It could be changed to missing(y) || is.null(y) and the docs amended. That way existing code will continue to work and code that otherwise gives an error currently, but should have worked, will now work too.
On 12/31/05, Duncan Murdoch <[EMAIL PROTECTED]> wrote: > On 12/30/2005 10:10 PM, Gabor Grothendieck wrote: > > In ?xy.coords it says: > > > > If 'y' is missing and 'x' is a > > > > formula: of the form 'yvar ~ xvar'. 'xvar' and 'yvar' are used as > > x and y variables. > > > > list: containing components 'x' and 'y', these are used to define > > plotting coordinates. > > > > time series: the x values are taken to be 'time(x)' and the y > > values to be the time series. > > > > matrix with two columns: the first is assumed to contain the x > > values and the second the y values. > > > > however, in fact, if y is missing an error is given. e.g. > > > > x <- 1:3 > > y <- 4:6 > > xy.coords(y ~ x) # error > > xy.coords(cbind(x, y)) # error > > xy.coords(ts(y)) # error > > > > Looking at the code, is.null(y) in the first line of the > > body should be missing(y) . > > It would be better to change the docs to say "if 'y' is NULL ...". The > code has been the way it is for years and years, and is widely used. > > Changing the test to missing(y) would mean all existing uses that put a > NULL there would need to be changed. > > Adding a default value of NULL to y would have less impact, but I'd > still be worried about it having long-range bad effects. > > Duncan Murdoch > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
