Prov-WD: valueType in ValueDescription and ParameterDescription unclear

[Ole Streicher]

Good morning,

the attrbutes valueType in ValueDescription and ParameterDescription
have the description (2.6.2 "ValueEntity and ValueDescription classes",
table 18, pg.28):

"VODML value type, see Lemson and Laurino et al. (2016)"

I doubt that this is usable, since it basically allows *all* VO-DML
value types:

 * PrimitiveType
 * Enumeration
 * DataType
 * ObjectType

Having some complex ObjectType stored in a Value is however not
interoperable, since the serialization as string is not at all defined,
which makes it impossible for a client to interpret the value. It is
also unclear what to fill into that field. The hwole VO-DML id? What
about locally defined ObjectTypes?

Also I doubt that we shuld allow f.e. Quantities here (since they
duplicate the unit).

IMO the only cases we have so far are the simple types: strings and
numbers (integer and floating point). We should restrict here to those,
or significantly improve the documentation.

Best

Ole