Readonlybynames the declaration references rather than states as literals, e.g. an R6 inherit = Generator
Readonlycontainsthe direct superclasses, in the order the declaration lists them (S7/R6 have at most one)
Readonlymembersthe slots/properties/fields the declaration states, in order
Optional Readonlynamethe declared class name, absent when the naming argument does not resolve to a literal
Optional Readonlyprototypethe members the prototype gives a default for; the defaults themselves are values, which no declaration model carries
Optional Readonlyrelationthe declaration only relates two existing classes (setIs) or attaches a validator (setValidity), it declares no class of its own
ReadonlysystemOptional Readonlyunionthe members of a setClassUnion, which are subclasses of it rather than superclasses
Optional Readonlyvirtualthe class cannot be instantiated: representation("VIRTUAL"), contains = "VIRTUAL", S7 abstract = TRUE, or a class union
What one class-declaring call states. Everything but system is best-effort: an argument that does not resolve statically is left out rather than guessed.