[Rd] scoping error in xy.coords (PR#932)

[Peter Dalgaard BSA]

Thomas Lumley <tlumley@u.washington.edu> writes:

> evaluates to NULL, and x evaluates to y~x, rather than in the global
> environment where they would both evaluate to vectors.
> 
> In order to handle formulas correctly I think xy.coords needs to use the
> same sort of indirect evaluation as model.frame: eg
>    xy <-substitute(xy.coords(X,Y),list(X=substitute(x),Y=substitute(y)))
>    xy<-eval(xy,parent.frame())
> works as a replacement for the first two lines of lowess().  I hadn't
> realised that xy.coords() was supposed to handle formulas, and since it
> doesn't have a data= argument it can't do it very well.
> 
> This seems a bit drastic, given the number of times xy.coords is used.
> Perhaps there's a simpler solution.

Perhaps use the new formula environments in xy.coords? Seems to work


        if (inherits(x, "formula") && length(x) == 3) {
            ylab <- deparse(x[[2]])
            xlab <- deparse(x[[3]])
            y <- eval(x[[2]], environment(x), parent.frame())
            x <- eval(x[[3]], environment(x), parent.frame())
	}

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907
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