Re^4: exiting a subroutine neatly (Throwable)

But then, you are using exceptions for flow control when what you really need is some kind of unwind-protect. For instance Guard.

use Guard qw(scope_guard);

sub ssh_execute_and_check {
  my $ssh = shift;
  my ($ret, $err) = $ssh->execute(@_);
  if ( $err or $ret =~ /Unknown command:/m ) {
      MyErr->throw({err => $err, ret => $ret, args => [@_]});
  }
  return $ret;
}

sub foo {

   $ssh->start_session($ssh_host) or MyErr->throw(...);

   scope_guard {
       $ssh->exit_session;
       $ssh->close_session;
   };

   my $ret1 = ssh_execute_and_check($ssh, 'command1', 'expect1');
   my $ret2 = ssh_execute_and_check($ssh, 'command2', 'expect2');

   ...
  
   1;
}
[download]

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Re^5: exiting a subroutine neatly (Throwable) by Anonymous Monk on May 05, 2015 at 11:08 UTC
But then, you are using exceptions for flow control when what you really need is some kind of unwind-protect. For instance Guard. How do you figure? I raise an exception in case of error -- this isn't using exceptions for flow control, exceptions aren't used to return a value from the sub so I included both ret and err in the exception -- this isn't using exceptions for flow control ... I simply didn't scrutinize the if statement beyond counting/naming the vars which I included in the exception	[reply]
Re^6: exiting a subroutine neatly (Throwable) by salva (Canon) on May 05, 2015 at 11:28 UTC
How do you figure? Looking at your code: `sub foo { ... try { fooFoo($ssh); } catch { warn "warn cought one: $_"; }; $ssh->exit_session; $ssh->close_session; }` [download] What I mean is that you should let your exceptions go uncaught for upper levels where they can be handled properly. There is no reason to couple the exception catching with the cleanup code.	[reply] [d/l]
Re^7: exiting a subroutine neatly (Throwable) by Anonymous Monk on May 05, 2015 at 16:43 UTC
What I mean is that you should let your exceptions go uncouth for upper levels where they can be handled properly. There is no reason to couple the exception catching with the cleanup code. Oh that, yes, I assume foo is the topmost level If it isn't, rethrow `my $exception = try { ... } \|\| { $$_; }; $ssh->exit_session; $ssh->close_session; $exception and $exception->throw;` [download] Rethrow versus Guard? Eeeh :)	[reply] [d/l]