So, right now, when you have something like 100% + 2em + 2pt, internally that's somewhat divided between a relative part (100%) and an absolute part (2em + 2pt). Likewise, for strokes, you have something like 2pt + blue, which is divided between thickness (2pt) and color (blue). Right now, to perform this separation in typst, using regex with repr and eval is necessary. I think this indicates to me that this should definitely be a built-in feature to avoid that hassle. Maybe we could use some notation like stroke.thickness(2em + blue), which returns 2em; or stroke.thickness(2pt) which will return 2pt; or stroke.color(2pt + red) which will return red; and so on. Same for relative lengths - something (maybe?) like length.relative(50% + 2pt) returning 50%; length.absolute(60% + 4pt) returning 4pt, and so on. Of course, that notation can vary (personally, I think the stroke one is fine, but the length one could be made better, perhaps). I could perhaps attempt to eventually PR this depending on what is suggested here. Thoughts?