Reserved general punctuation

Paul Hoffman phoffman at
Wed Apr 30 22:53:37 CEST 2008

At 1:38 PM -0700 4/30/08, Mark Davis wrote:
>It *is* related to Noncharacters. Default_Ignorable_Code_Point is a 
>derived property. The code points that are unassigned (gc=Cn) but 
>that should be DISALLOWED are all and only the Noncharacters.

Then I'm really confused. From the new draft:

2.1.3.  IgnorableProperties (C)

    C: property(cp) is in {Default_Ignorable_Code_Point, White_Space,

    This category is used to group codepoints that are not recommended
    for use in identifiers.  In general, these codepoints are not
    suitable for use for IDN.

    The definition for Default_Ignorable_Code_Point can be found in
    DerivedCoreProperties.txt [1] (and erratum of 2007-January-25 [2])
    and is

    Other_Default_Ignorable_Code_Point + Cf + Cc + Cs
    + Noncharacter_Code_Point + Variation_Selector
    - White_Space - FFF9..FFFB (Annotation Characters)

Why have what whole list of things for "Default_Ignorable_Code_Point" 
if all we want is Noncharacter_Code_Point, which is already in the 
list for C? Why not have it at all?

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