[R] warning on generic function when building R package

[Jim Lemon]

I think what you may have done is simply changed x.init= to x=x.init.
x.init may or may not be there when the function is called, and that is
what the warning is saying. While you have satisfied the restriction that
the first argument must be "x", but then set the default value to something
that R is unable to resolve to a value. What you may want to do is
something like this:

plot.func<-function(x,y,...) {
 if(missing(x)) stop("Must have an x value")
 if(missing(y)) stop("Must have a y value")
 ...
}

Jim


On Tue, Oct 20, 2015 at 7:32 AM, carol white via R-help <
r-help at r-project.org> wrote:

> In effect, this works
> but whether I use x or x.init, y or y.init in plot.func, I get
>
> no visible binding for global variable ‘x.init’no visible binding for
> global variable ‘y.init’
> Regards,
>
>      On Monday, October 19, 2015 9:59 PM, Duncan Murdoch <
> murdoch.duncan at gmail.com> wrote:
>
>
>  On 19/10/2015 3:50 PM, carol white wrote:
> > Thanks Murdoch.
> >
> > defining
> > plot.func<- function(x=x.init, y=y.init, arg3, arg4, "title", col, arg5)
> >
> > and if plot doesn't take the exact parameters of plot.func but modified
> > of these parameters
> > plot(x=x.pt,y=y.pt,xlim = c(0, 10), ylim = c(0,1), xlab= "xlab",
> > ylab="ylab", main = "title", col = col,type = "l")
> >
> > then, how to define and invoke to be consisent?
>
> I don't really understand your question, but this is all about the
> function header for plot.func, not the call you make to plot().  You
> need to name the first argument as "x", you need to include "..." as an
> open argument, and you need a legal header.  So this would be okay:
>
>
> plot.func<- function(x=x.init, y=y.init, arg3, arg4,
>                     main = "title", # can't skip the arg name
>                     col, arg5,
>                     ...)  {          # can't skip the dots
>
> Duncan Murdoch
>
> >
> > Regards,
> >
> > On Monday, October 19, 2015 7:45 PM, Duncan Murdoch
> > <murdoch.duncan at gmail.com> wrote:
> >
> >
> > On 19/10/2015 1:29 PM, carol white via R-help wrote:
> >
> >> Hi,I have invoked plot in a function (plot.func) as follows but when I
> > check the built package, I get a warning:
> >> plot(x.pt,y.pt,xlim = c(0, 10), ylim = c(0,1), xlab= "xlab",
> > ylab="ylab", main = "title", col = col,type = "l")
> >> R CMD check my.package
> >> checking S3 generic/method consistency ... WARNING
> >> plot:
> >>  function(x, ...)
> >> plot.func:
> >>  function(x.pt, y.pt, arg3, arg4, "title", col, arg5)
> >>
> >> See section ‘Generic functions and methods’ in the ‘Writing R
> >> Extensions’ manual.
> >> Which plot argument is illegitimate or missing and how to eliminate
> > the warning?
> >
> >
> > The first argument to plot.func needs to be called "x" if you want to
> > use it as a method.  Method signatures need to be consistent with the
> > generic signature.
> >
> > Duncan Murdoch
> >
> >
> >
> >
>
>
>
>
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>
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