我在使用Perl子例程引用作为左值时遇到了问题。我是在这里做错了什么,还是不可能这样做?我在Windows上使用ActiveState Perl 5.20。谢谢
package Warning {
use strict;
use warnings;
use Carp 'carp';
sub new {
my $class = shift;
return bless [@_], $class;
}
sub initbyname {
my $self = shift;
$self = $self->new unless ref $self;
carp "'Warning' object already initialized" if @$self;
while (@_) {
my $method = shift;
my $value = shift;
my $sub = $self->can($method);
$sub ? ( $sub->() = $value ) :
( carp "method '$method' not found" );
}
return $self;
}
sub biff :lvalue { $_[0]->[ 0] }
sub boff :lvalue { $_[0]->[ 1] }
}
package ThisWorks {
use strict;
use warnings;
use Carp 'carp';
sub new {
my $class = shift;
return bless [@_], $class;
}
sub initbyname {
my $self = shift;
$self = $self->new unless ref $self;
carp "'ThisWorks' object already initialized" if @$self;
while (@_) {
my $method = shift;
my $value = shift;
$self->can($method) ? ( $self->$method = $value ) :
( carp "method '$method' not found" );
}
return $self;
}
sub riff :lvalue { $_[0]->[ 0] }
sub roff :lvalue { $_[0]->[ 1] }
}
package main;
use v5.20;
use strict;
use warnings;
my $warning = Warning->initbyname( boff => 12 );
my $thisworks = ThisWorks->initbyname( roff => 13 );
say "warning->boff = ", $warning->boff // "uninitialized!";
say "thisworks->roff = ", $thisworks->roff;
打印:
Useless assignment to a temporary at a.pl line 17.
warning->boff = uninitialized!
thisworks->roff = 13
(好吧,我设法删除了空行,但现在它被格式化为代码。我想我需要一个“markdown”中的类。)
