Message: 26
Date: Thu, 21 Apr 2005 09:44:34 +0000
From: "Ali -" <saveez@hotmail.com>
Subject: [Rd] Limitations of generic functions
To: r-devel@stat.math.ethz.ch
Message-ID: <BAY17-F197A50240015116B894904D12C0@phx.gbl>
Content-Type: text/plain; format=flowed
(1) Assume we have some automatic C++ wrapper which , briefly, reads
the C++
files and generates some R files in which the equivalent of the C++
classes
are reconstructed.
(2) As the OO design of R is different to that of C++, some isses
exist when
creating an interface between these two systems. (I said these two
are
'different', I didn't say which one is better or which one is uglier.
So
please save the posts on criticising the designs for somewhere else. I
am
trying to make these two designs talk to each other without judging
them.)
(3) One of these issues is about handling overloaded member functions
in C++
in the form of R classes. Following the discussion followed by my
previous
post, I have decided to wrap the C++ in the form of S4 classes.
(4) Some more assumptions:
(a) A C++ class may have any arbitrary number of overloaded
functions
each of them have some arbitrary number of arguments.
(b) To create the equivalent 'overloaded functions' in R, we need
to
have a generic function with several methods. The arguments
(signature) of
each of these methods are determined by the generic function.
(c) In order to make the automatic wrapper as general as possible,
it
should not know about the arguments of the overloaded functions.
(5) And finally the question: How to define the generic function so
that it
covers any unknown arguments of its methods? Apparently simply using
'...'
does not work.