{conditionals} is about macros like \if and \ifx that may execute other macros depending on whether certain conditions are true or not. Popular packages are {etoolbox} and {ifthen}.

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5
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5answers
200 views

new command with cases?

This has been answered here for text outputs with the use of \IfEqCase from the xstring package. But if I want to use the output as a value to set a parameter in a function, it fails. Here is my MWE: ...
8
votes
2answers
66 views

“Extra \else” and inserted “\inaccessible” when using textbf with pgffor

I'm getting errors whenever I try to make \textbf interact with pgffor and xparse. Here's an MWE that gives ERROR: Extra \else and ERROR: Missing control sequence inserted at the end of the \coljoin ...
13
votes
2answers
168 views

Why does this use of `\expandafter` not work?

I've written the following code: \newif\ifconsecutive \consecutivefalse \newcommand{\myfirst}[1]{#1\consecutivetrue\expandafter\consecutivefalse} \newcommand{\mysecond}[1]{\ifconsecutive ...
21
votes
2answers
3k views

Use “default” figure if file is missing?

I was recently in charge of organizing all of the references and labels in a very large scientific proposal document. My workflow typically involved compiling the document, seeing a "There were ...
2
votes
1answer
55 views

Customizable inclusion of frames-slides from a huge Beamer presentation [duplicate]

I have one master-huge beamer presentation having lots of frames. Depending on the audience I wish to customize, say, for lay audience I will just include basic slides, for experts I wish to include ...
3
votes
1answer
63 views

How to use conditional (if statements) with data from acronyms?

I am using acronym for autocomplete my text like mailing functions. So I want the long text from acronym using all the time, and I am using \acro{}{} to define, so \acro{Maria}{f} - for me shows that ...
5
votes
1answer
72 views

How to detect if \thepage is undefined?

The sig-alternate class by default disables page numbers, which breaks mparhack (amongst other things). How can I include tex code only if \thepage is properly defined? I tried \ifcsname and ...
5
votes
1answer
77 views

How to use If with on variables

I want to create my own documentclass and use some variables for creating titlepages etc with it. So what's the best way/package for doing this? the class file: \ProvidesClass{myOwnClass}[v0.1] ...
6
votes
1answer
203 views

How to do a conditional line break

I want to know how to do a conditional line break. Whenever the error message "There is no line to end here" comes, I want to disable the line break, otherwise to enable it, with a \\ command or ...
0
votes
2answers
69 views

newcommand with variable number of arguments

I have seen several related questions, but none seems to address specifically this. I would like to define a command that accepts a variable number of arguments. Something like ...
6
votes
2answers
103 views

Suppress month and day for journal articles and maintain for a newspaper articles

I haven't found a solution yet for this problem. I want to suppress month and day (if present) from all journal articles in bibliography but I at the same time I want to indicate year, month and day ...
1
vote
1answer
42 views

Macros with \fi for showing and hiding proofs [duplicate]

I would like to be able to globally showing and hiding proofs on a document, and be able to use macros to open and close the proof environments. Here is my current MWE: \documentclass{article} ...
3
votes
0answers
29 views

Changing a macro's output depending on immediate context [duplicate]

I've set up a macro for differential parts as so: \newcommand{\dd}[1]{\,\mathrm{d}#1} which is useful for differentials at the end of integrals because of the space. (I realise the argument ...
2
votes
1answer
29 views

textpos toggling noshowtext option

Is there a way of toggling the textpos option [noshowtext]? I would like some textboxes to show the frame but not the text. And others to show both frame and text, but can't seem to find a way of ...
2
votes
1answer
489 views

how to use memoir \ifoddpage

Why does \ifoddpage seem to always return false in the following example? This is related to question 6143 on this same forum. I'm using XeLaTeX to produce a pdf file (i.e., xelatex test.tex) ...
10
votes
3answers
182 views

Global Conditional

I'm writing a set of notes for my students on trigonometry. At present, they have not met radians, which comes next year. I would like to use the same set of notes for them, but this year, give them ...
16
votes
4answers
2k views

Making switch/case with etoolbox's \ifdefequal

I've got a define such as \def\doctype{SomeString}. \doctype can take on one of five values. I want to do something like a switch statement in a programming language, i.e. (pseudocode): switch ...
8
votes
1answer
173 views

Problems understanding definition of \newif

Reading http://profs.sci.univr.it/~gregorio/introtex.pdf, I have come across the definition of \newif on page 75: \def\newif#1{\@ifdefinable{#1}{\@newif#1}} \def\@newif#1{\count@\escapechar ...
6
votes
2answers
142 views

Detect whether I'm in a \footnote?

