From the documentation for setMethod():
Method definitions can have default expressions for arguments, but a
current limitation is that the generic function must have some default
expression for the same argument in order for the method's defaults to
be used. <>
(It would be nice to fix
I am trying to understand the missing vs default value for an argument
to an S4 method. (I'm not sure if this is a bug or my confusion.) In S3
I can specify a default value for an argument and then both check if the
argument was missing in the call, and use it because it takes on the
default value.
