L2/11-268

Title:  Bidi_Class Defaults for 08A0..08FF Arabic Extended-A Block

Date:   July 11, 2011

Source: Ken Whistler

Action: For consideration by the UTC


The assignment of a new extended Arabic block in the range 08A0..08FF
for Unicode 6.1 means that the UTC needs to adjust the Bidi_Class
defaults for that range.

Currently, as documented in DerivedBidiClass.txt:

# The unassigned code points that default to R are in the ranges:
# [\u0590-\u05FF \u07C0-\u08FF \uFB1D-\uFB4F \U00010800-\U00010FFF \U0001E800-\U0001EFFF]
#
# Hebrew: U+0590 - U+05FF
# NKo: U+07C0 - U+07FF
# Cypriot_Syllabary: U+10800 - U+1083F
# Phoenician: U+10900 - U+1091F
# Lydian: U+10920 - U+1093F
# Kharoshthi: U+10A00 - U+10A5F
# and any others in the ranges:
# U+0800 - U+08FF,
# U+FB1D - U+FB4F,
# U+10840 - U+10FFF,
# U+1E800 - U+1EFFF

However, the practice has been to default all unassigned code points in *Arabic*
blocks to AL, instead of R.

Therefore, the default for the range U+08A0..U+08FF needs to be changed to AL,
and the appropriate updates should be made to the text documenting these
ranges in DerivedBidiClass.txt for Unicode 6.1 as well.