How can I get the effect of indexonlyfirst for a single glossary?

Question

Consider the following document:

\documentclass{article}
\usepackage{glossaries-extra}
\newglossary[nlg]{notation}{not}{ntn}{Notation}
\makeglossaries
\newglossaryentry{symb:c}{type=notation,name=$c$, description=the speed of light}
\newglossaryentry{symb:m}{name=$m$, description=mass}

\begin{document}
Referencing my glossary items: \gls{symb:c},  \gls{symb:m}.
\newpage
Referencing my glossary items again: \gls{symb:c},  \gls{symb:m}.

\noindent\rule{\textwidth}{0.4pt}

\printglossaries
\end{document}

(and never mind things like acronyms.)

I want the "Notation" glossary to only show the first page on which a term was referenced; but I want the general glossary (or other glossaries) not to be affected. So, I can't just use indexonlyfirst as a package option.

What do I do instead?

Answer 1

You can use the category attribute indexonlyfirst (not to be confused with the package option of the same name).

\documentclass{article}

\usepackage{glossaries-extra}

\newglossary[nlg]{notation}{not}{ntn}{Notation}
\glssetcategoryattribute{notation}{indexonlyfirst}{true}

\newglossaryentry{symb:c}{type=notation, category=notation, name=$c$, description=the speed of light}
\newglossaryentry{symb:m}{name=$m$, description=mass}

\makeglossaries

\begin{document}

Referencing my glossary items: \gls{symb:c}, \gls{symb:m}.

\newpage

Referencing my glossary items again: \gls{symb:c}, \gls{symb:m}.

\printglossaries

\end{document}

If you use a wrapper macro for defining the notation entries (or all of the other ones), you can set the category in the definition of that wrapper macro (the built-in wrappers like \newabbreviation already do that) and just have to set the category attribute for the correct category.

If you do define the entries for all of your glossaries directly with \newglossaryentry, you can set the category for all of them using \glsforeachincategory after the definitions. (This feels clumsy, but I could not find any more elegant way to do it.)

\documentclass{article}

\usepackage{glossaries-extra}

\newglossary[nlg]{notation}{not}{ntn}{Notation}
\glssetcategoryattribute{notation}{indexonlyfirst}{true}

\newglossaryentry{symb:c}{type=notation, name=$c$, description=the speed of light}
\newglossaryentry{symb:m}{name=$m$, description=mass}

\makeatletter
  \glsforeachincategory[notation]{general}{\@temp@glsry}{\@temp@label}{%
    \glsxtrsetcategory{\@temp@label}{notation}%
  }
\makeatother

\makeglossaries

\begin{document}

Referencing my glossary items: \gls{symb:c}, \gls{symb:m}.

\newpage

Referencing my glossary items again: \gls{symb:c}, \gls{symb:m}.

\printglossaries

\end{document}