bug#33205: 26.1; unibyte/multibyte missing in rx.el

["Mattias Engdegård" <mattiase@acm.org>]

7 nov. 2018 kl. 20.10 skrev Eli Zaretskii <eliz@gnu.org>:
>> Perhaps those char classes didn't see much use.
> 
> Definitely not.  I cannot even think of a practical use case for them
> nowadays.

But were they useful back then, when they were added? If so, for what? Maybe it's been lost in the mists of time.

> 
>> The old behaviour seems a little more intuitive, but it must be rare to need regex matching of rubbish bytes in multibyte strings. If you could argue that the status quo is fine then I wouldn't necessarily object, but would suggest that at least the code be made explicit about it (and the documentation, as well).
> 
> I can fix the docs, but I don't think I understand what would you like
> to do about the code.

If we are content with [:unibyte:]/[:multibyte:] = [:ascii:]/[:nonascii:], then it would be nice if the code were obvious about it. Right now, ISUNIBYTE and IS_REAL_ASCII differ, and it takes some digging to realise that they have the same effect. Removing RECC_UNIBYTE/RECC_MULTIBYTE entirely and use RECC_ASCII/RECC_NONASCII throughout would make the semantics clear.