Roles with data / parameters

[rowanc1]

I am wondering what the best way to add roles that have multiple attributes that need to be set, but no content. For example, creating a simple example for reactive document like (variables, displays and sliders):

# Hello World

```{variable}
:name: x
:value: 2
```

The value of x is {display}`value:x format:.1f`.

{range}`value:x min:0 max:10`

I am looking to suggest a format for the internals of a role, which I don't think are suggested at all by MyST.

Something like: attribute:value attribute2:value2?

I think the only overlap in functionality would be the glue role, but I don't think it has any arguments at the moment?

[choldgraf]

That's a great question - I feel like this one we should make sure to get everybody's input on, and then agree on a standard for all of the EBP roles. @chrisjsewell @AakashGfude @mmcky what do you think?

(I also renamed the issue to include the word "parameters" because I think this fits in a similar category)

[AakashGfude]

To add to this issue. Roles with multiple attributes that also have content , is also a necessary feature to have. As indicated by @choldgraf in this PR jupyter-book/jupyter-book#837

I thnk in rst, it is achieved by declaring it beforehand to create specialized roles? :- https://docutils.sourceforge.io/docs/ref/rst/roles.html#specialized-roles

[chrisjsewell]

Linking executablebooks/MyST-Parser#69

[choldgraf]

oi I can't believe it's been 6 months since those conversations, I totally forgot about that issue.

Looking through the ideas there, what about something like:

• {role}`content <option option key=val key="val w spaces">`

And have anything in < > parsed like a Python function would parse its inputs?

It piggy-backs on the current rST convention of < > to define a link. More generally, do we like the idea of having some kind of syntax to explicitly separate the "content" parts of the role from the "options" part of the role? (above, it is < > but could be something else like || or something)