More sort suggestions

[Charlie Gordon]

Another idea for sort I've been toying with in my own utilities : natural
order.
It is basically lexico-graphical order, locale specific or not, with one
departure when encountering digits.
strings that compare equal upto a substring of digits [0-9]+ are then
compared as if -n and back to lexicographical if numbers compare equal.  A
simple implementation follows:

int natcmp(const char *s1, const char *s2)
{
     while (*s1) {
        if (isdigit(*s1) && isdigit(*s2)) {
            unsigned long n1 = strtoul(s1, &s1, 10);
            unsigned long n2 = strtoul(s2, &s2, 10);
            if (n1 == n2)
                continue;
            return (n1 < n2) ? -1 : 1;
        }
        if (*s1 != *s2)
             break;
        s1++;
        s2++;
    }
    return (*s1 < *s2) ? -1 : (*s1 != *s2);
}

This allows sorting chapter files in a more human friendly order
Take a shot at `infocmp xterm` and look at the order for function key
escapes (kf*=)

Is this implemented anywhere un textutils or core-utils ?
Does it belong here ?
How about an option in /bin/ls ?

Charlie Gordon.