Is the a style category for horizontal dividers?

[jodros]

The goal is to change the before/after skips.

[Omikhleia]

There's already so many ways it can be achieved with custom styles, that I am unsure we need a predefined style here.

Say, add this in your style file:

MyDivider:
  style:
    paragraph:
      after:
        skip: "1cm"
      before:
        skip: "1cm"
      align: "center"

Then:

## Normal divider

Lorem...

---

Lorem...

## Custom-styled div with inside divider

Lorem...

{custom-style="MyDivider"}
:::
---
:::

Lorem...

## Custom-styled divider via symbol shortcut

[^:---divider---:]: {custom-style="MyDivider"}
  :::
  ---
  :::

Lorem...

:---divider---:

Ipsum...

## Custom-styled divider via symbol registration

```=sile-lua
-- Of course one would put that in a class or package ideally
local self = SILE.documentState.documentClass
self.packages["markdown.commands"]:registerSymbol("---other---", true, function (opts)
    return {
      SU.ast.createCommand("style:apply:paragraph", { name = "MyDivider" }, {
        "• • • • • •"
      })
    }
end)
```

Lorem...

:---other---:

Lorem...

Each technique has pros and cons

• (2) is quite direct for one casual use, but a bit cumbersome if repeated a lot.
• (3) is the same shortcut idea as in How to add new horizontal dividers? markdown.sile#136 (comment) but it's only valid in a given document, so you'd have to repeat it in other documents.
• (4) shows programmatic symbol registration, and once registered it's available in all documents. It requires some Lua code somewhere, though ;)

BTW, there's a small bug somewhere, the "div" wrapping in (2) and (3) should not have been necessary i.e. the following should have worked:

{custom-style="MyDivider"}
---

Feel free to open a bug on markdown.sile, and perhaps analyse what I missed there and submit a PR for it ;-)