Fix uncover bug with list items in 0.12

[TimotheAlbouy]

Hello,

In typst 0.12, when we uncover a list item, its bullet already appears in the previous slides.

Example:

#import "@preview/polylux:0.3.1": *

#set page(paper: "presentation-16-9")
#set text(size: 25pt)

#polylux-slide[
  This is a list:
  - this is the first item
  #uncover(2)[
  - this is the second item
  ]
]

First slide:

[andreasKroepelin]

Oh here we go again... I think this problem appeared in the early days of Polylux already. Might be worth to investigate whether it's an regression within Typst.

[andreasKroepelin]

No wait I think it's always been like that? If you #hide a bullet list item, the bullet point is still shown. Are you sure this issue is new in Typst 0.12?

[TimotheAlbouy]

Hum when I switch back to 0.11.1 I get the correct output:

I'm on the webapp, and I switch between the compiler versions "Latest (Typst 0.11.1)" and "Typst 0.12.0 Testing" in the settings. I use the exact same code I posted here.

[andreasKroepelin]

Can you try out

- abc
#hide[- def]

?

[TimotheAlbouy]

Can you try out

- abc
#hide[- def]

?

This also produces the bug of my first message (I'm on 0.12).

[andreasKroepelin]

But does it behave the same on earlier Typst versions?

[TimotheAlbouy]

You're right, #hide[- def] also produces the bug on 0.11.1.

[rmburg]

Workaround:

#show hide: it => {
  set list(marker: none)
  set enum(numbering: n => [])

  it
}

I'm interested in integrating this fix into polylux.
@andreasKroepelin I looked around the code for a bit and could not find a good place to put such a global show rule, the best i could find was inside the polylux-slide function.
Do you have a better idea on where to put this?
Touying uses a global show rule, templates use something like #show: touying-slides.with(...)

[andreasKroepelin]

Workaround:

#show hide: it => {
  set list(marker: none)
  set enum(numbering: n => [])

  it
}

I'm interested in integrating this fix into polylux.

Clever idea! Let's use that.

@andreasKroepelin I looked around the code for a bit and could not find a good place to put such a global show rule, the best i could find was inside the polylux-slide function.

That sounds like a good place to put it.

Do you have a better idea on where to put this?
Touying uses a global show rule, templates use something like #show: touying-slides.with(...)

Yeah for Polylux it's the same with templates (Touying started as a fork of Polylux) that they each have a "global" show rule. But I envision Polylux to work more like a library than as a framework so core functionality should work without such show rules.

[rmburg]

Alright, I'll open a PR for this. Thanks for the insight!
To clarify, the touying-slides function is called by the templates, and provided by touying.
That's where they put show rules that apply across all themes.