Subject: bug#16731: 24.3.50; Latin small letter sharp s is not considered lower-case

From: Andreas Röhler <[email-masked]>
Date: Wed, 12 Feb 2014 21:33:31 +0100

Am 12.02.2014 21:16, schrieb Eli Zaretskii:
>> Date: Wed, 12 Feb 2014 21:10:57 +0100
>> From: Andreas Röhler <[email-masked]>
>> CC: [email-masked]
>>
>> While upcase1 can't succeed, downcase should - if "ß" is a member of downcase_table.
>
> But which character do you want to downcase in this case?
>
> This whole logic works only for _pairs_ of characters (and the
> char-table used here is populated by calls to set-case-syntax-pair).

So populate it differently, resp. allow empty slots.

> Such machinery cannot possibly work when there's no pair.
>
> The only way I can see out of this conundrum is to consult the
> Lowercase Unicode property of the character as fallback, assuming that
> won't slow down regex search too much.
>
>

You can do (downcase "d") for example, which results in "d".

Instead of

upcase1 (c) != c

what about

downcase (c) == c

?