Definition of Values of Property Vertical_Orientation

Sławomir Osipiuk sosipiuk at
Tue Aug 23 12:56:27 CDT 2022

On Tuesday, 23 August 2022, 13:29:42 (-04:00), Asmus Freytag wrote:

No, it does have complex "defaults" in the second sense of default (value 
for unassigned code point) but not for the first sense of default ("omitted 
value in the listing").

Excuse the pedantry, but I don't see how. If as you said earlier, "This 
range-based concept of defaults is what's called "complex" defaults", then 
Vertical_Orientation isn't complex because it *doesn't* have range-based 
defaults. It has one default only, and a bunch of explicit ranges 
(including both assigned and unassigned code points). That's what's in the 
data file.

You can say that *conceptually* unassigned code point ranges are given 
"default" values (that are actually explicit in the data file) but this 
invites confusion, as this whole thread indicates. If we are being given 
instructions on how to parse data, such descriptions are superfluous and 
make the programmer question what their responsibility is. Ordinary 
developers shouldn't need to understand every nuance and motivation of 
Unicode design, they just want to know how to Get It Right.

To a programmer, a complex default is something that *cannot* just be a 
single "else" value. For VO, that's coming in the next version, but it 
isn't here yet. Including it in was premature.
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