Asmus Freytag wrote:
Having Nd be limited to characters that
a) are used in decimal radix numbers
b) are part of a complete, ordered sequence 0..9
would make this property regular enough to serve
implementers. You could script the creation of
relevant data for your implementation based on that
property.
*Exceptions* exist and need to be documented.
Having exceptions machine readable is not as
important, but having implementers understand
them is.
Therefore, the best thing is for these to become
something other than Nd, but to retain their numeric
type of digit.
Together with a detailed explanation of each in
the appropriate script chapter, AND a complete
summary of all exceptional cases in a central
place (section 4.6 comes to mind) would provide
implementers with the information they need.
The exceptional cases that I'm aware of are
a) Arabic using two complete series of digits
b) New Thai Lue using an extra digit 1
c) Han digits being scattered and used in two
different types of numeric expressions
d) ASCII digits being used for some scripts
as preferred decimal-radix digits, because
their native number system is not, or not
exclusively decimal-radix
The above information belongs in section 4.6
in summary form, or simply as table of pointers
to each script chapter that contains a description
of unusual numeric behavior for decimal-radix
digits.
(A separate table pulling together all the descriptions
of non-decimal radix number systems that are
discussed in the Standard would equally be useful
for the readers).
A./
This sounds good to me.
