From andre.zege at gmail.com  Tue Apr  5 18:47:23 2011
From: andre.zege at gmail.com (A Zege)
Date: Tue, 5 Apr 2011 11:47:23 -0500 (CDT)
Subject: [Rd] super basic questions about S4 classes
Message-ID: <1302022043304-3428591.post@n4.nabble.com>

Apologies for asking something that is probably super obvious, i just started
with S4 classes and i guess i am not finding documentation that layout the
grammar rules and give enough examples. Some questions i am having are these

1. I understand that main method of writing a member function is to write a
generic function and setMethod for this particular object. This, however,
presumes that there is "virtuality" for this function, i.e. it could be used
with other inherited classes . Truth is, many, if not most of my functions
don't have virtuality in mind. I want to write them inside classes to
achieve incapsulaton only -- use class member data without passing it as
parameters or making global to a bunch of functions and have some specific
class member functions that don't pollute a global namespace and can be
called only for a particular class. This is what i know how to do with
enclosures in R. Is there some obvious way of setting this environment local
to a class without writing generic functions that i am missing?

2. Is it possible to overload functions in other ways than having default
parameter values and prototypes?
For example, can i have  two constructors with completely different sets of
parameters?

3. Is there some good way to debug S4 classes? I am very fond of mtrace()
from debug package, but the simple set of commands i normally use doesn't
take me into class methods. 


Would appreciate any pointers on these..


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[Rd] super basic questions about S4 classes
A Zege