Question

我有一个模块，它给出了错误“无法找到对象方法”isSubset“via package”a“（也许你忘了加载”a“？）在/path/to/set.pm第121行

SET.PM：

package set; #we will create set objects, instead of treating arrays as sets

sub new{
    my $packagename = shift;
    my @elements = @_;
    bless { 'elements' => \@elements } => $packagename;
}

sub contains{
    my $set = shift;
    my ($element) = @_;
    foreach ($set->elements){ if( $_ eq $element ){ return 1 } }
    return 0
}
sub isElement{
    my ($element,$set) = @_;
    return $set->contains($element)
}

sub isSubset{
    my $setA = shift;
    my $setB = shift;
    foreach ($setA->elements){ unless( isElement($_,$setB) ){ return 0 } }
    return 1
}
*subset = *isContainedIn = *isContained = \&isSubset;
sub isSuperset{
    my $setA = shift;
    my $setB = shift;
    return $setB->isSubset($setA) # this is line 121
}
*superset = *isContaining = *contains = \&isSuperset; # when i get rid of THIS line, it works fine.

当我注释掉最后一行时，它运行正常。你能告诉我导致失败的原因吗？我错误地使用了水滴？

致电计划：

my $a = set->new('a'..'g');
my $b = set->new('b'..'f');
print $a->isSubset($b);

Answer 1

开启warnings。 Perl会告诉你：

Subroutine set::contains redefined at ./1.pl line 44.

您使用contains来测试元素和集合。

glob（star）运算符，方法消失，Perl

1 个答案: