Feature Request: more details in fold text

[aquohn]

Describe the solution you'd like
When folding \begin{...} blocks, the fold text just states the \begin{...} part, not any of the arguments. It may sometimes be helpful to display the arguments, for example in the case of \begin{frame} in Beamer. Of course, some environments have horrendously long arguments that would not be useful in fold text, so perhaps this could be implemented as a configurable list of opt-in environments (or maybe a dictionary of environments to the number of arguments to show in fold text).

Describe alternatives you've considered
I could override the foldtext function as per #2532 but this seems like it would be quite beneficial to be upstreamed.

[lervag]

When folding \begin{...} blocks, the fold text just states the \begin{...} part, not any of the arguments. It may sometimes be helpful to display the arguments, for example in the case of \begin{frame} in Beamer. Of course, some environments have horrendously long arguments that would not be useful in fold text, so perhaps this could be implemented as a configurable list of opt-in environments (or maybe a dictionary of environments to the number of arguments to show in fold text).

There is already support for arguments, depending on which environment that is folded. For instance, the foldtext may look like this:

The frame environment also has a slightly complex foldtext function that adds the frametitle if it is found, see e.g. this test file, which looks like this when folded:

Perhaps you can show some examples of environments that do not have the foldtext you would expect?

[aquohn]

I see, I wasn’t aware of that. My own use case is for a custom environment that I have defined, which plays a role similar to the frame environment in structuring my document. Is this a use case you’d be interested in supporting, or would it be better to implement a custom foldtext function for this?

[lervag]

I see, I wasn’t aware of that. My own use case is for a custom environment that I have defined, which plays a role similar to the frame environment in structuring my document. Is this a use case you’d be interested in supporting, or would it be better to implement a custom foldtext function for this?

Then feel free to show that exact environment. It would help me understand what you are asking for more precisely.

[aquohn]

The environment is just

\begin{song}{<song title>}
…
\end{song}

I would like <song title> to appear in the foldtext, or more generally to be able to configure the foldtext function to support such custom foldtexts.