Re: String#upto edge case - empty string causes infinite loop

> -----Original Message-----
> From: Arnaud Bergeron [mailto:[e-mail]] 
> Sent: Wednesday, January 10, 2007 9:20 PM
> To: [e-mail]
> Subject: Re: String#upto edge case - empty string causes infinite loop

<snip>

> > I understand your point, but I could just as well argue 
> that there is 
> > no logical successor to an empty string, and therefore it's 
> a special 
> > case. Another point to consider is that, if we have "".succ return 
> > "0", we get this result from String#upto:
> 
> I think you missunderstood something.  I don't propose it 
> returns "0" but "\000" which the character with ASCII value 0 
> (i.e. NUL).  I agree it could be some other value, but why I 
> chose this one is because that is the string with the 
> "smallest" (as determined by <) value which is bigger than "".

Hm, I guess if I think about it as null rather than 0 it makes more
sense.
 
> > "".upto(2) => ["", "0", "1", "2"]
> >
> > Either approach feels more or less arbitrary. I vote to err on the 
> > side of caution and stick with my original patch. :)
> 
> I think this issue might not be as important as I let it show 
> because this is not common code.  I still feel that ("" < 
> "".succ) == false is wrong though.
> 
> However, if succ is not going to change, then it's better to 
> have your patch than nothing.
> 
> Last but not the least.  I realize I have not provided a 
> patch for my solution.  Well here it is:
> 
> --- string.c.orig	Wed Jan 10 22:52:14 2007
> +++ string.c	Wed Jan 10 23:18:12 2007
> @@ -1392,7 +1392,6 @@
> 
>      str = rb_str_new5(orig, RSTRING(orig)->ptr, RSTRING(orig)->len);
>      OBJ_INFECT(str, orig);
> -    if (RSTRING(str)->len == 0) return str;
> 
>      sbeg = RSTRING(str)->ptr; s = sbeg + RSTRING(str)->len - 1;

I guess either one works for me. I leave it to Matz to decide which he
prefers.

Regards,

Dan


This communication is the property of Qwest and may contain confidential or
privileged information. Unauthorized use of this communication is strictly 
prohibited and may be unlawful.  If you have received this communication 
in error, please immediately notify the sender by reply e-mail and destroy 
all copies of the communication and any attachments.