bug#51011: [GNU sort] Numerical sort with delimiter may be broken (bug)

[Paul Eggert]

On 10/9/21 5:00 AM, Pádraig Brady wrote:
> On 09/10/2021 04:48, Paul Eggert wrote:

> > 'sort' could determine the group sizes from the locale, and
> > reject digit strings that are formatted improperly according to the
> > group-size rules. (Not that I plan to write the code to do that....)
>
> Yes I agree that would be better, but not worth it I think
> as there would still be ambiguity in what was a grouping char
> and what was a field separator. Also that ambiguity would
> now vary across locales.

I don't see the ambiguity problem. The field separator is used to 
identify fields; once the fields are identified, the thousands 
separator, decimal point, etc. contribute to numeric comparison in the 
usual way. So it's OK (albeit confusing) for the field separator to be 
'.' or ',' or '-' or '0' or any another character that could be part of 
a number.

For example, with 'sort -t 0 -k 2,2n', the digit 0 is not part of the 
numeric field that is compared, and there's no ambiguity about that even 
though 0 is allowed in numbers. The same idea applies to 'sort -t , -k 
2,2n'.