How can I use a show rule to change the text of bullet point lists?

Questions
,
1

I would like to use a show rule to wrap the elements of a bullet point list with a function call. By this I mean the text after the bullet point, not the bullet point itself.

#let taglist(content) = {
  let tags = content.text
    .split(";")
    .map(str.trim)
    .filter(s => s != "")

  tags.map(t => strong(t)).join(", ")
}

#show list.item: it => {
    taglist(it.body)
}

- One; Two; Three
- AAA; BBB; CCC

This is to be equivalent with:

- #taglist([One; Two; Three])
- #taglist([AAA; BBB; CCC])

And eventually:

- #strong([One]), #strong([Two]), #strong([Three])
- #strong([AAA]), #strong([BBB]), #strong([CCC])

Unfortunately, this only works halfway. The bullet point list has now been cancelled.

2

The show rule is currently returning the modified it.body which is no longer an enum.item.

Returning the correct thing:

#let taglist(content) = {
  let tags = content.text
    .split(";")
    .map(str.trim)
    .filter(s => s != "")

  tags.map(t => strong(t)).join(", ")
}

#show list.item: it => {
    enum.item(taglist(it.body))//small change here
}

- One; Two; Three
- AAA; BBB; CCC

image

3

Thank you for your reply. Unfortunately, your answer refers to a numbered list. I would like to have a list with bullet points.

4

Sorry about that!
In theory it would be as simple as changing it from enum.item to list.item but then the show rule applies to the already modified item. So this will first check if there is a semicolon before modifying it. If there is no semicolon it will simply return what it found (it).

#show list.item: it => {
  if it.body.func() == text and it.body.fields().text.contains(";"){
    list.item(taglist(it.body)) 
  } else {
    it
  }
}

If you are using semicolons in your lists for other things you may need to make further changes to the code (maybe attaching a label to all modified items and checking for labels before applying the show rule).

Full Code 
#let taglist(content) = {
  let fields = content.fields().text
  let tags = fields
    .split(";")
    .map(str.trim)
    .filter(s => s != "")

  tags.map(t => strong(t)).join(", ")
}

#show list.item: it => {
  if it.body.func() == text and it.body.fields().text.contains(";"){
    list.item(taglist(it.body)) 
  } else {
    it
  }
}

- One; Two; Three
- AAA; BBB; CCC
- This doesn't have a semicolon
- This does; So it gets treated differently

image

5

Where did you get this information? Is there a detailed documentation somewhere regarding list.item and list.item.body? It’s a bit thin: Bullet List Function – Typst Documentation

6

Mostly I just fumbled around inside the show function. By hovering the mouse over a variable, you can see all the values it has in the document. This let me find out what properties and methods were available (and their values) for a list item.

Also, it turns out that solution is actually very fragile:

- 1; 2
- 1;2
- _1_; 2
- 1 ; 2
- 1; _2_

image

Changing to nested show rules like this is much more robust. The only downside I know of right now is that, unlike your example from the original post, this one also applies strong to the commas (,).

#show list.item: it => {
  show regex(".*;.*"): it => {
    show regex("\s*;\s*"): ", "
    strong(it)
  }
  it
}

- 1; 2
- 1;2
- _1_; 2
- 1 ; 2
- 1; _2_
- One; Two; Three
- AAA; BBB; CCC
- This doesn't have a semicolon
- This does; So it gets treated differently
Output

image

1 Like
7

Are you working with the web editor or with another editor (e.g. Visual Studio Code)?

8

For this, the web editor. I also use VSCodium (basically VSCode) with tinymist, and the “hover over to see the values” works in both.

9

I have created something that works for me. I used a trick that I copied from typst-chep. To ensure that the show rule is only applied once, I use a content element as a marker. After the show rule has been applied, the marker is removed and the show rule is not applied again.

Next, I filter out all elements that I cannot convert into text (e.g. spaces). I then join the remaining elements together.

#let taglist(text) = {
  let tags = text
    .split(";")
    .map(str.trim)
    .filter(s => s != "")

  tags.map(t => strong(t)).join(", ")
}

#show list.item: it => {
  if not (type(it.body) == content and it.body.func() == [].func()) {
    return it
  }
  let children = it.body.children

  if children.at(0) != [#"["] or children.at(1) != [#"TL"] or children.at(2) != [#"]"] {
    return it
  }
  
  let c = children.slice(4)
    .filter(i => i.func() == text)
    .map(i => i.text)
    .join()

  list(taglist(c))
}

- [TL] Hello
- [TL] One; Two
- [TL] AAA; BBB ; CCC;