Re: [mh] Returning 0 as a value and not false?

I thought about that, but I was hoping that power_changed would work similar to state_changed. I’d also have to put that defined check in reset_power, and I thought there was something about defined that was either being depreciated or was changing in a newer version of perl.

From what I’ve read, I think I’m going to check if power is 0 and then return 0E0 . This apparently is a ‘0 but true’ perl workaround. It should be seen as true, and should be treated as a 0 for numeric operations. The only downside to this is that it will display funny in print_log in this example:

if (my $power = power_changed $item) {
  print_log("Power has now changed to $power");
}

However the workaround would be

if (power_changed $item) {
  my $power = power $item;
  print_log("Power has now changed to $power");
}

I’ll try this and see how it works.

> On Feb 14, 2023, at 6:28 PM, Timothy Spaulding <[email protected]> wrote:
> 
> Ok, here is another idea; (my Perl is getting rusty and so I don't know which will work)
> 
> if (power_changed $item >= 0) {
> ...
> }
> 
> or
> 
> if (power_changed $item ge 0) {
> ...
> }
> 
> 
> -----Original Message-----
> From: H Plato <[email protected]> 
> Sent: Tuesday, February 14, 2023 4:33 PM
> To: Timothy Spaulding <[email protected]>
> Cc: misterhouse list <[email protected]>
> Subject: Re: [mh] Returning 0 as a value and not false?
> 
> Thanks Tim. That part actually works, it’s the usercode:
> 
> if (power_changed $item) {
> 	#do something
> }
> 
> this works great except when the power is a 0. So the reset works, it’s just the power_changed sub, because I want the actual power value in power_changed (similar to state_changed), if the valid changed value is 0, the if statement in usercode will fail.
> 
> Does that explain it better?
> 
>> On Feb 14, 2023, at 1:34 PM, Timothy Spaulding <[email protected]> wrote:
>> 
>> Would this work?
>> 
>> 
>> sub reset_power_state {
>>   my ($self) = @_;
>>       if (defined($self->{power_state_changed})) {
>>           if ($self->{power_state_changed_loop}) { #wait for a loop to reset power_state_changed
>> 
>> 
>> -----Original Message-----
>> From: H Plato <[email protected]> 
>> Sent: Tuesday, February 14, 2023 2:51 PM
>> To: misterhouse list <[email protected]>
>> Subject: [mh] Returning 0 as a value and not false?
>> 
>> I’ve been testing out the power monitoring on the tasmota module with good success. It’s nice to see an RRD as well to profile a few devices.
>> 
>> I’ve run into a snag though, that I think is easy but the solution is eluding me. To allow for monitoring power changes, I have a power_changed method. each time new power data comes in, I compare the new value to the old one, and if they are different, $self->{power_state_changed} is set to that value. This works great _except_ for 0 values. 0 can be a valid state (and in fact I need to see it to determine if something is turned off), however 0 is being interpreted as false, so the power_changed method is never set.
>> 
>> Does anyone have any suggestions on how to pass along a 0 value so the method will work? I thought maybe returning 0.0 as a 0 might work, but that seems like a kludge.
>> 
>> --
>> sub reset_power_state {
>>   my ($self) = @_;
>>       if ($self->{power_state_changed}) {
>>           if ($self->{power_state_changed_loop}) { #wait for a loop to reset power_state_changed
>>               undef $self->{power_state_changed};
>>               $self->{power_state_changed_loop} = 0;
>>           } else {
>>               $self->{power_state_changed_loop} = 1;
>>           }
>>       }
>> }
>> 
>> 
>> sub update_power {
>>   my ($self,$power, $current) = @_;
>>   $self->{monitor}->{prevpower} = $self->{monitor}->{power};
>>   $self->{monitor}->{power} = $power;
>>   $self->{monitor}->{maxpower} = $power if ($self->{monitor}->{power} > $self->{monitor}->{maxpower});
>>   $self->{power_state_changed} = $power unless ($self->{monitor}->{prevpower} == $self->{monitor}->{power});
>>   $self->{monitor}->{prevcurrent} = $self->{monitor}->{current};
>>   $self->{monitor}->{current} = $current;    
>>   $self->{monitor}->{maxcurrent} = $current if ($self->{monitor}->{current} > $self->{monitor}->{maxcurrent}); }
>> 
>> 
>> sub power_changed {
>>   my ($self) = @_;
>>   return $self->{power_state_changed};
>> 
>> 
>> 
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>> 
> 



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