# RE: numeric properties of Nl characters in the UCD

Date: Thu Nov 27 2003 - 05:24:11 EST

• Next message: Arcane Jill: "RE: numeric properties of Nl characters in the UCD"

Arcane Jill writes:
> ...which brings me back to my question (which no-one's answered yet).
> What do the properties "digit" versus "decimal digit" actually MEAN? Is
> it possible for someone to give a PRECISE definition. I mean, it seems
> pretty clear that "decimal digit" does NOT mean "radix ten digit"
> (otherwise circled digit 2 would be a "decimal digit", and it isn't). I
> can only assume that the INTENDED meaning of what is (erroneously?)
> called "decimal digit" is "a character which is permitted to play a part
> in a positional number system" - thus "2" is a decimal digit because it
> can form part of the legal number "123", but circled digit 2 is not
> because "1?3" is not a legal number. Am I even close?

Look in the public review page http://www.unicode.org/review/
for the proposed new changes notably:

26 Update properties for Ethiopic and Tamil non-decimal digits
2003.01.27 Decimal numbers are those using in decimal-radix
number systems. In particular, the sequence of the ONE character
followed by the TWO character is interpreted as having the value
of twelve. We have gotten feedback that this is the not the case
for Ethiopic or Tamil. Details are
on the public issues page.

This is related to the definition of decimal digits...
So a decimal digit property should mean that the character is usable in a
positional system to compose numbers with a radix 10.

Circled digits don't have a "decimal digit" property because they are not
composable to create numbers in a positional system (either left-to-right
or right-to-left). But may be they could if one used ligatures like:
<CIRCLED DIGIT NINE, ZWJ, CIRCLED DIGIT TWO> to create an abstract
character <CIRCLED NUMBER NINETY TWO>. How it will be rendered is another
problem, but the need to use a control format with such private encoding
convention will still prohibit the character to be assigned a general
purpose decimal property.

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