How do I detect whether I'm in a \footnote environment or not?
3
votes
2answers
64 views

Detect whether I'm on a left- or right-hand page? [duplicate]

How do I detect whether I'm on a left- or right-hand page? I would like to define a custom command with a conditional statement that executes a certain command if it's on a left-hand page and another ...
0
votes
0answers
27 views

Make left-hand pages' `\marginpar` text right-aligned [duplicate]

\marginpars only appear on the right margins of right-hand pages of my manuscript. For left-hand pages, they are are so far to the left that they aren't even on the page. The reason is because the ...
2
votes
1answer
117 views

How to get float numbers as parameter of \newcommand

I have defined a \newcommand function like into this code: \documentclass{scrartcl} \usepackage{pbox,calc} \newcounter{pointsExo} \setcounter{pointsExo}{4} \newcounter{pointsSousTotal} ...
5
votes
2answers
96 views

Is there a way to query the page size that I have set in the memoir class?

In my preamble, I have: \documentclass[a5paper,10pt,oneside,onecolumn,openany]{memoir} I would like to later define some layout options based on the value of the page size, which in this case is ...
6
votes
2answers
98 views

How to distinguish between Metafont and MetaPost?

Background I'm trying to make a nice SVG out of Knuth's Dangerous Bend symbol based on his own code, for which the obvious tool to use is MetaPost. However, I'd prefer to still be able to process the ...
4
votes
1answer
153 views

FancyVerb Error when using minted in a \ifthenelse

I'm new to LaTeX and wand to add some code with minted, which will only be rendered, when a \boolean variable is true. Here's my code: \documentclass{article} \usepackage {minted} \usepackage ...
4
votes
1answer
89 views

Command to disable environments [duplicate]

I have defined an environment called answer that displays the answer of a question of a test I'm supposed to prepare. The idea is to compile a version where the answers are displays and one were they ...
2
votes
1answer
177 views

TikZ-ifthen: decision making in a \foreach statement

Disclaimer I am not a programmer so I may not use the proper terminology to express myself. Please correct me if need be. Preamble I'm trying to draw a sinusoidal function and some arrows at ...
5
votes
1answer
61 views

How to check whether two labels fall on the same page?

I'd like to have something like 5--10 in the header of an article (my document is a journal issue) if it spans the pages 5-10, and 5 (as opposed to 5--5) if it is short and fits on one page. I use ...
4
votes
1answer
68 views

How to swap subcaptions of zoomboxes?

I greatly appreciate the zoomboxes given in this question: How to create magnified subfigures and corresponding boxes for portions of a large image. As the comments thread is already long enough I ...
4
votes
1answer
270 views

Conditions for fancy chapter title

I use a book class and here is a part of my fancy title page for the mainmatter chapters. \newlength\chapterwidth \settowidth\chapterwidth{\huge\chaptertitlename} \titleformat{\chapter}[display] ...
32
votes
3answers
3k views

Difference between \if and \ifx

I try to understand the subtleties of TeX programming, but it is not always easy. For example, in the following code : \def\first{abc} \def\second{abc} \ifx\first\second OK!\else false \fi I ...
1
vote
1answer
94 views

Conditional formatting in moderncv

We busily discussed a method of implementing conditional statements in the moderncv class (Conditional content in moderncv) last month. Sean Allred came up with a great solution to solve this (see ...
21
votes
1answer
127 views

Is implicit `\relax` in conditionals explained anywhere in the TeXbook?

I have been relying for years on TeX's behavior where, say \if1\fi expands to nothing and \if1\else\fi does the same. In the second case TeX inserts an 'implicit' \relax when it tries to expand \else. ...
16
votes
2answers
166 views

Does etoolbox's \ifboolexpr use lazy evaluation?

