Re: [Groff] Question about .substring

[Ralph Corderoy]

Hi ulrich,

> >     -- Request: .substring str n1 [n2]
> >         Replace the string named STR with the substring defined by the
> >         indices N1 and N2.  The first character in the string has index 0.
> >         If N2 is omitted, it is taken to be equal to the string's length.
> 
> shouldn't that be "it is taken to be equal to the string's length - 1"
> ?  (As we count from zero.)

That's how substring_request() works it out.
http://git.savannah.gnu.org/cgit/groff.git/tree/src/roff/troff/input.cpp#n4777

      int end = -1;
      if (!has_arg() || get_integer(&end)) {
        ...
        if (start < 0)
          start += real_length;
        if (end < 0)
          end += real_length;
        if (start > end) {
          int tem = start;
          start = end;
          end = tem;
        }

"If N2 is omitted, the index of xx's last character is used."?

Cheers, Ralph.