[css-anchor-position] Rename anchor-default to position-anchor

[tabatkins]

As the spec has sprouted more properties, a nice naming division has developed - all the props applying to the positioned element start with position-*, while the ones applying to the anchor element start with anchor-*. The obvious exception to this scheme is anchor-default, which is set on the positioned element. The Apple exploration renamed anchor-default to position-anchor, which is a pretty reasonable name.

This also opens up the possibility of using position to shorthand the positioning scheme (position-type: static | relative | etc) and the default anchor (position-anchor: --foo), as the Apple exploration suggested.

[kizu]

Sounds good, maybe the only thing to think about: how will this play with the position-container (#9868), as both might potentially be dashed idents, and if we'd want to have both in the shorthand, how to differentiate between them?

[css-meeting-bot]

The CSS Working Group just discussed [css-anchor-position] Rename `anchor-default` to `position-anchor` , and agreed to the following:

• RESOLVED: rename anchor-default to position-anchor
• ACTION Tab: open a new issue about resetting of position shorthand

The full IRC log of that discussion

<dbaron> TabAtkins: We've set up a dichotomy in names for properties: the things that apply to positioned element start with position-*, the things that apply to the anchor start with anchor-*. anchor-default is the exception.
<dbaron> TabAtkins: so for better consistency and easier author handling of the mental model, we want to shift its name. The name from the Apple proposal was position-anchor.
<fantasai> +1
<kizu> q+
<dbaron> TabAtkins: so proposal is to rename anchor-default to position-anchor and leave everything else the same
<astearns> ack kizu
<dbaron> kizu: as I mentioned in issue 30 mins ago, small issue is we have another proposal for position-container, which could potentially accept dashed ident. If both end up in shorthand for position there's a clash of 2 dashed idents. Otherwise seems like a good thing.
<astearns> ack fantasai
<dbaron> TabAtkins: we don't have a proposal for making a position shortand (yet), so I'm happy to leave that as a problem for future Tab to solve
<dbaron> fantasai: we should resolve whether or not the position property resets this
<dbaron> fantasai: that determines whether it could be in the shorthand in the future
<dbaron> fantasai: I think we should.
<dbaron> fantasai: In terms of shorthand syntax, we could use slashes to disambiguate, like we have in background shorthand.
<dbaron> TabAtkins: but position shorthand is a separate issue, we can resolve on the naming change first.
<dbaron> fantasai: I think we should decide whether it's reset by position.
<dbaron> TabAtkins: whether it's reset by the position shorthand won't changed based on what my call it.
<dbaron> fantasai: more or less natural based on name
<dbaron> TabAtkins: I'm trying to make incremental progress.
<dbaron> fantasai: then we definitely need a fololwup issue
<dbaron> Proposed resolution: rename anchor-default to position-anchor
<dbaron> RESOLVED: rename anchor-default to position-anchor
<dbaron> ACTION Tab: open a new issue about resetting of position shorthand