{tex-core} is for questions that are independent of formats and macro packages. Such questions usually relate to low-level TeX programming or the behaviour of TeX at an underlying level. Note that even Plain TeX is a format in itself; for questions about it, use {plain-tex}.

learn more… | top users | synonyms (1)

11
votes
2answers
487 views

Difference between unrestricted and internal vertical mode

At any point in the processing of a document, TeX can be in one of seven modes: no mode (only in \write and similar commands, I think), math mode ($...$), display math mode ($$...$$), restricted ...
11
votes
1answer
97 views

\toks register expansion issue - or is it?

I am trying to assemble a table that occurs multiple times throughout a document. It always consists of some fixed columns, followed by a set of columns that appear in one table but are not needed in ...
11
votes
2answers
140 views

increase \hyphenation{word1 word-2…} capacity

We use LaTeX to typeset a large collection of books with many proper names. We use the \hyphenation{word1 word-2...} command to specify words that should not be hyphenated and to suggest hyphenation ...
11
votes
1answer
331 views

TeX capacity exceeded, sorry [semantic nest size=500]

Reading through tex.web, I note that there is a difference between grouping levels and semantic nesting (i.e., the nesting of math, horizontal, and vertical modes). I can think of commands which ...
11
votes
1answer
396 views

Interwoven alignment preambles are not allowed - what exactly does this mean?

I admit that this post is purely idle curiosity. But I recently stumbled upon a little factoid saying that the TeX error "Interwoven alignment preambles are not allowed" has the following explanation ...
11
votes
2answers
196 views

What combinations of mode and \currentgrouptype exist?

I am trying to predict in any given situation what TeX does if a closing brace reaches its stomach (apart from reverting local assignments). For instance, \vbox{\tracingall H} shows that if it is in ...
11
votes
2answers
152 views

Is there any reason to define a zero-argument macro using a starred defining command?

Is there any reason to define a 0-argument (read: zero-argument) macro with a starred command (\newcommand* instead of \newcommand or \DeclareRobustCommand* instead of \DeclareRobustCommand)? After ...
11
votes
1answer
147 views

How many different concepts of “token equivalence” are there in TeX?

I was living in the delusion that the "token equality" tested by \ifx was the only thing you need to remember about this subject, but this week I learned otherwise (thanks to David Carlisle). Now ...
11
votes
2answers
84 views

split off function for variable as separator

How/Possible to change this implementation of \xSplit so that the separator is a variable filled in at the time of definition (\edef somehow?) or at the actual use of the command?? %based on the ...
11
votes
1answer
100 views

Measure total glue in a box

Someone gives me a box, and my goal is to know as much as possible about the amount of glue inside that box. I can assume that the box is not huge, but it may contain arbitrary stuff (so I cannot ...
10
votes
3answers
400 views

Why is tex designed to render spaces around brackets?

When I wrote following lines: \section{Introduction}{ Content in introduction ... } Unwanted space comes before Content as warned. I understand it's due to some technical decision in tex. But I ...
10
votes
4answers
519 views

Extract first, last and rest of tokens

This question is related to Extract first & last characters of macro argument?. It seems that if, besides getting first and last tokens, one wants to accumulate the rest of the tokens, the ...
10
votes
3answers
982 views

Check for empty macro argument

There is a description on how to check whether the argument of a macro is empty in What does \ifx\\#1\\ stand for? Unfortunately, I can't get any of the examples there to work. Among others, I have ...
10
votes
2answers
670 views

Where to find official (!) and extended documentation for tex/latex's commandline options (especially -interaction modes)?

Today I tried to learn more about the several interaction modes for tex/latex/pdflatex etc. The manpages turned out to be not very helpful: $ man tex ... -interaction mode Sets the ...
10
votes
2answers
273 views

All (La)TeX warnings and errors

For testing purposes, I am looking for a comprehensive list of all errors and warnings that TeX, and LaTeX can output. I don't mean errors and warnings produced by all packages, as this would give an ...
10
votes
4answers
154 views

# in conditionals in alignment tabs?

I am looking for ideas how to make TeX understand that when # appears both in the if-else and in the else-fi part of a conditional in an alignment tab, in the end there will never be more than one # ...
10
votes
2answers
99 views

\csname not working as expected

The following code prints ==atname== \def\atname{atname} \def\xxx{name} \def\at{at} ==\csname\at\xxx\endcsname== \bye but this does not: \def\@name{atname} \def\xxx{name} \def\at{@} ...
10
votes
2answers
1k views

How to include eps files in Plain TeX? [duplicate]

The title stands for itself. If it is not possible, how does LaTeX import an EPS file using \includegraphics?
10
votes
2answers
1k views

What is the plain TeX equivalent of \settowidth?

