Using hyphen as a letter in command names

Question

I am using hyphen as a letter for command names. But I allow users to rename them if necessary. Then use \catcode`-=11. Suppose I keep the hyphen as a letter in command names, I wonder if users could encounter problems if they keep \catcode`-=11 for the entire document.

Briefly looking around there are a few packages that parses token list consist of - https://tex.stackexchange.com/questions/112831/typesetting-transition-metal-cluster-in-mhchem/112838#112838 https://tex.stackexchange.com/questions/323342/mfuhyphentrue-is-undefined-control-sequence/323348#323348 — user202729, Sep 27 '22 at 00:32
did you mean to ask if there would be problems if they keep catcode 11 ?? — David Carlisle, Sep 27 '22 at 07:13
Have started editing my questions straight away after seeing comments. Thank you so very much David. — Veak, Sep 27 '22 at 11:23

score 3 · Answer 1 · answered Sep 27 '22 at 08:10

Setting the catcode of the hyphen to letter in a document is a very bad idea. A few examples for a test:

\documentclass{article}
\usepackage{tikz}
\begin{document}
\catcode`-=11
\tikz\draw(0,0)--(1,0); %errors
some long-word-with-hyphenation %errors
\setlength{\parindent}{-1cm} %errors
\end{document}

which errors with

! Package tikz Error: Giving up on this path. Did you forget a semicolon?.
See the tikz package documentation for explanation.
Type  H <return>  for immediate help.
 ...
l.86 \tikz\draw(0,0)-
                     -(1,0);
? 
! Undefined control sequence.
l.88 some long-word
                    -with-hyphenation
? 
! Undefined control sequence.
l.88 some long-word-with
                          -hyphenation
? 
! Undefined control sequence.
l.88 some long-word-with-hyphenation
? 
! Missing number, treated as zero.
<to be read again> 
                   -
l.90 \setlength{\parindent}{-1cm}
? 
! Illegal unit of measure (pt inserted).
<to be read again> 
                   -
l.90 \setlength{\parindent}{-1cm}

score 2 · Accepted Answer · answered Sep 27 '22 at 08:29

Some LaTeX constructs that fail if - is catcode 11:

\documentclass[a4paper]{article}
%\catcode`-=11
\usepackage{array}[2021-01-01]
\usepackage{textgreek}
\begin{document}
aaa-bbb-ccc aaa-bbb-ccc aaa-bbb-ccc 
aaa-bbb-ccc aaa-bbb-ccc aaa-bbb-ccc 
aaa-bbb-ccc aaa-bbb-ccc aaa-bbb-ccc 
aaa-bbb-ccc aaa-bbb-ccc aaa-bbb-ccc 
aaa-bbb-ccc aaa-bbb-ccc aaa-bbb-ccc
$ \cos-x=\cos x$
$\alpha-\beta$
\textalpha-rays
\verb-\SomeCommand-
\begin{tabular}{lll}
  1&2&3\
  \cline{2-3}
  a&b&ct
\end{tabular}
\end{document}

If you use - internally like @ classically or _ in expl3 you could provide \DashLetterOn and \DashLetterOff like \makeatletter/\makeatother to allow local access to that syntax in the preamble, but do not use - for commands intended for document use.

Using hyphen as a letter in command names

2 Answers2