Questions tagged [primitives]
{plain-tex} commands used for macro {programming}.
57
questions
18
votes
1answer
1k views
Difference between \hfil and \hfill
I am trying to understand the difference between \hfil and \hfill. I always thought that these commands were roughly equivalent except that \hfill was "stronger" than \hfil. As a result, I thought ...
7
votes
1answer
1k views
what is \kern good for
What is \kern instruction good for and how is it defined?
I cannot find it in Knuth's book TeXbook.
5
votes
1answer
85 views
Get correct results for overwritten font identifier
How can I get a correct font identifier with \showthe and \the after it is overwritten? The MWE is below (Same result with all of Knuth TeX, pdfTeX, XeTeX, (e-)pTeX, (e-)upTeX and Aleph. Only LuaTeX ...
4
votes
3answers
85 views
Overriding control sequences for accessing TeX's integer-/dimension-/glue-/..-parameters
In TeX there are a lot of parameters which you can adjust for changing the behavior of TeX.
Example 1:
By assigning \baselineskip=... you change distance between lines.
Why TeX's breaking-paragraphs-...
1
vote
1answer
145 views
What is “# Notation”? How does the # syntax work?
Closely Related: How to implement \expandbefore, similarly to \expandafter?
In the related question, a reference is made to the "# Notation". How does the syntax work?
From an answer on the other ...
3
votes
1answer
409 views
Different file opened by \openin (was: between 2017 and 2018)
Short version:
It seems that some trivial behavior of file opening (\openin) changed between TeX Live 2017 and 2018 differs between environment. Only Overleaf one behaves differently. I did not see ...
18
votes
2answers
866 views
Is there a list of expandable TeX primitives? LaTeX? e-TeX? others?
According to Christian Hupfer's comment I understood that calculations are possible in a keyval list when the macro is expandable. The macro \numexpr being expandable, calculations are possible.
...
1
vote
1answer
157 views
TeX macro/primitive vs Plain TeX macro
I know there are TeX primitives and Plain TeX macros created (directly/indirectly) by TeX primitives. My question is are there TeX macro?
E. g. I can use \break in pdfTeX without defining it and \...
5
votes
1answer
128 views
\string-primitive works in unexpected ways in LuaTeX — Where can I find exact documentation of the \string-primitive in LuaTeX?
Where can I find exact documentation of the \string-primitive in LuaTeX?
I ask this question because I encounter some unexpected (at least by me) behavior when compiling the example below with LuaTeX....
1
vote
1answer
210 views
Changing text in Console output
I am finding that I am writing more and more packages/commands for other people these days and have started writing some nice default utility commands to use. However, there is always the concern for ...
3
votes
1answer
265 views
Error of \begin{problem} ended by \end{problem}… huh?
So, I know if I get a mismatch error like error: \begin{problem} ended by \end{document}, that means I have mismatched number of \begin and \end commands. But here, I am getting the following error:
!...
1
vote
1answer
76 views
Swap many pair of command names in a row
I've learnt from this post how to swap two commands using the let primitive:
\let\temp\first
\let\first\second
\let\second\temp
\let\temp\undefined
Now, in order not to flood my preamble with this ...
0
votes
0answers
170 views
Conditional to execute alternative code when error detected
I would like to be able to build a conditional to execute one set of code if the conditional would compile, versus another if the code would generate an error. Take the following code block which ...
6
votes
2answers
551 views
hide/show complete row of tabular
I need to toggle on/off full rows of a tabular via changing my preamble. My workflow only permits me to alter the first cell of each table in order to make it toggleable.
My idea was to use the ...
15
votes
2answers
1k views
What's the difference between \hfil and \hskip0cm plus 1fil?
What's the difference between \hfil and \hskip0cm plus 1fil? In both cases, a glue token is created that skips by zero, but with 1fil of stretchability. If you use \hbox spread 4cm{\hfil test \...
3
votes
1answer
79 views
How to test if a macro is being expanded between \csname … \endcsname, in (e-)upTeX?
pdfTeX added some new primitives, based on e-TeX, including \ifincsname. When this primitive is being expanded between a pair of \csname ... \endcsname, the result of expansion will be true, otherwise ...
3
votes
1answer
17k views
How to fix the Underfull \vbox badness has occurred while \output is active on my memoir chapter style?
