Optional Readonlyclassthe arguments naming S4 classes the call uses (Class in new, signature in setMethod)
Optional Readonlygenericthe argument naming the S4 generic the call answers or asks about (f in setMethod)
Optional Readonlygenericappended to the generic named by genericArg (setReplaceMethod("f", ...) answers f<-)
Optional Readonlyinstantiatesthe call creates an instance of the classes its classArgs name, running the methods of the initializer generic and their validity functions
Optional Readonlyregistersthe argument naming an S4 class the call adds to without declaring it (to in setAs): read and registered anew, so a later use depends on this call as well as on the declaration
Optional Readonlyregistersthe call registers its definition as a method of the generic, for the signature the first of its classArgs states (setMethod)
Optional Readonlyreturnsthe call hands back a method of the generic its genericArg names (getMethod, selectMethod)
Which arguments of a call name S4 registrations it depends on rather than declares.