Date

L2/08-018

Date: 9 Jan 2008
Source: Mark Davis
Subject: Deprecated Characters (Post 5.1)

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I was weeding through and cleaning up some papers and came across some notes I made on

http://www.unicode.org/L2/L2006/06344-dep-chars.txt

There were no actions or decisions taken at the relevant UTC meeting, but Ken had the note "Mark will follow up, but no decision taken."

Here is a followup.

My notes from the meeting were:

Put together ad-hoc to review and come up with list.
Add:
- 0149( ŉ ) LATIN SMALL LETTER N PRECEDED BY APOSTROPHE
- 0953 ( ॓ ) DEVANAGARI GRAVE ACCENT
- 0954 ( ॔ ) DEVANAGARI ACUTE ACCENT
Give guidelines and criteria for deprecation.
Document why each character (or set of related characters) is deprecated.
In particular, what should implementations do with deprecated characters?
- substitute if possible
- otherwise avoid if possible (but don't remove)
Document that NFC (and to a lesser degree, NFKC) effectively discourages singletons, & certain others, so they are effectively deprecated.

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Note: The items in 06-344 plus other possible items are
[\u212A\u0953\u0954\u17A3

\u17A4\u17D8 \u0F07\u0149\u037E\u0387\u0344\u0344 \u0F73\u0F75\u0F77\u0F79\u0F81 \u17D3\u17D8\u2329\u232A \u2126\u20A4\u212B]

I just now quickly ran them through the unicode utilities ( http://unicode.org/cldr/utility/list-unicodeset.jsp), and here is a breakdown for further discussion. I suggest we have an ad hoc at the UTC to consider these and decide which are candidates for deprecation (post 5.1). (There may also be future candiates, so we might continue the ad hoc in future meetings.)

Allowed by NFKC:

( ॓ ) DEVANAGARI GRAVE ACCENT

( ॔ ) DEVANAGARI ACUTE ACCENT


		
		0F07

( ༇ ) TIBETAN MARK YIG MGO TSHEG SHAD MA


		
		17A3

( ឣ ) KHMER INDEPENDENT VOWEL QAQ


		
		17A4

( ឤ ) KHMER INDEPENDENT VOWEL QAA


		
		17D3

( ៓ ) KHMER SIGN BATHAMASAT


		
		17D8

( ៘ ) KHMER SIGN BEYYAL


		
		20A4

( ₤ ) LIRA SIGN

Allowed by NFC (in addition to above):

( ŉ ) LATIN SMALL LETTER N PRECEDED BY APOSTROPHE


		
		0F77

( ཷ ) TIBETAN VOWEL SIGN VOCALIC RR


		
		0F79

( ཹ ) TIBETAN VOWEL SIGN VOCALIC LL

Other (effectively deprecated by NFC):

( ̈́ ) COMBINING GREEK DIALYTIKA TONOS


		
		037E

( ; ) GREEK QUESTION MARK

( · ) GREEK ANO TELEIA


		
		0F73

( ཱི ) TIBETAN VOWEL SIGN II


		
		0F75

( ཱུ ) TIBETAN VOWEL SIGN UU


		
		0F81

( ཱྀ ) TIBETAN VOWEL SIGN REVERSED II

( Ω ) OHM SIGN


		
		212A

( K ) KELVIN SIGN


		
		212B

( Å ) ANGSTROM SIGN

( 〈 ) LEFT-POINTING ANGLE BRACKET


		
		232A

( 〉 ) RIGHT-POINTING ANGLE BRACKET

The full list of characters disallowed by NFC are at:
http://unicode.org/cldr/utility/list-unicodeset.jsp?a=[:nfcquickcheck=no:]

And the additional characters disallowed by NFKC are at:
http://unicode.org/cldr/utility/list-unicodeset.jsp?a=[[:nfkcquickcheck=no:]-[:nfcquickcheck=no:]]