Why no non-latin TODIGIT mappings in UTF-8.src ?

[Wolfgang Zenker]

* Andrey Chernov <ache at freebsd.org> [070528 13:52]:
> On Mon, May 28, 2007 at 10:46:59AM +0200, Wolfgang Zenker wrote:
>> Looking at our UTF-8.src, I see

>> $ grep DIGIT UTF-8.src
>> DIGIT     '0' - '9'
>> XDIGIT    '0' - '9'  'A' - 'F'  'a' - 'f'
>> TODIGIT   < '0' - '9' : 0x0000 >
>> TODIGIT   < 'A' - 'F' : 10 > < 'a' - 'f' : 10 >

>> It appears to me that isdigit() behaviour is controlled by the DIGIT
>> keyword, not TODIGIT. However, I do admit that I don't understand completely
>> how locale files are supposed to work. So where does e.g. iswdigit() get
>> its character class information from, should that not be in the locale
>> information as well somewhere?

> There is no POSIX function to extract TODIGIT info, so it is useless for 
> now.

Ok, so the mklocale src files that DO provide additional TODIGIT mappings
(like e.g. am_ET.UTF-8.src or ja_JP.SJIS.src) do so just to be prepared
for the day we can use them?

> todigit() is SCO extension and its manpage says:
> The macro todigit returns the digit character corresponding to its integer 
> argument. The argument must be in the range 0-9, otherwise the behavior is 
> undefined.
> iswdigit() have the same 0-9 restriction as isdigit() just accepts wint_t

I had imagined that TODIGIT would be used for a locale-aware version of
digittoint(3) or something like that. What would be a good place to read
up about how much can be localised with locales and how much of it we
currently (and maybe in the near future) support?

Wolfgang