{expansion} is about expanding tokens, including the manipulation of expansion order and the suppressing of expansion.

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24
votes
7answers
2k views

Are there purely expandable variants of \MakeUppercase?

\MakeUppercase and \uppercase use TeX's uccode, and they are not purely expandable. Say, \edef\temp{\MakeUppercase{abc}} will fail. Sometimes purely expandable macros are very useful. They are ...
11
votes
1answer
130 views

Why this output using \string on the empty csname

How does this exactly work? \expandafter\string\csname\endcsname I don't know what I would expect to come from there, but definitely not \csname\endcsname_ where _ is a space. I thought ...
3
votes
1answer
31 views

Problem with expansion of \@ifnextchar inside tabular environment

I'd like to define a macro that expands to \hline and \cline inside the tabular environment depending on the next character: \documentclass{standalone} \makeatletter ...
3
votes
2answers
48 views

Expand \def value from optional default argument? - Bug in \oldacronym (glossaries v4.02) - first use not respected and funny effects?

Edit: Bug only in glossaries v4.02. -> Update! \edef\args{[#4]{#1}{#2}{#3}}% \expandafter\newacronym\args% may be a way to expand unexpaned args. Is there a bug in the glossaries ...
2
votes
1answer
63 views

Define an expandable function for comparing a token list to a string in LaTeX3

In LaTeX3, I could define a function for comparing a token list to a string \cs_generate_variant:Nn \tl_if_eq:nnTF { V } \cs_new_nopar:Npn \module_compare:n #1 { \tl_if_eq:VnTF \g_some_tl { #1 ...
7
votes
2answers
75 views

Appending active and expansion sensitive characters to a macro

This question comes up pretty often when people want to build tables with empty columns or similarly building up some active characters inside a macro hoping to expand them at the right time right ...
1
vote
1answer
33 views

Command containing babel shorthand not expanding [duplicate]

Greetings to the distinguished gathering of TeXperts! My problem is: if a macro is defined with a babel shorthand containing the quote mark (") as an active character, it does not expand when ...
6
votes
1answer
57 views

Delimited \def's and expansion

I try to understand how work the macro named \separator in MWE . \documentclass[]{article} \def\separator#1\separator#2{% \unexpanded{#1}% \ifx*#2% \else , \expandafter\separator\expandafter#2% \fi ...
8
votes
2answers
238 views

Could someone explain the tokenization process that's leading the whitespace creeping in here?

Here's a MWE that creates spurious whitespace: \documentclass{article} \usepackage[T1]{fontenc} \usepackage{lmodern} \newcommand\aetest[2][\relax]{%% \def\aejunk{<#2>}%% \ifx\relax#1 ...
4
votes
2answers
73 views

loop in tabular that uses \the\count to access current line number

I would like to generate an autmatic table using loop. As suggested here before, it is best to first generate the lines in a toks and then pass them to tabular. However, I have problems with accessing ...
10
votes
3answers
167 views

Expandably change letter case and use inside \csname, without a package

I want to change the letter-case of a single character argument, and use that changed letter inside a \csname. And I want to do it without an additional package. For example, I want to pass a macro ...
4
votes
2answers
142 views

How to pass parameters to Sage from Sagetex?

I haven't found a way to pass parameters to a sagesilent environment, so I wonder if it's possible. My final purpose is to combine sagetex with probsoln. The package probsoln lets you manage a problem ...
6
votes
2answers
126 views

TeX/LaTeX: Macro for getting a length as number

I would like to write a macro getlengthin to get a length or dimen as floating point number in a specified unit. Here is what I have created so far: \documentclass{article} ...
6
votes
4answers
71 views

How to expand a macro into viewport= arguments(includegraphics)

How do I properly expand a macro \myviewport so that it is parsed as the viewport=0pt 10pt 100pt 200pt argument of \includegraphics[clip, \myviewport]{somepdf.pdf}? \documentclass{article} ...
5
votes
2answers
91 views

Inserting Macros in argument of \sindex[]{} aren't expanded

I've to build an individual register with \sindex[]{} from the splitxdx package from an outside generated TeX code. The call name of people with two firstnames is sometimes put in braces, sometimes ...
1
vote
1answer
83 views

