Re: [PATCH] java.util.StringTokenizer assumes order of parameterevaluation

[Ranjit Mathew <rmathew at hotmail dot com>]

Sorry guys, but I just referred to the JLS (section 15.12.4.2,
"Evaluate Arguments"):

http://java.sun.com/docs/books/jls/second_edition/html/expressions.doc.html#45449

and I quote:

"The argument expressions are evaluated in order, from left to right..."

Therefore, the coder for StringTokenizer *can* assume the
order of evaluation - there must be some other problem that
I need to figure out.

BTW, does GCJ guarantee this order at all times? (I just saw
Andrew Haley's patch for a fix for *static* method invocation,
but the StringTokenizer problem is in a member method.)

Sincerely Yours,
Ranjit.

Ranjit Mathew wrote:
> Hi,
>
>     Lars Andersen recently pointed out a bug to me
> in the class java.util.StringTokenizer in GCJ 3.2 for
> Windows that I ultimately traced to a trivial oversight
> in the class's code - it assumes the order in which
> parameters are evaluated in code like:
>
>     return str.substring(pos, ++pos);
>
> The class works fine at least with GCJ 3.2 on Solaris
> but not on Windows. I *think* this is the problem, but
> I could very well be mistaken - the problem disappears
> if I make this change though.
>
> In any case, here's the patch:
> ------------------------ 8< ------------------------------
> --- StringTokenizer.java.orig   Wed Oct 16 12:14:20 2002
> +++ StringTokenizer.java        Wed Oct 16 12:16:35 2002
> @@ -182,5 +182,9 @@
>        {
>          if (retDelims)
> -          return str.substring(pos, ++pos);
> +         {
> +           String retVal = str.substring(pos, pos+1);
> +           pos++;
> +           return retVal;
> +         }
>          while (++pos < len && delim.indexOf(str.charAt(pos)) >= 0);
>        }
> ------------------------ 8< ------------------------------
>
> There's more code in the class which makes such assumption
> and possibly these are there in other classes as well.
>
> I'm attaching Lars's original mail at the end of this mail
> for your reference.
>
> Sincerely Yours,
> Ranjit.

--
Ranjit Mathew          Email: rmathew AT hotmail DOT com

Bangalore, INDIA.      Web: http://ranjitmathew.tripod.com/