Breitenlohner) + Available from CTAN tex-archive/systems/knuth/tex--xet + Implements the same primitives as TeX-XeT, but outputs a normal dvi file. + Passes the trip test (as far as I know). + +9.3. MLTeX (Michael Ferguson) + Available from aldebaran.ee.mcgill.ca in pub/mltex + Adds a primitive \charsubdef, which allows the following: input of 8-bit + characters, participation of accented characters not present in the output + encoding in hyphenation, ligatures and kerning with accented letters. + Especially popular in francophone countries. + emTeX supports MLTeX via the /ml option. + +9.4. SiSiSi (Wilhelm Barth, Heinrich Nirschl, Heini Hofstaedter und Harald + Mueller) + Available from CTAN: tex-archive/systems/vms (sic!) + Implements another hyphenation algorithm (the name means SIchere + SInnentsprechende SIlbentrennung, which is translated `secure sensitive + hyphenation') specific to the german language (with Haupt- und + Nebentrennstellen). Fails the trip test, therefore not a legitimate TeX. + In use at TU Wien (Austria). + +9.5. Japanese TeX + [in preparation] + +The End. -- cgit v1.2.3