as this probably doesn't have one solution I am interested in your approach, if you have any.

The problem is that often you want to create instances (or just return constants) in some particular domain, e.g.

Color red.

Color blue.

Unfortunately this doesn't scale, because putting unary methods on the class-side is a good way to break your image.

doesn't follow method naming conventions

Color Red.

ParticipantType Organization (uncapitalized returns ClassOrganization)

VisibilityKind Package (package returns package)

need for an extra singleton and more typing

Color default red.

ParticipantType default organization.

VisibilityKind default package.

maybe #enum could work better?

Color enum red.

VisibilityKind enum package.

looks like C/Java��� ugly af

also same issue as 1)

may not be enough, can be confusing when implementing a domain with given specifications

Color redColor.

ParticipantType organizationType.

VisibilityKind packageKind

All the above work (obviously) but all are broken to some extent��� so it's picking the best of the worst. -_-

Any ideas appreciated,

Peter