帮助在Perl中传递对class子例程的引用

ste*_*nmm 2 perl perl-module pass-by-reference

我试图将例程传递给Perl模块中的另一个子例程.但是当我传递子引用时,传入的ref不再具有对象数据.也许它不可能这样做.我有一个问题的行是下面的"除非"行:

sub get_flag_end {
   my $self = shift;
   return ( -e "$self->{file}" );
}

sub wait_for_end {
   my $self = shift;
   my $timeout = shift;
   my $poll_interval = shift;

   # Is it even possible to pass the oject subroutine and retain the objects data?
   #unless ( $self->timeout( $timeout, $poll_interval, $self->get_flag_end ) ) { # does not work
   unless ( $self->timeout( $timeout, $poll_interval, \&get_flag_end ) ) {       # call happens but members are empty
      die "!!!ERROR!!! Timed out while waiting for wait_for_end: timeout=$timeout, poll_interval=$poll_interval \n";
   }
}

sub timeout {
   my $self = shift;
   my $timeout = shift;
   my $poll_interval = shift;
   my $test_condition = shift;
   until ($test_condition->() || $timeout <= 0) {
      $timeout -= $poll_interval;
      sleep $poll_interval;
   }
   return $timeout > 0; # condition was met before timeout
}
Run Code Online (Sandbox Code Playgroud)

我知道我可以更改"get_flag_end"例程以将值作为子例程的参数但是如果在"get_flag_end"中完成了一堆内容并且我需要来自该对象的更多成员.我简化了一些代码,使其更容易理解.

dao*_*oad 5

只需关闭并传递给:

sub wait_for_end {
   my $self = shift;
   my $timeout = shift;
   my $poll_interval = shift;

   my $callback = sub { $self->get_flag_end() };

   unless ( $self->timeout( $timeout, $poll_interval, $callback ) ) {
      die "!!!ERROR!!! Timed out while waiting for wait_for_end: timeout=$timeout, poll_interval=$poll_interval \n";
   }
}
Run Code Online (Sandbox Code Playgroud)

更新:

另一个选项是,因为timeout是同一个类的方法,传入方法名称.

sub wait_for_end {
   my $self = shift;
   my $timeout = shift;
   my $poll_interval = shift;

   my $callback = sub { $self->get_flag_end() };

   unless ( $self->timeout( $timeout, $poll_interval, 'get_flag_end' ) ) {
      die "!!!ERROR!!! Timed out while waiting for wait_for_end: timeout=$timeout, poll_interval=$poll_interval \n";
   }
}

sub timeout {
  my $self = shift;
  my $timeout = shift;
  my $poll_interval = shift;
  my $method = shift;

  # Do whatever

  # Now call your method.
  $self->$method();

}
Run Code Online (Sandbox Code Playgroud)

  • @stephenmm,查看perlfaq7"什么是封闭?" http://perldoc.perl.org/perlfaq7.html#What's-a-closure%3f (2认同)