[Rd] plot functions, formula interfaces and NAs

[Thomas Lumley]

On Mon, 3 May 2004, Prof Brian Ripley wrote:

> I believe no function should be using getOption("na.action") without a
> means to override it, and thus the formula methods of
>
> boxplot, mosaicplot and  pairs
>
> should get an na.action argument.  Further, since in all cases the
> non-formula methods do handle missing values, I think the default should
> be na.pass.  That is a change in behaviour, but the existing behaviour is
> undocumented.
>

As I know Brian realises, but other people may not, it is not sufficient
just to add na.action=na.pass as a default argument in a function that
uses the usual match.call/eval.parent method to handle formulas.  The
default will be overridden by the default in model.frame.


	-thomas