*print '[', $self->name, " is being destroyed...]\n"; * 猜你的本意是：
* print '[', ref $self, " is being destroyed...]\n"; 改成如上这样就OK了，这是因为 $self 此时是 Barn, 没有 name 这个方法，直接就异常退出了。* 2010/4/8 andy white <[email protected]> > { package Animal; > sub name { > my $either = shift; > ref $either > ? $either->{Name} > : "an unnamed $either"; > } > sub named { > my $class = shift; > my $name = shift; > my $self = { Name => $name, Color => $class->default_color }; > bless $self, $class; > } > > sub default_color { 'brown' } > sub DESTROY { > my $self = shift; > print '[', $self->name, " has died.]\n"; > } > } > { package Cow; > @ISA = qw( Animal ); > } > { package Barn; > sub new { bless [ ], shift } > sub add { push @{+shift}, shift } > sub contents { @{+shift} } > sub DESTROY { > my $self = shift; > print '[', $self->name, " is being destroyed...]\n"; > for($self->contents) { > print ' ', $_->name, " goes homeless.\n"; > } > } > } > > my $barn = Barn->new; > $barn->add(Cow->named('Bessie')); > $barn->add(Cow->named('Gwen')); > print "Burn the barn:\n"; > $barn = undef; > print "End of program.\n"; > > 现在的程序的运行结果的是： > Burn the barn: > [Gwen has died.] > [Bessie has died.] > End of program. > > 当$barn = undef时，调用的是Animal的DESTROY方法。 > > 我想要的结果是还要调用Barn的DESTROY方法(并且打印contents的内容)，即 > Burn the barn: > Barn=ARRAY(0x541c) is being destroyed... > Bessie goes homeless. > Gwen goes homeless. > [Gwen has died.] > [Bessie has died.] > End of program. > > 问题出在那里阿？那位帮忙看看吧！ > > -- > 您收到此邮件是因为您订阅了 Google 网上论坛的“PerlChina Mongers 讨论组”论坛。 > 要向此网上论坛发帖，请发送电子邮件至 [email protected]。 > 要取消订阅此网上论坛，请发送电子邮件至 > [email protected]<perlchina%[email protected]> > 。 > 若有更多问题，请通过 http://groups.google.com/group/perlchina?hl=zh-CN 访问此网上论坛。 > -- 您收到此邮件是因为您订阅了 Google 网上论坛的“PerlChina Mongers 讨论组”论坛。 要向此网上论坛发帖，请发送电子邮件至 [email protected]。 要取消订阅此网上论坛，请发送电子邮件至 [email protected]。 若有更多问题，请通过 http://groups.google.com/group/perlchina?hl=zh-CN 访问此网上论坛。