Refers to a node on a chemfig inside a node in a tikzpicture. Macro definitions

Consider the minimal example: \documentclass[12pt]{article} \usepackage{tikz} ...
3
votes
1answer
39 views

Macro expansion and href with hyperlink

I have very simple question I hope! I am writing a book on MPASM (PIC) assembler and there will be very many similar links to programs, hex files, videos etc. These will be enclosed in a standard ...
5
votes
2answers
57 views

LaTeX3 Expansion without \exp_after:wN

LaTeX3 reduces the need to use \expandafter/\exp_after:wN tremendously. But what is the LaTeX3 way for this problem? \documentclass{article} \usepackage{expl3} \begin{document} \ExplSyntaxOn ...
9
votes
1answer
244 views

“Flatten” macros prior to sharing LaTeX file

Is there a way/an existing tool to process a LaTeX source document such that for a given list of macro definitions (using \newcommand), calls to those macros are replaced by their expanded version? ...
2
votes
1answer
52 views

In expl3, how do I smuggle in a three arguments when threading sequences?

I've got some code which essentially works as in this MWE: \documentclass{article} \usepackage{xparse} \ExplSyntaxOn \tl_new:N \l_aellett_current_choice_tl \tl_new:N ...
11
votes
1answer
134 views

Expansion of verbatim material

I am passing a file name in the command line which contains underscores and would like to print the name of the file in the resulting PDF. So, need some expansion magic so that the output is: The ...
18
votes
2answers
416 views

Could someone further elucidate expansion, catcodes, and scantokens…?

In response to my question "With TikZ is it possible to pass the node content through a preprocessor?", @MarkWibrow suggested a solution using \scantokens. {\catcode`\_=13 ...
1
vote
1answer
64 views

How to parse a macro that contains a \let?

My situation is similar to, but hopefully different from How do I ‘expand’ a control sequence \let to a character?, as that question does not admit a positive answer. I want to parse, not expand, but ...
3
votes
1answer
61 views

Expand arguments in string substitution macro

Rewritten as minimum non-working example: \documentclass{article} \makeatletter \usepackage{xstring} \usepackage{xparse} \newcommand\textfromcase[1]{% \IfEqCase{#1}{% for the purposes of this ...
3
votes
1answer
52 views

Expansion for Macro to pass to scaleBox

I am trying to calculate some width in a macro and use the macro for scalebox. However I get a flood of errors when I try to pass the macro to scalebox. MinimalExample: \documentclass{article} ...
0
votes
0answers
61 views

Ignoring parts of text inside macro

Consider the following code: \documentclass{book} \usepackage{pgffor} \begin{document} \newcommand\containers{ \cont{aaa{\bf don't xstring me}aaa} \cont{bbb\large bbb} ...
4
votes
2answers
117 views

Conditional horizontal lines in tables

I am trying to typeset data that is read from CSV files using the csvsimple package. In the input data, there is a column that will tell me where to place a horizontal line between the rows. (In the ...
4
votes
2answers
44 views

Appending a command with evaluated parameters to a macro

I'm trying to have a command \appendtocmd that does that: \def\contents{Files:} \def\value{yo man} \appendcmdto{contents}{section}{\value} contents contains now "Files: \section{yo man}" so when I ...
4
votes
3answers
154 views

Expansion Issues When Passing TikZ Styles to Macro Created by Macro

I'm struggling (again) with expansions. This time I have a generic function \misdirection that creates a TikZ environment subject to a few options. Then, I create a macro \freezeStyle that creates a ...
4
votes
2answers
103 views

Passing the string value of a variable

The MWE bellow uses exsheets package to print the solutions to questions at the end of a book. The code doesn't work as it should as it seems to be an expansion issue. When, instead of ...
6
votes
2answers
247 views

Use input inside a spreadtab environment with calculations

My aim is to create a command for inserting tables, which will format the table, and add calculations on its values, given a file containing the raw data of the rows only. ...
9
votes
4answers
182 views

Apply command to list of elements separated by \and

I am trying to build a command similar to the \author command. It takes one argument with is actually a list of arguments separated by \and. The command needs to apply another command like \underline ...
4
votes
1answer
48 views

Defining xkeyval keys within a loop

I have a project for which I make extensive use of the great xkeyval package. However, I'm still struggling with some more extravagant things. For example, I want to use enumerated keys (key1 to keyN, ...
7
votes
2answers
168 views

How to use the total page count in a conditional expression?

