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[Scheme-reports] char-numeric? and unicode "numeric" property
- To: Scheme-reports@x
- Subject: [Scheme-reports] char-numeric? and unicode "numeric" property
- From: Shiro Kawai <shiro.kawai@x>
- Date: Mon, 25 Apr 2011 11:16:08 -1000
Probably I'm overlooking something, and will appreciate if anyone can
In r7rs draft, char-numeric? is defined to return #t iff it is applied
to a character that
has the Unicode Numeric property. It is the same as r6rs, presumably
taken from it.
However, what exactly is the Unicode "Numeric" property? I could
find the definitions
of Alphabetic, Uppercase, Lowercase and White_Space, but not a binary "Numeric"
property in the current standard (Unicode 6.0,
The similar question was raised in r6rs-discuss, and it looked answered:
But the document pointed from it had been replaced and superseded by
TR44 shown above.
As suggested in the above mail I searched "numeric property" in TR44,
and I did found
a couple, but they are not about the "Numeric" property---whether to
tell a character has a
"Numeric" property or not---but rather mentioning the type of property values.
Each character does have Numeric_Type and Numeric_Value property. So it is fine
if I can say a character whose Numeric_Type is other than "None" is a "Numeric"
character, for example. But I'd like to see the definitive description.
I looked at older versions of Unicode. Until Unicode 3.0.1,
PropList.txt did list
"Numeric" characters. In 3.1.0's they were gone (or moved somewhere I
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