{catcodes} is about "category codes" — an integer number from 0–15 associated to each of the 256 character codes. The category codes indicate the role of a character.

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123 views

Symbolic functions: changing catcodes and \tl_rescan:nn

The goal is to have the user input (for the sake of argument) a linear function in one variable, for example 2*x+3 along with the variable (this isn't crucial) and a value for the variable. I would ...
5
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1answer
210 views

Print a speacial character read by \readline in the same way in the document

I want to read a underscore character from a file with \readline and print it as an underscore in the resulting pdf. But the result is a high point. I've read quite a lot about category/character ...
6
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1answer
192 views

\scantokens in LuaTeX

The eTeX \scantokens command appears to work differently in LuaTeX than it does in eTeX, pdfTeX and XeTeX. Compiling the following test file with any engine other than LuaTeX performs \show+, which ...
5
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3answers
263 views

Automatically fixing catcode output

Using the following macro to redefine catcodes for lua blocks to make programming lua inside tex files more natural has a fault: \def\lua{% \bgroup \catcode`\\=12 \catcode`\{=12 ...
4
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2answers
99 views

Search for tab in external file with filename in another external file (\catcode is not the problem)

This is a quite specific question. I have some code and I'm completely stuck because it won't work for an inexplicable reason. I need to find in which line of an external file there is a tab. I use ...
21
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4answers
4k views

Underscore in textmode vs mathmode

I use _ character often in text mode, so I changed category of underscore: \catcode\_=12, but that applies also to mathmode and now I'm unable to make subscripts with underscore in mathmode. Is there ...
14
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2answers
623 views

Removing double negative signs in equations

Intro: I am attempting to write a macro which can remove any extra negative signs in a general equation: 15.2 + -3.1 would be changed to: 15.2 - 3.1 when using the commands: ...
5
votes
1answer
149 views

StrSubstitute and @ inside and outside \lstnewenvironment

While further working on code for my answer to Different approach to literate programming for LaTeX, I am encountering a problem to which I am sure there is a very simple solution, but it completely ...
4
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1answer
505 views

Generating a catcode table in Latex (with \typeout to terminal)?

I often need to look up a catcode table, and quick searches on the web are rarely satisfying. So I thought, it must be (in the long term) easier to use a Latex function of sorts, to loop through all ...
2
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1answer
81 views

Macros and environments that rely on the distinction between space and newline

In most cases, TeX does not distinguish between spaces and newlines. However, inside some macros and environments this distinction matters a lot. Time for a big list? Please edit the CW answer. This ...
9
votes
1answer
1k views

Is there a counterpart/antidote for \obeylines?

The \obeylines command tells TeX to preserve line endings, which is useful for poetry and various other things. I can limit the effect of \obeylines by wrapping it in a scope, like so: {\obeylines ...
8
votes
1answer
329 views

Passing a TikZ matrix to a TeX macro

When I pass code containing a TikZ matrix to a TeX macro it prints the following error message: ! Package pgfbasematrix Error: Single ampersand used with wrong catcode. \documentclass{article} ...
7
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2answers
436 views

How to emulate a newline without a <return> char?

This works: a^^M% ^^M% b But a real newline is still needed after %. If I remove the newlines and use a^^M^^Mb The result is just a letter a. It seems that, everything after the first ^^M is ...
5
votes
3answers
348 views

Setting catcodes in a group

Can someone explain to my why \foo and \bar are not the same (in the \ifx sense) in this example: \documentclass{article} \begingroup \catcode`|=3\relax \gdef\abc{|} \endgroup \makeatletter ...
6
votes
1answer
751 views

catcode as used in defining Hypergeometric Function

This is perhaps not a very intelligent question, as I am not (of great intelligence nor) well versed in raw tex, even more so \catcode but in the code given in a previous answer there is a use of ...
10
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1answer
202 views

Treating < and > as synonyms for the curly braces { and }

I am exporting photo metadata from a software which seems to be unable to export curly braces correctly. Is there any way to tell LaTeX to treat < as {, and > as }, to keep me from having to go ...
6
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2answers
715 views

