[css-values-5] Normalized attr() substitution value

[andruud]

What do you get if you serialize the computed value of --x here?

<div data-x="calc(1px + 2px)">

div { --x: attr(data-x length); }

I think we expect eager simplification (3px), and generally we may need something like the equivalent token sequence (but for non-computed values)?

[andruud]

OK, I now see the attribute value needs to be a single token (surprising), which means the example in the first post was bad.

In that case, what about:

<div data-x="10.000px">

div { --x: attr(data-x length); }

Does this serialize as 10px or 10.000px?