[Rd] callNextMethod()
John Marsland
john.marsland at wmgfunds.com
Wed Apr 20 19:33:03 CEST 2005
I have built a sequence of eight S4 classes, each of which inherits
from the previous one but adds extra slots.
I have a corresponding generic function for which I have described
methods for each of these classes in a signature with one other
variable. There are also some ad hoc variable outside the signature
which have different default values for each class.
Each method calls callNextMethod() to populate the slots which it has
in common with the previous class and then some additional code to
populate the new slots in the class.
Before writing each new method the selectMethod() function correctly
identifies the method which I would like to call from the
callNextMethod() function. But after 3-4 levels of nesting the method
seem unable to identify the correct next method and returns nothing but
continues without error.
I'm sorry, but I couldn't reproduce the problem with a simple example.
But after countless hours of debug, a thorough reading of the Green
Book and various attempts with the trace() function - this just drops
the trace within callNextMethod(), again without error - , I have
exhausted all my ideas for what is wrong.
All I can think is there might be a problem in callNextMethod(), making
it inconsistent with selectMethod(). It also not clear to me how
default values are passed through to the next method.
Is there a recommended debug process for this sort of problem? Is there
a way call a specific method with a defined signature from within the
new method definition?
Regards,
John Marsland
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