235	Proposed Update UTS #10, Unicode Collation Algorithm	2013.04.29
Status:	Closed
Originator:	UTC
Informal Discussion:	Unicode Mail List (Join)
Formal Feedback:	Contact Form
Resolution:	The UTS will be updated with final content and published.

Description of Issue:

Draft updated 2013-03-18. Some of the 3.x sections of UTS #10 were reordered for better flow. See the Modifications for details.

The Unicode Collation Algorithm has been modified for certain edge cases, in particular:

• The Variable-Weighting option IgnoreSP has been removed because it did not prove to be useful.
• The highest primary weights FFFD..FFFF have been reserved for special collation elements.
• The data files for the CLDR root collation will be published via CLDR releases rather than as a set of files (in CollationAuxiliary.zip) in the UCA data directory. See UTS #35: LDML: Collation, Section 2.1, Root Collation Data Files.
• For more details, see Modifications. In addition, there are a number of minor changes for clarity and consistency of the text.

The DUCET has also been modified, in particular:

• All digits map to collation elements with the default secondary weight (0020 in the DUCET, "<BASE>" in the ISO 14651 CTT) rather than script-specific secondary weights for non-ASCII digits.
• In expansions, trailing collation elements use regular tertiary weights rather than MAX = 1F. The MAX tertiary weight is not used any more in the DUCET.
• Fourth-level weights have been removed from the DUCET data file. (These have not been used by the UCA.)
• See the draft DUCET for UCA 6.3 here: http://www.unicode.org/Public/UCA/6.3.0/

 

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