Force LaTeX to obey spaces in math mode

I have experienced a very frustrating feature of LaTeX. I have used bnf.tex to be able to write a BNF grammar definition. As I found the notation <some text> very convenient, I decided to use ...
9
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1answer
248 views

Print catcodes in LaTeX with LaTeX3

I have the following MWE which prints the catcode of every character in the list. The input method is: \MyList{`+,{`,},`\%,`a} but I want to simplify as follows: \MyList{+,{,},\%,a} Here the ...
5
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1answer
192 views

Infinite loop on a non-macro token

The following document infinite-loops: \documentclass{article} \usepackage{breqn} \begin{document} \newcommand{\allowbreaks}[2][,]{\begingroup \catcode`#1=\active \scantokens{% \edef#1{% ...
11
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2answers
784 views

“Activate” active characters in argument passed as macro

Let's say I have some macro (\iPrint in the MWE) that internally uses active characters to interpret its argument: \documentclass{article} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} ...
13
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1answer
522 views

How to redefine @ and . to obfuscate email addresses?

I am writing a small package containing macros I intend to use regularly. Among those macros, I have \mailto with the following definition: \@ifpackageloaded{hyperref}{% \def\mailto#1{% ...
12
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2answers
1k views

Removing a backslash from a character sequence

For indexing I wanted to write a macro \macroname that removes leading backslashes from macro names but leaves the names of environments untouched. That is \macroname{\relax} --> relax ...
8
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1answer
1k views

\input only part of a file using catchfilebetweentags package

I would like to include only a part of a .tex file into a different .tex file. The part I want to include is delimited by some comment tags, as it is used by catchfilebetweentags package. I tried the ...
32
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2answers
825 views

No \makeatletter required?

In typing up some small examples that might create errors in LaTeX (for Documents with typical LaTeX errors), I tried the following: \documentclass{article} \def\my@macro#1{-#1-}% This is magic ...
8
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4answers
460 views

Having multiple commands with underscores and numbers that start with same text

Recently me and some friends really got into "making everything compilable". More specifically, we need to do a lot of matlab calculations, and then we need to put the results into a tex document. ...
4
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3answers
1k views

Replace chars with xstring. Catcode problem

I try to do something like this (minimal example): \documentclass[]{article} \usepackage{mathtools} \usepackage{xstring} \newcommand{\foo}[1]{ \StrSubstitute{#1}{:}{\string&}[\fooo] ...
3
votes
1answer
249 views

checking for whitespace inside verbatim environment

I would like to determine whether a line inside a verbatim environment starts with 3 spaces. I'm using pdflatex and the \pdfmatch primitive. I see that the verbatim environment sets the category ...
3
votes
1answer
132 views

Possible to use certain delimiters for macros with fancyvrb?

In this document: \documentclass{article} \usepackage{fancyvrb} \DefineVerbatimEnvironment{AVerb}{Verbatim}{commandchars=\\\{\}} \def\foo#1-#2;{} \begin{document} \begin{AVerb} \foo x-z; ...
3
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2answers
865 views

How listing and verbatim do to escape special character?

I use one macro to display text using texttt style. For the moment this macro is very basic. For example, if I want to use the character _, its catcode must be changed. Is there a clever way to ...
9
votes
3answers
993 views

Changing the catcode of _ in one command?

In the following code, I would like _ to be a simple letter. How can I achieve this ? % Source : http://forum.mathematex.net/latex-f6/forcer-le-retour-a-la-ligne-dans-texttt-t13246.html#p127511 ...
2
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1answer
335 views

A simple implementation of comment/verbatim: drawbacks?

