<i18n dev> Possible error in tr18?

Tom Christiansen tchrist at perl.com
Wed Jan 26 12:10:20 PST 2011

Under the RL2.2 link of tr18, there appears to be a error:

    C2. An implementation claiming conformance to Level 2 of this
	specification shall satisfy C1, and meet the requirements 
	described in the following sections:

	RL2.1 Canonical Equivalents
	RL2.2 Extended Grapheme Clusters
	RL2.3 Default Word Boundaries
	RL2.4 Default Loose Matches
	RL2.5 Name Properties
	RL2.6 Wildcards in Property Values

Following the RL2.2 link, you find this:

    2.2 Extended Grapheme Clusters

    One or more Unicode characters may make up what the user thinks of as a
    character. To avoid ambiguity with the computer use of the term character,
    this is called a grapheme cluster. For example, "G" + acute-accent is a
    grapheme cluster: it is thought of as a single character by users, yet is
    actually represented by two Unicode characters. The Unicode Standard
    defines extended grapheme clusters that keep Hangul syllables together and
    do not break between base characters and combining marks. The precise
    definition is in UTR #29: Text Boundaries [UAX29]. These extended grapheme
    clusters are not the same as tailored grapheme clusters, which are covered
    in Level 3, Tailored Grapheme Clusters.

      RL3.12 Extended Grapheme Clusters

      To meet this requirement, an implementation shall provide a mechanism
      for matching against an arbitrary extended grapheme cluster, a literal
      cluster, and matching extended grapheme cluster boundaries.

Do you guys imagine that that should be "RL2.2" there instead of "RL3.12"?

Why should RL2.2 -> 2.2 -> RL3.12?  Or is that actually talking about 
tailored grapheme clusters?  I can't tell.


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