After some hours studying the warning Underfull \vbox (badness 2573) has occurred while \output is active on the question how to suppress "Underfull \vbox (badness 10000) ... while \output is ...
16
votes
2answers
737 views
Documentation of \mathop
The Dirac delta distribution is ubiquitous in physics. Since it is a special object I wanted to give it some extra spacing by using \mathop. I know that single letters inside \mathop are centred ...
9
votes
2answers
9k views
Practical consequences of using \over vs. \frac?
This question explains the difference between \over and \frac and it seems as though the most experienced members unanimously agree that \over is inferior (if not something to be outright regretted); ...
3
votes
2answers
595 views
List of Plain TeX macros [duplicate]
Where can I get a list of all Plain TeX macros. In the TeXbook, it is said that Plain TeX adds about 600 macros (to the ~300 TeX primitives). Where are they listed (with their documentation)?
9
votes
3answers
1k views
How to use @ifstar with arguments
I want to use @ifstar to define a command, whose non-star version stores a value in a variable and whose star version reads the value from the variable. I tried the following. It doesn't produce an ...
1
vote
5answers
285 views
Error trying to use \edef
Feel free to skip past this explanation to the code below. My issue is trying to get \Q@Selection to work with edef.
I have a macro that uses a for loop to assign some dynamic macros that I am toying ...
0
votes
2answers
109 views
How to detect the range of possible character codes?
Please forgive me if this question is too basic for this forum.
I came into touch with TeX three weeks ago.
I learned that there are different TeX engines.
E.g., there are TeX, eTeX, pdfTeX, pdfeTeX, ...
0
votes
1answer
153 views
How can I redefine \\ (\tabularcr) such that a space character afterward is ignored?
Here I append code to \\ that looks ahead to see whether the \end in \end{tabular} is up next to bat. This code is hidden within a \noalign. The \\ has code that looks for a star and then a [ before ...
1
vote
1answer
46 views
Is there a way to have \show not behave like an error? [duplicate]
Everybody loves the \show tex primitive.
Sadly it so happens that whenever I \show something the execution/compilation which I call using pdftex -halt-on-error also stops, which was quite supprising ...
17
votes
3answers
840 views
The "^'' glyph in the TeXBook
TeX, plain TeX, within the source of the Texbook of Don Knuth, there is use of ^ in different command sequences, and in text bites.
Is there a special meaning to ^ in TeX primitives, in plain TeX, ...
7
votes
1answer
219 views
computing md5sum of file content in XeTeX
PdfTeX has \pdfmdfivesum{...} and \pdfmdfivesum file {...} for inline text and external file content, respectively.
On the other hand, XeTeX seems to provide only \mdfivesum. Is there a means to ...
1
vote
0answers
187 views
Where should I specify pdftex primitives? [duplicate]
I would like to suppress this type of warning by pdftex:
PDF inclusion: multiple PDFs with page group
So one solution proposed here is to use this primitive:
\pdfsuppresswarningpagegroup=1
Where ...
1
vote
0answers
67 views
Append code to the \directlua primitive
LuaTeX provides the primitive \directlua, which is described in detail in section 1.6.1 of the LuaTeX reference manual. Basically, this primitive runs Lua code. Its syntax is:
\directlua āØgeneral ...
27
votes
2answers
2k views
What is a primitive, a macro, and how do they compare?
The title pretty much says it all. If it helps, I found myself asking this question when reading this post about \par vs. \\.
12
votes
1answer
1k views
Can one safely redefine \jobname?
I want to access labels from an external document -- in general this is not a problem with the xr package. But in this case both documents are compiled on sharelatex, and there \jobname is always set ...
9
votes
1answer
266 views
Somewhat versatile usage of \@gobble and \@firstofone found in several macros
I was doing search about my question (see here for more detail) and found a thread commath and \ifinner. In the thread, there is a macro named \spx , the definition and usage of which are extracted ...
14
votes
1answer
912 views
Prevent scaling of printout of PDF without using hyperref
pdftex produces PDF. We need a viewer to view the PDF and print it. Some of those viewers tend to scale the printout:Ā the letters shrink. This is a bug especially of the Adobe Reader and explained ...
23
votes
1answer
3k views
What does \/ do?
I've seen this in some tex file where a word is set in italics, but its ending is in regular font. Trying it out I don't see it making any difference, so I must be missing something. What does the \/ ...
