[css-typed-om] "Create a CSSUnitValue from a string" invents its own CSS parsing

[dbaron]

The definition of create a CSSUnitValue from a string says:

To create a CSSUnitValue from a string str, return a new CSSUnitValue object with its value internal slot set to the numeric portion of str parsed into a number, and its unit internal slot set to the unit portion of str, or "number" or "percent" if str is a plain number or percent.

This seems to be inventing its own CSS parsing, and does it in a rather vague way (for example, what's a "numeric portion" -- does it support scientific notation?). It seems like it would be better to depend on the way CSS already parses dimensions.

[tabatkins]

That's solely an internal algorithm, used to make it much more convenient to create numeric values inline in an algorithm. (Currently only used in one place, but I expect it will see more use as we make more of them.)

[tabatkins]

It might be worth making it more explicitly take two values, a number and a unit. Hm.

[nainar]

Yes, I think it would easier to have the following two ways of constructing CSSUnitValues:

• double value, string unit
• string value, string unit