Concealment of \citet and \citep from natbib

[kiryph]

I am wondering whether the concealment of \citet and \citep from natbib can be improved.

Here a screenshot from the documentation of natbib

The corresponding code is

\documentclass{article}
\usepackage{natbib}

\begin{document}
\citet{jon90}
\citet[chap.~2]{jon90}
\citep{jon90}
\citep[chap.~2]{jon90}
\citep[see][]{jon90}
\citep[see][chap.~2]{jon90}
\citet*{jon90}
\citep*{jon90}
\end{document}

Currently concealed as following

The most obvious change could be:

• show \citep*?{jon90} with parentheses instead of square brackets (third and last line).

Prepend optional parameters and replace inner brackets with spaces

• Conceal \citet[chap.~2]{jon90} as [chap. 2 jon90]
• Conceal \citep[see][]{jon90} as (see jon90)
• \citep[see][chap.~2]{jon90}. Here the chapter reference becomes completely invisible. I would at least show it. Showing it with less square brackets, e.g. as (see chap. 2 jon90).
• for \citet one could drop the surrounding square brackets. Here I am not so sure.

I am not totally sold on all my suggestions and what is possible to mimic natbib functionality

[lervag]

The first one seems simple and I've fixed it already. The other ones will require some more thought.

• Conceal \citet[chap.~2]{jon90} as [chap. 2 jon90]

• Conceal \citep[see][]{jon90} as (see jon90)

These are quite hard. We are parsing from left to right, and we are parsing group by group. Currently, I'm relying on nextgroup= and I'm allowing two optional groups:

vimtex/autoload/vimtex/syntax/core.vim

Lines 2144 to 2155 in 6f7e507

	syntax match texCmdRefConcealed "\\citet\?\>\*\?" conceal
	\ skipwhite nextgroup=texRefConcealedOpt1,texRefConcealedArg
	call vimtex#syntax#core#new_opt('texRefConcealedOpt1', {
	\ 'opts': g:vimtex_syntax_conceal_cites.verbose ? '' : 'conceal',
	\ 'contains': '@texClusterOpt,texSpecialChar',
	\ 'next': 'texRefConcealedOpt2,texRefConcealedArg',
	\})
	call vimtex#syntax#core#new_opt('texRefConcealedOpt2', {
	\ 'opts': 'conceal',
	\ 'contains': '@texClusterOpt,texSpecialChar',
	\ 'next': 'texRefConcealedArg',
	\})

That is a simple but effective implementation.

To enable what you are asking, we would instead need to somehow match the entire optional groups in one go. It may be possible, but I don't quite see how to do it. Perhaps we can use the pattern offsets here (:help syn-pattern-offset) with end="{"me-1 or something similar. Then we could conceal any ]\_s*[ by a single space character. I would need to experiment a bit with this.

• \citep[see][chap.~2]{jon90}. Here the chapter reference becomes completely invisible. I would at least show it. Showing it with less square brackets, e.g. as (see chap. 2 jon90).

Yes, I agree. I'll find a way to only hide the second option if it is empty.

• for \citet one could drop the surrounding square brackets. Here I am not so sure.

I think having the square brackets makes it easier to recognize that this is a concealed \citet command, and as such, is useful.

[kiryph]

It may be possible, but I don't quite see how to do it.

Do not invest too much time in this issue. If there is no obvious way, keep the current way. It works.

Yes, I agree. I'll find a way to only hide the second option if it is empty.

That would be great and would resolve, from my point of view, the most urgent part of this issue.

I think having the square brackets makes it easier to recognize that this is a concealed \citet command, and as such, is useful.

Agreed. Leave it as it is.

[lervag]

Then I believe the last patch should suffice. Clearly, this is not perfect, but it is not too bad either.

[kiryph]

Thanks. Now the concealed lines look like

And yes, now one can see in line 10 the chapter reference.