From: Shriramana Sharma <samjnaa_at_gmail.com>

Date: Thu, 12 Jul 2012 07:08:44 +0530

Date: Thu, 12 Jul 2012 07:08:44 +0530

Looking at the two sets of Brahmi numbers would also be instructive...

Sent from my Android phone

On Jul 12, 2012 6:21 AM, "Richard Wordingham" <

richard.wordingham_at_ntlworld.com> wrote:

*> What is a number having a numeric type of "digit" meant to convey?
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*>
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*> The old Unicode 2.0 definition definition of "digit value" seemed clear:
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*> "Digit value. This is a numeric field. If the character represents a
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*> digit, not necessarily a decimal digit, the value is here. This covers
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*> digits which do not form decimal radix forms, such as the compatibility
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*> superscript digits. This field is informative."
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*>
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*> That definition seems to be gone. From what we now have, I can think
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*> of several meanings, e.g.:
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*>
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*> 1) It's a digit in a system of decimal place notation, but doesn't quite
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*> qualify for some reason. Typical examples are:
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*>
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*> a) U+19DA NEW TAI LUE THAM DIGIT ONE - cruelly denied "decimal" status
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*> because it wasn't assigned with 9 clones of the other Tai Lue digits.
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*>
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*> b) U+2070 SUPERSCRIPT ZERO - not in a contiguous range, and
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*> apparently possibility of misleading parsers
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*>
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*> c) U+2080 SUBSCRIPT ZERO - apparent possibility of misleading parsers
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*>
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*> 2) It's in a decimal system, but not with place notation:
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*>
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*> a) U+10E60 RUMI DIGIT ONE. By contrast U+10E69 RUMI NUMBER
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*> TEN is a mere "numeric" - possibly because numeric field values of
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*> blank for decimal digit value (field 6 in UnicodeData.txt), 1 as the
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*> digit value (field 7) and 10 as the value (field 8) would be too
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*> confusing, as well as contrary to the current rules.
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*>
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*> On the other hand, I don't see why, apart from a general disapproval of
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*> compatibility characters, the Roman numerals U+2170 SMALL ROMAN
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*> NUMERAL ONE to U+2178 SMALL ROMAN NUMERAL NINE don't count as digits.
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*>
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*> 3) It's derived from a decimal digit, e.g. U+2468 CIRCLED DIGIT
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*> NINE is "digit", whereas the next in the series, U+2469 CIRCLED NUMBER
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*> TEN, just has a numeric type of "numeric".
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*>
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*> ----
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*>
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*> It's not clear to me why the following decimal digits (in the normal,
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*> not the Unicode sense) are not classified as "digit" but just as numeric
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*>
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*> U+1D360 COUNTING ROD UNIT DIGIT ONE
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*> U+3021 HANGZHOU NUMERAL ONE
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*>
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*> The only reason for U+1D369 COUNTING ROD TENS DIGIT ONE not to be a
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*> digit that I can think of is that the system is conceived of as a
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*> centesimal system. The counting rods 'UNIT' and 'TENS' digits are used
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*> alternatively to avoid misreading, with various methods
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*> for indicating zero.
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*>
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*> Likewise, why are U+0C79 TELUGU FRACTION DIGIT ONE FOR ODD POWERS OF
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*> FOUR and related characters not digits? Is it because they are a base
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*> 4 (or collectively hexadecimal) system?
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*>
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*> Perhaps some light can be shed on the system by learning what people
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*> actually use the numeric types and (decimal) digit values for.
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*>
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*> Richard.
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*>
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*>
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Received on Wed Jul 11 2012 - 20:41:18 CDT

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