.NET, Ruby and PHP libraries for schema.org: classes vs enumerations

Hi all,

We're currently working on creating PHP and Ruby libraries that port the
great work that @RehanSaeed <https://github.com/RehanSaeed/> has done over
at https://github.com/RehanSaeed/Schema.NET/, as part of the OpenActive.io
<https://www.openactive.io/> project.

We've come across an interesting problem in how we map schema.org
enumerations to equivalent language constructs in .NET, Ruby and PHP.

There are quite a few classes
<https://github.com/RehanSaeed/Schema.NET/issues/92#issuecomment-546991622>
that
appear to be *both* a class and an enumeration:

   - https://schema.org/PaymentCard inherits from *both* Enumeration and
   Service:
      - Thing > Intangible > Enumeration > PaymentMethod > PaymentCard
      - Thing > Intangible > Service > FinancialProduct > PaymentCard
   - https://schema.org/DrugClass inherits from *just* Enumeration, but has
   a property ("drug"), so appears to be treated like a class
   - http://schema.org/BedType and other subclasses of QualitativeValue
   <https://schema.org/QualitativeValue> and MedicalEnumeration
   <https://schema.org/MedicalEnumeration> display properties in the
   schema.org GUI, so appear to be available as a class?

Discussing <https://github.com/RehanSaeed/Schema.NET/issues/92> with
@RehanSaeed, we're unsure what logic should be applied for determining
whether an rdfs:Class from the JSON-LD
<https://schema.org/version/4.0/schema.jsonld> representation should appear
in the library as an enum vs as a class with properties.

Our current assumption is that anything that subclasses
https://schema.org/Enumeration should be strictly an enum (which is how
Schema.NET works at present).

<https://github.com/RehanSaeed/Schema.NET/issues/92>See further details
here: https://github.com/RehanSaeed/Schema.NET/issues/92

Any hints greatly appreciated?

Many thanks,

Nick