How to distinguish between blank and 0 values in BML for float configuration attributes

Summary:

We are facing the following challenge with BML:

Given a configuration float attribute "attr", displayed as an input box.

The user has the option to leave the attribute empty.

Now let there be a recommendation, which uses "attr" as action input in an advanced BML function.

The value passed in BML is not null if the attribute is left empty, but 0.

However, we need a way to distinguish between a blank field and a 0, as those have different meanings.

The only way we found is by checking for "attr" not equals "" as a simple condition of the recommendation.

This solution is not really usefull in our case though, as this recommendation uses seven different float attributes which all need such an check and different behaviour depending on wether the field is left empty.