On Thu, Sep 01, 2005 at 10:25:24PM +0200, Marcus Holland-Moritz wrote:
> I think this is a bug in Perl itself that was introduced with
> 5.8.0 and is still present. It can be cut down to this code:
>
> #!perl -wl
> use Tie::Hash;
> tie %h, "Tie::StdHash";
> $a = 3.55;
> $_ = $a + 0;
> $h{a} = $a;
> print $h{a}, ", ", @h{qw(a)};
>
> __END__
>
> [EMAIL PROTECTED] ~ $ perl5.6.2 test.pl
> 3.55, 3.55
>
> [EMAIL PROTECTED] ~ $ perl5.8.0 test.pl
> 3.55, 3
>
> [EMAIL PROTECTED] ~ $ bleadperl test.pl
> 3.55, 3
It's down to the different ways Perl_sv_2pv_flags handles magic and
non-magic values. In the former case, it does mg_get(), which happens to set
the SV with NOK,pIOK,pNOK flags and IV = 3, NV = 3.55.
Then, the C<if (SvGMAGICAL(sv))> branch prefers I over N:
if (SvIOKp(sv)) {
....
goto tokensave;
}
if (SvNOKp(sv)) {
so stringifies to "3".
The non-magical branch only does the I thing if there isn't an N thing:
if (SvIOK(sv) || ((SvIOKp(sv) && !SvNOKp(sv)))) {
so it stringifies to "3.55".
I wouldn't really like to venture what the correct fix is, epecially as
I'm still consfused about the meanings of the public verses private N/I/P
flags.
--
Wesley Crusher gets beaten up by his classmates for being a smarmy git,
and consequently has a go at making some friends of his own age for a
change.
-- Things That Never Happen in "Star Trek" #18
