R devel - Jun 2009 - S4 Objects [Sec=Unclassified]

I am new to R programming but have dived into a medium sized modelling software
development project.

Having come from a Java OO background I have a couple of questions about S4
objects.



Is there a way to make S4 slots (and methods) private and hence force the use of
accessor methods?



Is there a straight-forward way to implement pass-by-reference for method
parameters?

I am currently returning and overwritting updated objects which is clunky and
costly and would like a more efficient way of doing this.



Can anyone point me to some useful texts on S4 programming apart from the
following:

Chambers - Software for Data Analysis: Programming with R

Venables - S Programming



Thanks heaps



Troy






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Hi Troy --

Troy Robertson wrote:
> I am new to R programming but have dived into a medium sized modelling
software development project.
> 
> Having come from a Java OO background I have a couple of questions about S4
objects.
> 
> 
> 
> Is there a way to make S4 slots (and methods) private and hence force the
use of accessor methods?

No, except by convention (e.g., 'don't directly access slots
name-mangled in this way'; non-package code must never directly access
slots')
> 
> 
> 
> Is there a straight-forward way to implement pass-by-reference for method
parameters?
> 
> I am currently returning and overwritting updated objects which is clunky
and costly and would like a more efficient way of doing this.
no, copy-on-change is the most common semantic in R; using an
'environment' provides some flexibility, but use with S4 introduces
twists. See this concurrent thread

  https://stat.ethz.ch/pipermail/r-help/2009-June/200038.html

(my 2 cents:) embracing rather than avoiding the paradigm might lead to
different designs, e.g., 'column-oriented' (an S4 instance representing
an entire table) rather than row-oriented (an S4 instance for each row)
data structures.

> 
> 
> Can anyone point me to some useful texts on S4 programming apart from the
following:
> 
> Chambers - Software for Data Analysis: Programming with R
> 
> Venables - S Programming
> 
Gentleman, R Programming for Bioinformatics.

Hope that helps.

Martin
> 
> 
> Thanks heaps
> 
> 
> 
> Troy
> 
> 
> 
> 
> 
> 
> ___________________________________________________________________________
> 
>     Australian Antarctic Division - Commonwealth of Australia
> IMPORTANT: This transmission is intended for the addressee only. If you are
not the
> intended recipient, you are notified that use or dissemination of this
communication is
> strictly prohibited by Commonwealth law. If you have received this
transmission in error,
> please notify the sender immediately by e-mail or by telephoning +61 3 6232
3209 and
> DELETE the message.
>         Visit our web site at http://www.antarctica.gov.au/
> ___________________________________________________________________________
> 
> 	[[alternative HTML version deleted]]
> 
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