A left-flanking delimiter run is a delimiter run that is
(1) not followed by Unicode whitespace,
and either
(2a) not followed by a punctuation character,
or
(2b) followed by a punctuation character and preceded by Unicode whitespace or a punctuation character. (…)A right-flanking delimiter run is a delimiter run that is
(1) not preceded by Unicode whitespace,
and either
(2a) not preceded by a punctuation character,
or
(2b) preceded by a punctuation character and followed by Unicode whitespace or a punctuation character. (…)
A punctuation character is
an ASCII punctuation character or
anything in the general Unicode categoriesPc,Pd,Pe,Pf,Pi,Po, orPs.
Unicode Punctuation P character property (major category)
| Value | Category minor | Count (13.0) | Remarks |
|---|---|---|---|
Pc |
connector | 10 | Includes “_” underscore |
Pd |
dash | 25 | Includes several hyphen characters |
Ps |
open | 75 | Opening bracket characters |
Pe |
close | 73 | Closing bracket characters |
Pi |
initial quote | 12 | Opening quotation mark. Does not include the ASCII “neutral” quotation mark. May behave like Ps or Pe depending on usage |
Pf |
final quote | 10 | Closing quotation mark. May behave like Ps or Pe depending on usage |
Po |
other | 593 |
Ideographic Full Stop 。 and Comma 、, U+3002 and U+3001, are both Po other.
The flanking behavior could respect the Unicode minor category more, but I donʼt think this would help in this particular case.