"Simon Fear" <[EMAIL PROTECTED]> writes: > It's one of the many situations in which I would very much like to > get a warning or error message, pointing out to me that I had > absolutely no idea what I was doing. > > Surely that's what warnings are for? For those of us who wonder why > our code doesn't do what we think it should, until a long time after > the deadline?
It's rarely advisable to nanny users too much though (as someone said: protecting users from doing dumb things may also prevent them from doing smart things). In the case of warnings, it is not a good thing if they can trigger due to circumstances beyond the user's control. Consider the following: f <- function(mydata,...){ attach(mydata) ...do something... detach(mydata) } mydata <- whatever... attach(mydata) f(mydata[1:100,]) What should happen? A warning that "mydata already exists on the search path" or so, perhaps? OK, so we just don't do that then. But suppose that f is sitting in a package and the user has no knowledge of its internals. You have then the side effect of the package that it implicitly forbids the user to attach a dataframe called "mydata", even if everything functions perfectly normally when one is present. Imagine having to explain that in the package documentation! -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help