Math layout: Don’t add frames for MetaElems

[bluebear94]

See #3727

The tests still pass, but this is probably not the correct solution. Wondering if there’s another way to fix this.

[laurmaedje]

This will indeed break introspection in math, e.g.:

$ #metadata("hi") $
#context query(metadata)

To fix it properly, MetaElem::data probably needs to be handled in better non-frame way by the math layout.

[bluebear94]

For some reason, $ a class("relation", "--") #metadata("hi") b $ also produces incorrect spacing in the current development version (though not in 0.11). I think it has to do with removing the custom Behaved implementation from MetadataElem.

[bluebear94]

Also, Content::layout_math flattens nested sequence elements, but it can’t see through realization steps (context blocks, Show implementations). I wonder if a more general solution is needed, perhaps assigning a behavior to each MathFragment.

[laurmaedje]

For some reason, $ a class("relation", "--") #metadata("hi") b $ also produces incorrect spacing in the current development version (though not in 0.11). I think it has to do with removing the custom Behaved implementation from MetadataElem.

That's more a bug with math than with the Behaved implementation. The whole math thing is all just approximate pseudo-realization. I'm trying to also unify the math realization with the proper one as part of the realization improvements.

[bluebear94]

Fair enough; do you want to close this for now since the underlying issue would be solved by unifying math realization with the proper one?

[laurmaedje]

Yeah, let's close this for now.