[英]How can I use a code ref as a callback in Perl?
I have the following code in my class : 我班上有以下代码:
sub new {
my $class = shift;
my %args = @_;
my $self = {};
bless( $self, $class );
if ( exists $args{callback} ) {
$self->{callback} = $args{callback};
}
if ( exists $args{dir} ) {
$self->{dir} = $args{dir};
}
return $self;
}
sub test {
my $self = shift;
my $arg = shift;
&$self->{callback}($arg);
}
and a script containing the following code : 和包含以下代码的脚本:
use strict;
use warnings;
use MyPackage;
my $callback = sub {
my $arg = shift;
print $arg;
};
my $obj = MyPackage->new(callback => $callback);
but I receive the following error: 但是我收到以下错误:
Not a CODE reference ...
What am I missing? 我错过了什么? Printing
ref($self->{callback})
shows CODE
. 打印
ref($self->{callback})
显示CODE
。 It works if I use $self->{callback}->($arg)
, but I would like to use another way of invoking the code ref. 它可以工作,如果我使用
$self->{callback}->($arg)
,但我想使用另一种方式来调用代码ref。
The ampersand is binding just to $self
and not the whole thing. &符号仅限于
$self
而不是整个事物。 You can do curlies around the part that returns the reference: 你可以在返回引用的部分周围做curlies:
&{$self->{callback}}($arg);
But the 但是
$self->{callback}->($arg);
is generally considered cleaner, why don't you want to use it? 通常被认为是清洁的,为什么你不想使用它?
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