The Unicode Technical Committee is considering giving a number of additional characters the Deprecated property.
The
Deprecated property means that the use of the character is discouraged,
and provides a machine-readable table for implementations. However,
there are a number of characters that are marked as "discouraged"
either in the text of the standard or in the names list, so the goal is
to either add them to the set of characters with the Deprecated
property, or if there is good reason not to, then remove the phrasing
about their being discouraged. These are listed below in Table 1.
Table
2 provides additional characters that various people have proposed for
Deprecation when this topic was discussed in the UTC. Table 3 gives the
characters deprecated in U5.1, for comparison.
As part of this proposal, we would add text that makes the following points more clearly.
Deprecated does not mean removed, just discouraged -- one could still get them from character encoding converters, for example.
Whenever
implementations require roundtripping to legacy encodings, deprecated
characters should not be transformed or filtered -- the same as with
normalization, especially NFKC.
In
other circumstances, deprecated characters should be avoided where
possible. Where there is a preferred alternative, it should be used
instead. That is generally a normalized form, but not always (see
below).
Certain characters cannot
occur at all in text that is in normalization form NFC. This
effectively discourages the use of those characters, but does not
formally constitute deprecation, nor does this PRI suggest that they
all be given the Deprecated property. For reference, there is a link to the
list of those characters below.
The UTC would appreciate feedback on this proposal.
The preferred forms for these are:
U+27E8 ( ⟨ ) MATHEMATICAL LEFT ANGLE BRACKET
U+27E9 ( ⟩ ) MATHEMATICAL RIGHT ANGLE BRACKET
while the NFC and NFKC forms are:
U+3008 ( 〈 ) LEFT ANGLE BRACKET
U+3009 ( 〉 ) RIGHT ANGLE BRACKET
0149 ( ʼn ) LATIN SMALL LETTER N PRECEDED BY APOSTROPHE **
The
preferred form is 'n or ’n (with U+2019): this is but one of many such
abbreviations in Dutch and Afrikaans, all of which are represented with
apostrophe plus letter. The NFKC form does not match this preferred
form, having U+02BC ( ʼ ) MODIFIER LETTER APOSTROPHE.
