These generic functions return version information for classes
derived from Versioned-class, or
VersionsNull-class for unversioned objects. The
version information is an object of Versions-class.
By default, classVersion has the following behaviors:
classVersion(Versioned-instance)- Returns a
Versions-class object obtained from the object.
classVersion{"class"}Consults the definition of class and return the current version information, if available.
classVersion(ANY)Return a VersionsNull-class object to indicate no version information available.
By default, the classVersion<- method has the following behavior:
classVersion(Versioned-instance)["id"] <- value- Assign (update or add)
value to Versions-instance. value is coerced to a valid version description. see Versions-class for additional access methods.