Definition of Values of Property Vertical_Orientation

[Richard Wordingham]

I've just spent a painful time verifying the loading of the values of
Vertical_Orientation.  After the list of codepoints and ranges in the
comments of VerticalOrientation.txt for which the value defaults to
Upright, is there any reason for having the ominous wording

"All other code points, assigned and unassigned, that are not listed
explicitly in the data section of this file are given the value R."

Given the current (Version 14.0) and candidate (Version 15.0) data
sections, is there any reason for not having the more reassuring

"All code points, assigned and unassigned, that are not listed
explicitly in the data section of this file are given the value R."

One could then set up the default value of the property as Rotated and
then just read in the data section as overrides, as with other files
just defining the value of one enumeration property.  As things stand,
loading the property values into an application involves three steps:

1) Set up the default value.
2) Set up the default values for the Upright regions listed in the
comments.
3) Set up the explicit values from the data file.

Given the current explicit data, Step 2 is redundant.

Richard.