Definition of Values of Property Vertical_Orientation

Asmus Freytag asmusf at
Tue Aug 23 07:36:22 CDT 2022

On 8/22/2022 3:45 PM, Richard Wordingham via Unicode wrote:
> But "U+0023 NUMBER SIGN ("#") is used to indicate comments: all
> characters from the number sign to the end of the line are considered
> part of the comment, and are disregarded when parsing data."
> and "The comments are purely informational, and may change format or be
> omitted in the future. They should not be parsed for
> content."!(Revision 28 Section 4.2.4).
> I think something needs to be added at the start of Section 4.2.4 to say
> that a line starting U+0023, U+0020, U+0040 is exceptionally*not*  a
> comment line.

That the @missing directives are contained in comment lines is a 
long-standing issue.

Indeed, section 4.2.10 starts (emphasis added):

            4.2.10 @missing Conventions

    Specially-formatted /*comment lines*/ with the keyword "@missing"
    are used to define default property values for ranges of code points
    not explicitly listed in a data file. These lines follow regular
    conventions that make them machine-readable.

    An @missing line /*starts with the comment character "#", followed
    by a space, then the "@missing" keyword*/, followed by a colon,
    another space, a code point range, and a semicolon. Then the line
    typically continues with a semicolon-delimited list of one or more
    default property values. For example:

        # @missing: 0000..10FFFF; Unknown

I see no reason to add anything to section 4.2.4 other than, perhaps, a 
note that points to section 4.2.10 from the bullet item you cite.

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