[R] dumpClass, hasSlot in R?

[Spencer Graves]

      Venables and Ripley (2000) R Programming (Springer, sec. 5.1) and 
Chambers (1998) Programming with Data (Springer) describe functions such 
as dumpClass and hasSlot that I can not find in R 1.9.1 for Windows nor 
in the "R site search".  What do people use for similar functionality?  
Also, what resources have people found useful for learning about S4 
classes, other than these 2 references? 

      Thanks, Spencer Graves