Need an example of using emptyValueDelimiterPolicy

[Costello, Roger L.]

Hi Folks,

Suppose the input is an integer that is initiated by a left parenthesis and 
terminated by a right parenthesis, e.g.,

(44)

I thought that I would use emptyValueDelimiterPolicy for that input, using this 
schema:

<xs:sequence dfdl:initiator="(" dfdl:terminator=")" >
    <xs:element         name="num"
                type="xs:integer"
                minOccurs="0"
                dfdl:emptyValueDelimiterPolicy="both" /> 
</xs:sequence>

Question #1: Is that a legitimate scenario for using emptyValueDelimiterPolicy?

Question #2: Does Daffodil support emptyValueDelimiterPolicy? This message 
seems to suggest that Daffodil does not support it:

[warning] Schema Definition Warning: DFDL property was ignored: 
emptyValueDelimiterPolicy="both"

/Roger