5
votes
2answers
268 views
Trying to understand \def\def@ sintax primitives
I am trying to understand this syntax of primitive \def
\DeclareOption{man}{%
\def\def@man{\@manmode}
}
Why this primitive nesting? And I do not get to understand why there is two \def sentences ...
5
votes
2answers
265 views
New primitives and grammar for replacing horrible \expandafter
Time and time when I am trying to read or write some macros, I'm always frustrated by lots of \expandafters inside them. Why don't we add some new primitives and grammar into TeX engines to make ...
10
votes
1answer
257 views
List of all control sequences let to primitives in common formats
I would like to know a list of all control sequences which are let equal to primitives in common formats. For plain TeX for instance, we would get the list
\endgraf % = \par
\endline % = \cr
\repeat ...
14
votes
3answers
3k views
Change \the\year
Is it possible to make LaTeX believe that the current year is 2012, so that \the\year prints 2012?
\documentclass{article}
\begin{document}
% What to do so that the following prints 2012?
\the\...
3
votes
1answer
176 views
Can I use a TeX primitive in a “before” and “after” macro? (and how?)
The Question
Can I use a TeX primitive in a "before" and "after" macro? (and how?)
There are two questions that I found useful and related to my question, which sent me in the right direction: how ...
29
votes
1answer
366 views
Which primitives does LaTeX2e rename/move?
TeX's primitives can be renamed by macro formats/packages: this allows new/altered features or behaviours. Usually this is done such that the originals are still available ('renamed'): certainly ...
13
votes
1answer
283 views
Which primitives does ConTeXt rename/move?
TeX's primitives can be renamed by macro formats/packages: this allows new/altered features or behaviours. Usually this is done such that the originals are still available ('renamed'): certainly ...
8
votes
1answer
622 views
Why should some TeX primitives never be set directly in LaTeX?
In an earlier question More economic and robust command for abstract at the beginning of chapters, David Carlisle told that one should never use directly some TeX primitives. How can I distinguish ...
8
votes
1answer
296 views
How can \ifx\\\\ be false?
It appears that I have a case where \ifx\\#2\\ is false, even though #2 is empty.
Here is the relevant excerpt from the log file, with \tracingcommands and \tracingmacros turned on:
\lastpageref -&...
29
votes
1answer
2k views
Using elastic lengths — when do they work?
I was wondering why elastic lengths like \fill seem to work only under certain conditions.
For instance if I write
A \hspace{\fill} B
I get A left aligned, B right aligned as wanted. If however I ...
4
votes
2answers
410 views
ConTeXt doesn't implement some Knuth TeX primitives?
I try to use new TeX format ConTeXt, but I find that some TeX primitives don't act any more. How sad I am when I find that.
An simple example is that in plain TeX, we can set the spaces between ...
6
votes
1answer
388 views
How to emulate \pdfstartlink and \pdfendlink with xetex?
In my ocgx package, I would use the new ocg-p package instead of the ocg package. With pdflatex or lualatex, all is good. But with xelatex, I obviously can't use \pdfstartlink and \pdfendlink (these ...
12
votes
3answers
1k views
A command to replace \middle| when it's missing?
I'm using this LaTeX plugin for a Wiki (Confluence, blech), and it doesn't support the \middle| command. I'm guessing it doesn't have eTex primitives or some such backwardness. Anyway, I guess I can ...
59
votes
3answers
79k views
how to suppress “Underfull \vbox (badness 10000) … while \output is active”?
when using an inflexible document class, one is often faced
with the warning
Underfull \vbox (badness 10000) has occurred while \output is active []
on pages that contain no display math.
in ...
12
votes
2answers
3k views
Is it safe to temporarily redefine \and, \or, and \not?
I'm writing lots of logic expressions in LaTeX and I'd much rather write $p \and \not q \or r$ than $p \land \lnot q \lor r$. I was thinking of doing something like this:
\newenvironment{logic}{%
\...
3
votes
1answer
505 views
Converting command to result
Consider this example:
\documentclass{article}
\newcommand{\foo}{}
\newcommand{\currentbar}{\thebar}
\newcounter{bar}
\setcounter{bar}{0}
\makeatletter
\newenvironment{baz}{\addtocounter{bar}{1}}{\...
