3

This is a follow up to my earlier question here: Detect catcode of next character?

What I want to do: Count the number of " used in the document body. I am not using " for purposes such as math, babel shortcuts, or Unicode characters. Just dialog quotations (fiction writing, English).

I hunted around various packages, and see that polyglossia has gloss-dutch, which sets some accented characters to be active. This is done withing a \def macro. It looked like just what I need. To my surprise, it works when I write the code not within a \def, but fails when I write the code within a \def (inaccessible). MWE, which works as-is:

\documentclass{article} % Compile using lualatex.
\usepackage{fontspec} % Less-minimal exaple would need this.
\defaultfontfeatures{} % Reset, to avoid tlig for this MWE.
\newcounter{dblq}
\def\shazam{} % Placeholder.

% To see the problem, uncomment/comment:


% Uncomment these 4 lines:
%\def\shazam{
%  \catcode`"=13
%  \def "{”\stepcounter{dblq}}
%}


% And apply comment to these two lines:
\catcode`"=13
\def "{”\stepcounter{dblq}}


\begin{document}
\shazam


"What in the world," he asked, "is happening here?"


\typeout{DBLQ=\arabic{dblq}}
\end{document}

Reason for lualatex is that I use only utf-8 with fontspec.

I have tried various random changes such as removing space, using \let, etc. No joy. Also fails with \AtBeginDocument.

rallg
  • 2,379
  • that's expected and same as "you can not use verb in the argument of a command) move the catcode setting before the def – David Carlisle Sep 29 '23 at 22:31
  • @DavidCarlisle Alas, in the "real" usage (rather than MWE) the code sits within a hook (such as \AtBeginDocument) and the problem also arises there. But if I change the catcode outside the hook, it works. But I do not know if that would cause potential problems, with other items loaded at the hook. – rallg Sep 30 '23 at 18:12
  • no the catcode setting only affects the characters read from the file it has no effect at all on tokens so if you set it, add to the hook and set it back, it ony affects characters added on those lines – David Carlisle Sep 30 '23 at 18:18

2 Answers2

5

setting \catcode affects the conversion of characters in the input to character tokens but it has no effect at all on character tokens.

In

\def\shazam{
  \catcode`\"=13
  \def "{”\stepcounter{dblq}}
}

the body of the command definition has been tokenized with a catcode 12 " so the \catcode setting does not affect this (but would affect following text) and \def " is a syntax error.

\catcode`\"=13
\def\shazam{
  \def "{”\stepcounter{dblq}}
}

defines the command with active " (even if " is not active at the point \shazam is used.

David Carlisle
  • 757,742
  • Thanks. I see that others found this useful, but my actual usage (not MWE) puts the catcode and shazam inside a hook, and there it causes problems. Will investigate more. – rallg Sep 30 '23 at 18:14
  • you need to have the catcode setting outside the hook setting (you may also want it inside the definition of \shazam to affect following characters. @rallg – David Carlisle Sep 30 '23 at 18:16
  • 1
    Will invesitgate. My limited understanding of catcodes is that changing a catcode involves taking the cat to a veterinarian. – rallg Sep 30 '23 at 18:21
  • See my added answer, below yours. Possibly of general interest. – rallg Oct 01 '23 at 18:45
0

After digesting what David wrote, and re-inspecting the code for parts of babel and polyglossia, I was still mystified. Their code defined active characters within a macro, but in a manner that did not work for me. Understand that for reasons unrelated to the original question, I need to activate and define the character \AtBeginDocument or perhaps \AfterEndPreamble (etoolbox).

Then it dawned on me: The other code was loaded using \usepackage or \RequirePackage. Maybe those macros did something magical? Yes! So here is something that works, and may be useful to others:

  1. Create file dblq.sty containing this line:
\ProvidesFile{dblq.sty}[2023/10/01 v0.01 LaTeX file (double quotes).]
\catcode`\"=13
\def "{”\stepcounter{dblq}}
\AtEndDocument{
  \catcode`\"=12
  \typeout{You used \arabic{dblq}\string ".}
}
\endinput

Then put it next to the document, or command-line mktexlsr to find it.

  1. In the document class (or Preamble}:
\newcounter{dblq}
\AtBeginDocument{\RequirePackage{dblq}}
  1. Here is another MWE that illustrates its usage. This assumes that file dblq.sty is already there:
\documentclass{article}
% \usepackage{fontspec} % If building with lualatex.
\def\doesNotCount{"Hello World," they said.}
\newcounter{dblq}
\AtBeginDocument{
  \def\uni#1{No\obeyspaces} % This MWE only, pdflatex.
  % \def\uni#1{{\char"#1}\obeyspaces} % uncomment for lualatex
  \RequirePackage{dblq}
}
\begin{document}
\def\doesCount{"Hello Again," they said.}
\doesNotCount\par
\doesCount\par
"Hello to you, too," they replied.\par
"Deise is sch\"one," said Hans.\par
Finally, "\uni{2116} kidding!" they shouted.\par
\end{document}

That correctly counts 8 doublequote. The ones in \doesNotCount are not counted, because they are written prior to activation. The active character does not affect \"o and is not counted. Although \uni might not be necessary, I use it for my own purposes, so I wrote it here.

I do not use babel/polyglossia shortcuts, so I do not know if this interferes with them.

EDIT: Modified per suggestion in comment.

rallg
  • 2,379
  • It would be much better to add \catcode\"=13...\catcode`"=12todblq.styso that if used in the normal way via\usepackage{dblq}` in the preamble it does not give low level errors. – David Carlisle Oct 01 '23 at 19:03
  • Will do. Thanks for looking. I intend to use this technique for trapping usage of " when I should have used tlig or pasted Unicode characters. The goal is to reduce doublequotes to 0. – rallg Oct 01 '23 at 19:05