The \settowidth command, which sets a width equal to the width of some text, is described at Get width of a given text as length and How to set the width of the label of a description to the width of ...
10
votes
2answers
196 views

Why is \newcount declared \outer?

I'm a user primarily of Plain TeX. Lately I get annoyed about the \outer nature of \newcount, especially when I write macros which require temporary internal variables, variables which really need not ...
10
votes
3answers
443 views

Making register declarations local, Undefining a register (count, toks, etc.)

Is it possible to make \newcount, \newtoks, etc. respect grouping, so that, e.g., \newcount\temp\temp=2{\newcount\temp\temp=1}\showthe\temp gives 2 (instead of 0)? Relatedly, is it possible to ...
10
votes
3answers
1k views

How do I get the width of \hfill?

In my LaTeX document, I have a first line with a given spacing obtained using \hfill, then a paragraph, and then a third line in which I would like to use the same spacing as in the first line. The ...
10
votes
2answers
328 views

Catcode of \endlinechar when its charcode is less than 1

When \endlinechar is less than 1, how do we access its catcode? The following gives the error shown below: ! Bad character code (-1). l.34 ...ndlinechar\string=\the\catcode\endlinechar ...
10
votes
5answers
551 views

What is the minimum TeX one can use to put together a mathematical document?

Being a mathematician, I use LaTeX a lot for writing. However, I am interested (mildly) in working with TeX instead, even if only for keeping my own notes. What is the minimum amount of TeX do I need ...
10
votes
2answers
324 views

TikZ/TeX: Minimum line width/maximum resolution

I would like to employ TikZ for some constructive work, namely, programming a FabLab laser cutter. This nifty device gets a 2d drawing (as PDF) and cuts along all hairlines in the PDF. A harline is ...
10
votes
2answers
207 views

Execute non-expandable code inside a tabular environment

As there is no Expandable version of \InputIfFileExists or \IfFileExists, the question arises whether it is possible to execute non-expandable code in a tabular environment after all: File main.tex: ...
10
votes
1answer
161 views

What is the difference between a typesetting language and a markup language

I remember, I read some article in a technical journal where the author drew the attention on the reader on a lot of people confusing typesetting languages and markup languages. How can I surely tell ...
10
votes
1answer
123 views

Interactively look up macro definitions

In a TeX document, the primitive command \show will print out the current definition of a macro one level deep (it won't (and can't?) reduce to primitives). This comes with the restriction of actually ...
10
votes
2answers
162 views

How can the contents of a TeX \mark be viewed?

The purpose of marks in TeX is to generate running heads. One inserts material to a mark, simply by: \mark{A running head} If we write a short TeX program, we can see that the contents of \mark ...
10
votes
4answers
1k views

Generalize \@ifnextchar to consider more than one character.

I am looking for a clever way to write a switch statement based on the next input characters, ideally, one could write: \@switchnextchars \@case{abc}{\typeout{You gave me an abc}}% ...
10
votes
3answers
978 views

`\write` non-printable ASCII characters to a file

\immediate\write\SomeStream{x} writes x to the file open in \SomeStream. I would like to write non-printable ASCII characters, such as ``, to a file. My naive guess is \begingroup %To keep ...
10
votes
1answer
147 views

TeX doesn't recognize built-in control sequences?

