[R-pkg-devel] Creating Accessor Methods

[Kasper Daniel Hansen]

Creating functions that looks like they have the same name, but have
different internals is exactly (one of) the purposes of having methods.

Best,
Kasper

On Thu, Mar 10, 2016 at 4:04 PM, Glenn Schultz <glennmschultz at me.com> wrote:

> Hello Joris,
>
> Thank worked perfectly.  My main concern was that I was creating multiple
> methods which may have the same name but different signature. Just over
> thinking things I guess but I appreciate your time answering my question.
>
> Glenn
>
> > On Mar 10, 2016, at 8:13 AM, Joris Meys <Joris.Meys at Ugent.be> wrote:
> >
> > Hi Glenn,
> >
> > that is actually as easy as defining a generic and defining a method for
> each class to extract the slot. I do this literally in every package I
> write.
> >
> > setGeneric('duration', function(x, ...) standardGeneric('duration')
> >
> > setMethod('duration', signature = 'MBSCashFlow', function(x) { x at Duration
> })
> > setMethod('duration', signature = 'REMICCashFlow', function(x)
> {x at Duration})
> > etc...
> >
> > I suggest you take a close look at Hadley Wickham's books 'Advanced R'
> and 'R packages', both freely available online.
> >
> > This is the relevant section of the first book :
> http://adv-r.had.co.nz/OO-essentials.html <
> http://adv-r.had.co.nz/OO-essentials.html>
> > This is the other book : http://r-pkgs.had.co.nz/ <
> http://r-pkgs.had.co.nz/>
> >
> > Cheers
> > Joris
> >
> > On Thu, Mar 10, 2016 at 3:05 PM, Glenn Schultz <glennmschultz at me.com
> <mailto:glennmschultz at me.com>> wrote:
> > All,
> >
> > I have a package with to S4 classes (MBSCashFlow, REMICCashFlow and
> BondCashFlow) all of which contain the slot Duration.  I would like have an
> accessor Duration that would work on multiple signatures.  Is this
> possible?  I have checked my books, help, BioConductor tutorials and it
> appears that this is not possible.  Has anyone ever run into this situation?
> >
> > Best Glenn
> > ______________________________________________
> > R-package-devel at r-project.org <mailto:R-package-devel at r-project.org>
> mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-package-devel <
> https://stat.ethz.ch/mailman/listinfo/r-package-devel>
> >
> >
> >
> > --
> > Joris Meys
> > Statistical consultant
> >
> > Ghent University
> > Faculty of Bioscience Engineering
> > Department of Mathematical Modelling, Statistics and Bio-Informatics
> >
> > tel : +32 9 264 59 87
> > Joris.Meys at Ugent.be
> > -------------------------------
> > Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php <
> http://helpdesk.ugent.be/e-maildisclaimer.php>
>
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