Bug: Inconsistent styling of markers in `item-by-item-fn`

[Jack-Sandberg]

The item-by-item-fn seems to treat the first item differently from the others by including the marker in the styling of the first item, but not the others. Consider the example:

#item-by-item-fn("current-highlight")[
  - First
  - Second
  - Third
]

In the first slide, the marker and the text are highlighted but in the second and third slide only the text is highlighted.

The desired behavior should either be to always highlight the marker or never highlight it. More generally, the question is whether the marker should be part of the content and follow its styling or not.

For highlighting, it seems strange to highlight the marker. However, when using "past-faded" or "past-progressive-faded", I would prefer if the markers follow the styling of the text and also fade. Currently, they do not:

#item-by-item-fn("past-progressive-faded")[
  - First
  - Second
  - Third
  - Fourth
  - Fifth
]

Related issues: #264 and #347

[zral0kh]

yes i know this is somewhat typst's fault we would need to do some special thingies to get this right.

and the differentiation would require a flag like: affects-markers: bool

for whether we can affect the markers in general and consistently idk i guess yes but with a lot of extra work

[zral0kh]

but glad its getting used

[zral0kh]

bc of work on the semi-transparent-cover or rather the idea of it, i noticed that fixing this will require some refactor and i won't have time for it until some time in june. if smo could take a look at the new alpha-changing-cover when it's done and implement the little tricks to the item-by-item-fn then you can have this sooner.

the idea goes as follows: markers are also text and we simply affect them with show regex(".+"): .... if we don't want that we need to traverse to the bodies of the list item elements and apply the styling there. this would make it consistent.

[zral0kh]

e.g, this means we don't use the normal highlight function anymore but instead implement it ourselves.
or bc highlight is only highlighting the one element we could have a separate implementation that just highlights the list item body, not the item itself. this should also work. but ofc its not the general solution