Constraints on property with measure

[CBenghi]

For discussion and documentation:

When specifying a property with a measure (other than string and number) values will have to be transformed from the unit defined in the model to the relevant SI unit for testing.

So I propose that any relevant restriction adheres to the following implementation agreements:

• [ ] we should expect base type to be double.
• [ ] pattern and structure restrictions should be considered invalid (as they do not make sense on the converted value)

[berlotti]

now using IFC defined types, still with fixed values. We might need to make a list of what xs base types map to what ifc defined types (with fixed units).

Patterns could still be valid.

[CBenghi]

Hi @berlotti, regarding patterns, do you expect it to be useful that we convert a length expressed in feet in the model to meters, then apply a regular expression patter to evaluate if the value passes? I can't see how it would be used, but you do, please document a case in the repo. Thanks, Claudio

[CBenghi]

I've added the capability to constrain valid xs:facets depending on the base type of restrictions. For the time being this is constrained to the types defined in the XML documentation, but we might want to implement stricter implementation agreements.