In other words, is bool{testB} evaluated at all in this example code? \newbool{testA} \newbool{testB} \booltrue{testA} \booltrue{testB} \ifboolexpr{ bool{testA} or bool{testB} }{OK}{Something's ...
5
votes
1answer
62 views

how to use conditional to define different \begin and \end environment at compile time

I just need little help on the syntax for this. I am using tex4ht, and I get an error when I use empheq for the align environment. I want to build this TeX file both in pdflatex and htlatex. I ...
6
votes
1answer
62 views

Conditional based on character following the macro

Basically, I would like to something like \xspace does, i.e. the meaning of the macro should depend on what is following it. So for example if I say \mymacro a it might expand to foo, and if any ...
1
vote
0answers
62 views

Special conditionals (TeX)

Is there a way to compare strings rather than single tokens? Is there a way to check if a parameter in a command is a string or a single character? If there is either, how do I?
5
votes
1answer
135 views

Only show header if section number > 0

The current section name + chapter.section number is shown in the header. This is normal behaviour (what I want). Example: How can I remove the header text, if there is no section on the page. The ...
0
votes
0answers
22 views

Conditional on counter definition (TeX) [duplicate]

Is there a way to make a conditional where the test is the definition of a counter with a specific name, i.e. "if there exists a counter named foo, then do [bar], otherwise do [baz]"? If so, how do I ...
2
votes
1answer
138 views

Conditionally Hiding Parts of Bibtex Fields Depending on Language Field Value

I would like to create a document with a bibliography using XeLaTeX with Biber. In the bibliography, there are Chinese books and articles, as well as English or German ones. Some of the authors have ...
7
votes
1answer
100 views

\apptocmd into a conditional—why it does not work?

Why the following MWE does not work while if I comment the conditional it works? \documentclass{beamer} \makeatletter \@ifclassloaded{beamer}{ \usepackage{bookmark} \usepackage{etoolbox} ...
5
votes
1answer
161 views

Nested ifnum conditional groupplots with pgfplots?

I want to use groupplots, and set a variable to conditionally plot the plots. Here is the minimal non-working example: \documentclass{article} \usepackage{pgfplots} \usetikzlibrary{calc} ...
6
votes
2answers
117 views

How do I declare and pass conditions to commands?

I'm new to LaTeX so I'm not quite sure how to proceed with this. I'm trying to have different versions of the same document, depending on which variables are set. What I want is to change the whole ...
1
vote
1answer
164 views

Newcommand returning a boolean value

I'm using etoolbox. How can I create a new command that returns a boolean value? For example if I create the following command: \newcommand\ifkeyempty[1]{ \def\novalue{\pgfkeysnovalue}% ...
0
votes
1answer
192 views

\@ifundefined actually defines macros? [duplicate]

Is it just me or is it a bit illogical that \documentclass[a4paper]{article} \begin{document} \makeatletter \@ifundefined{chapter}{}{} \makeatother \ifdefined\chapter chapter\else no chapter\fi ...
5
votes
2answers
68 views

Does the LaTeX kernel define font-shape macros that expand to `it', `sc', etc.?

I need to perform a test on the current font shape. More specifically, I need to detect whether the current font shape is italic or slanted. Joseph Wright already provided a solution in his answer to ...
1
vote
1answer
79 views

Check the value of a pgfkey

I need to be able to check if the value of a pgfkey is empty or not. A solution I have tried (using package etoolbox): \edef\temp{\pgfkeysvalueof{/path/key}}% ...
4
votes
2answers
75 views

Why is it not possible to embed \if construction in docstrip

I would like to create a DTX files which could be compiled in two different ways depending of a user's choice. One way to get only the user documentation, and another to get user documentation and ...
6
votes
0answers
193 views

Display beamer headline in frames conditional on section and subsection environments

I'm trying to create a beamer presentation (in LyX) where frames conditionally display a headline containing section and subsection navigation depending on (a) whether a frame is in a section ...
4
votes
1answer
91 views

PSTricks, conditional frame size

Consider the following code: \documentclass{article} \usepackage{pst-eucl} \usepackage{siunitx} % LaTeX 3 syntax \ExplSyntaxOn \cs_new_eq:NN \calc \fp_eval:n \ExplSyntaxOff % constants ...