Re: [xml2rfc] [irsg] character sets, was UPDATE regarding <u>

[Carsten Bormann <[e-mail]>]

On 2023-03-04, at 20:03, John Levine <[e-mail]> wrote:
> 
> One issue is our policy about where any non-ASCII goes, but a separate
> issue that Carsten has run into is exotic characters beyond the 3000
> or so that are in the fonts we normally use.

Kramdown-rfc 1.6.26 now has an `echars` utility that is more talkative about unicode blocks and unicode scripts.  Examples below.  I hope this is useful in our quest to rescue these Unicode arcana from being held captive by Unicode super-geeks.

Grüße, Carsten


This is the RFC-to-be where RPC happened to pick a character from the Dingbats block that started this discussion:

$ echars rfc/authors/rfc9340.txt
*** Latin-1 Supplement (Latin)
ß: U+00DF    1 LATIN SMALL LETTER SHARP S
á: U+00E1    3 LATIN SMALL LETTER A WITH ACUTE
ä: U+00E4    1 LATIN SMALL LETTER A WITH DIAERESIS
é: U+00E9    5 LATIN SMALL LETTER E WITH ACUTE
ó: U+00F3    1 LATIN SMALL LETTER O WITH ACUTE
ø: U+00F8    1 LATIN SMALL LETTER O WITH STROKE
ü: U+00FC    7 LATIN SMALL LETTER U WITH DIAERESIS
*** Latin Extended-A (Latin)
ć: U+0107    2 LATIN SMALL LETTER C WITH ACUTE
č: U+010D    2 LATIN SMALL LETTER C WITH CARON
ę: U+0119    1 LATIN SMALL LETTER E WITH OGONEK
ł: U+0142    2 LATIN SMALL LETTER L WITH STROKE
š: U+0161    1 LATIN SMALL LETTER S WITH CARON
*** General Punctuation (Common)
–: U+2013    1 EN DASH
*** Dingbats (Common)
➔: U+2794    2 HEAVY WIDE-HEADED RIGHTWARDS ARROW
*** Miscellaneous Mathematical Symbols-A (Common)
⟩: U+27E9   61 MATHEMATICAL RIGHT ANGLE BRACKET
*** Arabic Presentation Forms-B (Common)
: U+FEFF    1 ZERO WIDTH NO-BREAK SPACE


For comparison, an RFC out of the pre-v3 times:

$ echars rfc/rfc8265.txt
*** Basic Latin (Common)
"\f": U+000C   25 <control-000C>
*** Latin-1 Supplement
¹: U+00B9    1 SUPERSCRIPT ONE (Common)
ß: U+00DF    3 LATIN SMALL LETTER SHARP S (Latin)
å: U+00E5    1 LATIN SMALL LETTER A WITH RING ABOVE (Latin)
*** Latin Extended-A (Latin)
ſ: U+017F    2 LATIN SMALL LETTER LONG S
*** Greek and Coptic (Greek)
Σ: U+03A3    2 GREEK CAPITAL LETTER SIGMA
π: U+03C0    2 GREEK SMALL LETTER PI
ς: U+03C2    2 GREEK SMALL LETTER FINAL SIGMA
σ: U+03C3    2 GREEK SMALL LETTER SIGMA
*** Ogham (Ogham)
 : U+1680    1 OGHAM SPACE MARK
*** Number Forms (Latin)
Ⅳ: U+2163    6 ROMAN NUMERAL FOUR
*** Mathematical Operators (Common)
∞: U+221E    2 INFINITY
*** Miscellaneous Symbols (Common)
♦: U+2666    1 BLACK DIAMOND SUIT
*** Alphabetic Presentation Forms (Latin)
fi: U+FB01    2 LATIN SMALL LIGATURE FI
*** Arabic Presentation Forms-B (Common)
: U+FEFF    1 ZERO WIDTH NO-BREAK SPACE

You can see the form feeds we used before RFC8650, as well as the dreadful BOM already (which is in the Arabic Presentation Forms-B block, in case you didn’t know that).