[R] Proper way to document print( ) functions

ripley@stats.ox.ac.uk ripley at stats.ox.ac.uk
Thu Mar 6 22:41:29 CET 2003

The simplest way is to define the method correctly, as print.myclass(x,
myarg, ...).  That message is about the code, not the documentation, but
you will get a different one if the code and documentation disagree.

All print methods must include `...', and there is a section in `Writing R
Extensions' on why.  In brief, I should be able to define class
`richerclass' inheriting from `myclass' and have a print method for
`richerclass' with different arguments that calls NextMethod("print").

BTW this applies equally to S-PLUS.

On Thu, 6 Mar 2003, Frank E Harrell Jr wrote:

> Frequently we have a print method, say print.myclass, that has a variety of arguments.  If in the .Rd file I say
> \usage{
> \method{print}{myclass}(x, myarg)
> }
> I get a warning when running R CMD chk:
> * checking generic/method consistency ... WARNING
> print:
>   function(x, ...)
> print.myclass:
>   function(x, myarg)
> What is the proper way to handle this?
> Thanks

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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