While considering how to exclude \items in Yossi Farjoun's recently active question onlyitems? How to select specific items from an item list, I thought I would do what I proposed in my first answer: ...
9
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2answers
809 views

Change the behavior of carriage return

Define an enhance verse environment, where stroke Carriage return key once make a \\, twice make a \par, three times make a \medskip, four times and more make a \bigskip. An example would be: ...
29
votes
5answers
3k views

Using indentation to automatically begin and end itemize environments

This is a question one might answer with "Why the hell would you want to do it?!", sort of an experiment. What I am looking for is a way to write lists with many levels of nestings (notes for school) ...
2
votes
1answer
499 views

Potential problems from passing macro arguments to \verb

I've been working on a command that will typeset snippets of code within a paragraph. I'm aware of listings and company, but I want something that will just typeset the code verbatim and also allow ...
7
votes
1answer
608 views

string manipulation and catcodes

I want to detect whether an input line contains a certain substring, similar to the problem discussed here: Check if a string contains a given character The complicating problem is that the match ...
10
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1answer
288 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 ...
7
votes
1answer
188 views

Printing a character that has been made active in text and/or math mode?

I am not very familiar with TeX's category codes. If I use \catcode`\|=13 \renewcommand{|}{hello world} then every use of | in my document will be replaced by hello world. However, how would I be ...
13
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3answers
633 views

How do I test for a character, irrespective of catcode?

This came up from Labels in TikZ are incorrectly interpreted, but it's also something I've run into with the braids package, and a couple of other things I've done. Also, from looking at the TikZ ...
7
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2answers
522 views

Active characters after \begin{document}

I'm using XeLaTeX and I want to do automatic repeating of plus sign after breakline. I've found the unoffical package for this but it seems to me a bit overkill (although didn't try it). I tried to ...
4
votes
3answers
272 views

Why does a defined command appear differently in the align environment?

In the LaTeX document shown below, my definition \comp does not show correctly in the align environment. Why it is this the case? ========== Begin LaTeX scripts ============= ...
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vote
0answers
215 views

How to use tikz matrix in a LaTeX command? [duplicate]

Possible Duplicate: Problem with defining shortcuts for TikZ matrices. I tried to use a tikz Matrix in a LaTeX document as the following: \documentclass{article} \usepackage{tikz} ...
3
votes
1answer
276 views

How to prevent \endlinechar=-1 from interfering a loaded EPS image?

I have to work in a block that begins with \endlinechar=-1\relax removing any space at the end of each line. After the \endlinechar=-1\relax, there will be codes related to loading an image ...
13
votes
3answers
926 views

How to get the catcode of a token?

For debugging a complicated macro I would like to print out the catcode of a token. Optimally I would like to have a macro \getcatcode such that, for example, \getcatcode{a} would expand to 10. How ...
2
votes
1answer
585 views

Scope of catcode change for escape character ?

In the following macro, I change the category code for the escape character (\) to "other" (12): \def\xxA{\begingroup \catcode`\\ = 12 \gdef\xxB ##1z{\tt ##1\endgroup} \xxB} How the heck does ...
13
votes
1answer
423 views

Is there a \show for catcodes?

In the course of attempting to out-pedant another mathematician, I wanted to \show the catcode of $ to convince myself that it was a "special" character in ordinary TeX as well as LaTeX. I was just ...
14
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2answers
391 views

Macro to take a character as argument, make it active, then \def it.

I have a XeLaTeX document in which I want some unicode symbols to be auto-substituted, like ¼ → 1/4, » → >>, « → <<. But instead of a long list like \catcode`\¼=\active\def¼{1/4} ...
5
votes
2answers
196 views

Changing catcode for commercial at (@) inside a macro to get it matched in pattern.

This question is related to TikZ: pgfutil-common: pgfutil@in@ - how does it work? and is a result of coping with that problem. I've already read How to change #catcode in a macro, but it didn't help ...
45
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4answers
3k views

What are category codes?

Following on from this question, I'd like to ask a more general question: What are category codes, and what can I achieve by changing them?
6
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1answer
1k views

Using tilde `~` in csname in Beamer

In beamer, I would like to be able to use the tilde character ~ in the name of a command sequence. I tried with adjusting catcodes. While this was successful with the standard article class, it failed ...
15
votes
1answer
869 views

How to change the catcode in a macro

I want to change the catcode in a macro, but it seems it doesn't work. Can anyone help me? \def\A{\catcode`\|=0 |bf{test}} |bf{test} would not work as expect.