I'm trying to learn to build things from the ground-up with TeX (not LaTeX---I've used LaTeX before, so I know how easy a solution "\usepackage{amsthm}+\begin{theorem}" is) and I'm trying to build my ...
10
votes
1answer
438 views

Macro delimiter

I'd like to have a macro to split up another macro content, with field separator being a space. So: \def\mytext{foo bar} \def\secondof#1 #2{#2} \secondof\mytext What? What do you mean: "runaway ...
10
votes
2answers
100 views

\prevdepth and \noalign

In The TeXBook it says The value of \prevdepth at the time of the \halign is used at the beginning of the internal vertical list, and the final value of \prevdepth is carried to the enclosing ...
10
votes
2answers
968 views

Minimum length of last line of a paragraph

There is a more or less equivalent question to this: Ensure minimal length of last line, but I absolutely need a TeX solution. I more or less stumbled upon the problem mentioned in the discussion of ...
10
votes
1answer
278 views

What documentation thoroughly explains how to use TeX conditionals?

I have a document which needs a large variety of plain TeX conditionals, e.g.: IF #1 >= 1 AND #2 >= 10 IF #1 != “tree” OR #2 == “mountain” IF 10 > #1 > 2 I have found limited ...
10
votes
2answers
587 views

How to use tex -ini, tex -fmt, initex and fmtutil?

What are the roles of each of these commands? What is the good command to create a new format ?
10
votes
1answer
207 views

Macro parameter delimited by more than one delimiter

TeX user can simply create the macro with a parameter delimited by an arbitrary sequence of tokens. For example \def\macro #1delimiter{...#1...} Is it possible to create a macro with a parameter ...
10
votes
1answer
137 views

Emulate TeX's grouping

In TeX, various kinds of groups must match properly, for instance, the following is wrong: $ \begingroup $ \endgroup I would like macros which allow such mismatched grouping. They would keep ...
10
votes
1answer
238 views

Making a character active vs assigning it a specific catcode

My query arises from my answer to Tab not as extra alignment tab and Andrey's rather nicer version. The question at hand involved making the TAB character usable for aligning tables. I assigned it to ...
10
votes
1answer
166 views

vbox disappearing inside hbox

I don't understand why a vbox disappears when it's surrounded by two \hss, for instance in: \hbox to 0pt{\hss abc\hss} \hbox to 0pt{\hss\vtop{def}\hss}% doesn't work \hbox to 0pt{\vtop{ghi}\hss}% ...
10
votes
1answer
221 views

How to install or replace fonts in old TeX files?

I got interested in a research paper from 1991, which I cannot get an electronic online version of. The author was kind enough to send me his tex sources, but is himself unable to produce a pdf file ...
10
votes
1answer
1k views

Newline/linebreak in \message

I want to prompt some messages to my console. I used \message{Hi out there!} Now i want some more Text but with an linebreak. \message{Hello World %some line break here Salut monde } Well i ...
10
votes
2answers
737 views

Reading the contents of a box

Is it possible to take a box and retrieve the following information from it: A list of all "top level" internal boxes; All intervening space (kerns and glue: did I forget another type of space?)? ...
10
votes
1answer
835 views

Trapping LaTeX error/warning

Is there a way to trap an error/warning in LaTeX during compile time? I'm thinking of something similar to the VB script On Error Goto <blah>, but this time for LaTeX in something like ...
10
votes
2answers
716 views

Do XeTeX and LuaTeX always use Unicode?

I am writing some functions to manipulate strings. A typical way to produce a character with a given character code is the \lowercase primitive. The following code produces a character with code 234, ...
10
votes
1answer
266 views

How can I make a PDF of the source of pdftex?

I got the files tex.web and pdftex.web from the texlive svn repo. I ran weave tex.web pdftex tex.tex which produced a file tex.pdf with a nicely typeset, cross-referenced listing of the WEB source ...
10
votes
2answers
353 views

Starting point for getting more familiar with TeX/LaTex etc

Background: I've been using what I would call LaTex for ~4 yrs to typeset assignments, reports, essays and tutorial notes. I have been using "TexShop" (for Macs) - mostly because it was simple when I ...
10
votes
1answer
93 views

assign penalty to one discretionary (not all paragraph)

For a quite complex problem that would be too long to describe, I need to set different penalties for different discretionaries in the same paragraphe. It doesn't seem to be possible with pdfTeX (and ...
9
votes
6answers
1k views

Function like macro?

If you have programmed in a high level programming language, you must be familiar with the concept of functions, subroutines which return a value. For example, if you write in C, you can write a ...