I would like to have different footer or page style depending on whether the document has one or more pages. I am not very experienced with TeX programming, so the answers about "Comparing an argument ...
3
votes
3answers
91 views

\input{} as argument for \inputgraphic{}

I got a question very similar to this post (\includegraphics{\input{|shell command}}) which unfortunately hasn't been really answered. The aim is to make a command that invokes a python script to ...
4
votes
1answer
75 views

ConTeXt: Macro within macro for URLs

Background Would like to define a base URL that can be reused by other macros. Problem Using the \goto macro requires a fully expanded URL. Minimum Working Example Here's code that illustrates ...
10
votes
1answer
188 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 ...
4
votes
1answer
76 views

Expanding arguments to pgf/tikz styles

In an answer on this site is proposed a method to draw arrows on paths. For example, using the style [arrow inside={pos=0.2}] will put an arrow at position 0.2 on the path : \begin{tikzpicture} ...
8
votes
3answers
237 views

Arguments possibly delimited by \bgroup and \egroup

I still don't see (and haven't thought about) pros and cons of making available the arguments as \foo{…} or \foo\bgroup …\egroup (or even unbalanced, \bgroup …} and {…\egroup). But I'm curious about ...
15
votes
2answers
186 views

\expandafter with \uppercase ordering

As I understand it, the behavior of \expandafter is such that if \a and \b are macros, then \expandafter\a\b will first expand \b then \a. But my understanding must be wrong, because I don't ...
4
votes
4answers
184 views

Expand a macro with parameters in tabular head

My eventual goal is to create my own tabular-like environment in which all entries are in math-mode by default, let's call it fancytable. (One requirement is that the first column be separated from ...
14
votes
1answer
166 views

Workaround for open lualatex bug in \scantokens?

As package author I am in need of writing a manual with lots of examples. Now I started to make heavy use of lualatex in order to speed up operations which take a long time in TeX (of my package, not ...
3
votes
1answer
78 views

Dump command as readable text?

Is it possible to dump the expanded form of a command as text? E.g. when I write a macro \newcommand{\mytest}[1]{\texttt{#1}} I would want to define a macro \mydump such that ...
9
votes
3answers
258 views

Completely expandable loop macro that also works in tabular

Since I normally use tikz in my documents, I mostly use the \foreach \x in \list loop to repeat things. However, this famously fails in tabular environments and also everywhere where things must be ...
3
votes
0answers
98 views

\if and \fi inside different \def macros

Recently I failed to solve specific task in LaTeX. I wanted to make document with several sections, each divided on several subsections. Each section I had placed to separate files, and used \input ...
3
votes
2answers
78 views

How to expand a macro to use it inside a question in AMC?

Context I'm trying to use AMC to produce an exam with code in it. However, the use of verbatim code inside the questions is beyond the scope of the package. They suggest to declare boxes and used ...
10
votes
4answers
391 views

Changing the behavior of $$ but not of $

I am trying to set things up so that occurrences of $$ are replaced by \] if in math mode, \[ otherwise. My strategy is to make $ active and have it behave differently depending on whether the ...
0
votes
0answers
52 views

Prepend and append options to options list in environment

I need to define a macro superenv that expands to the usage of an environment which accepts key-value options. superenv should have three arguments: the environment name, the list of options, and the ...
51
votes
3answers
1k views

Advantages and disadvantages of fully expandable macros

As I currently understand them, fully-expandable macros are analogous to pure/effect-free functions in functional programming. Correspondingly, things that are not expandable, such as \def, are ...
2
votes
0answers
109 views

Checking if first portion of an environment's content is empty

Motivation: I am working on a very personalized Exercise/Answer package for my colleagues. The exercise, exsheets, etc. packages don't do what I need. To accomplish this, I create an exercises ...