Check availability of eventvalue possible?

[Micha_he]

What's the recommended way, to check if the eventvalue contains a value ?

Code: Select all

on eventname do
  if %eventvalue1%=0
    (do something)
  endif
endon

Check for zero seems not work! Can I check for undefined?

[TD-er]

I think the event value will be 0 when not set.
But I do see the use case where it may be practical to have a "Not Set" value.

[Micha_he]

No, it's not 0! The result between:

Event,Eventname

and

Event,Eventname=0 is different. The if-condition isn't true. Also the check '<1' is not true, if no eentvalue is given.

[TD-er]

Ah that's interesting.
Have to look into the code to see why.
Maybe it is also trying to match the "=" sign when searching for the on...do block.

But if you refer to the %eventvalue%, then that one should be 0 when not set.... I think

[ThomasB]

If you are trying to trap an event without a value, then I propose this rule:

Code: Select all

on eventname do
  if %eventvalue%<=0 or %eventvalue%>0
    // (value provided, do something with the value)
  else 
    // (value NOT provided, do some default action)
  endif
endon

I tested this on mega-20200222 and it worked for me.

- Thomas

[Micha_he]

Nice workaround. Works with %eventvalue1% also. Thanks.

[ThomasB]

Nice workaround. Works with %eventvalue1% also. Thanks.

You're welcome. Glad to hear it is working for you.

FWIW, %eventvalue1% is an alias for %eventvalue%. Both are interchangeable.

But if you refer to the %eventvalue%, then that one should be 0 when not set.... I think

There are probably some applications that can benefit from knowing when the eventvalue has not been assigned. So defaulting it to zero would prevent that. I'd recommend leaving things as-is. Or if preferred, allow the rules to test for %NULL% (unassigned) values.

- Thomas