Expression

Result

Notes

Null

 

Result is empty.

GetAsBoolean ( Null )

0

GetAsBoolean returns 0/1 for expression results. 

not Null

1

The boolean inverse of Null, or 1.

Null = 0

0

False: This is boolean false because FM does not evaluate empty to reserved word False (0).

GetAsBoolean ( Null ) = 0

1

True: The explicit FM boolean interpretation of Null is 0. 

GetAsBoolean ( Null ) = False

1

True: A different adaptation - FM reserved words True and False are evaluated to the boolean 0/1 values, so 0 = 0. 

Null = False

0

False: This is the most interesting case of all. Null is technically empty and False evaluates to boolean 0, so they are not equal. 

Null = ""

1

True: The literal empty string "" evaluates the same in FM as the empty return of Null.,

Code within a custom function can and should use double quotes for empty values "". This decreases custom function dependencies on the "null" function - making them more portable for copy-pasting.