scriptlevel and displaystyle

[davidcarlisle]

https://w3c.github.io/mathml/#presm_scriptlevel

says of scriptlevel and displaystyle attributes:

They also may be set explicitly via the displaystyle and scriptlevel attributes on the mstyle element or the displaystyle attribute of mtable. In all other cases, they are inherited from the node's parent.

similarly the schema "adds" these to <mstyle>

https://w3c.github.io/mathml/#parsing_mstyle.specificattributes

and mstyle attribute table lists them:

https://w3c.github.io/mathml/#presm_mstyle_attrs

However all these descriptions come from Mathml3.

Core makes them global

https://w3c.github.io/mathml-core/#global-attributes

so in Full they are common to all Presentation elements.

https://w3c.github.io/mathml/#presm_presatt

So should not be described as specific to mstyle.

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This is assuming we are happy to relax the use of scriptlevel in this way. (I do not recall why it was restricted in earlier versions).

If instead we want to keep the restriction, then the most natural place to do that would be to change Core so these are not global attributes there, but keeping Core as it is, and changing Full to match looks OK to me.

[NSoiffer]

I think the reason to avoid them on all elements was because that we didn't need to think about how they interreacted with an element that changed the scriptlevel. Putting all that logic on/isolating it to mstyle seemed easiest for the spec and implementations.

It seems safe to change them to be global, but we need to say that the new value overrides the existing value on the current element, not on the any children that change it (they make use of the new value as part of their changes).