(This is crosspost from [1]http://stackoverflow.com/questions/18670895/how-to-write-a-wrapper-functi on-which-can-honour-default-values-when-the-target, posted week ago, where although the question did receive some attention, nobody was able to help me.) I'd like to write a more-or-less generic caller to `targetf` that retains its default parameters. Suppose we have a provided by some 3rd party library `targetf`: targetf<-function(x=1,...){ print(paste("x =",x)) } How to write `wrapperf`, that will respect `targetf`s default arguments, so calling `wrapperf()` would not yield the error massage `Error in paste("x =", x) : argument "x" is missing, with no default`? The obvious candidate wrapperf1<-function(x,y) { targetf(x=x) } doesn't seem to respect targetf's default value for parameter `x`. OTH the wrapperf2<-function(...) { targetf(...) } behaves correctly, but it doesn't work for me, because I only care to pass the `x` argument, (and possibly reserve the `...` to other functions in `wrapperf` body). Maybe to solve the issue I'd have to play with ellipsis filtering, which is a *terra incognita* for me at the moment... * * * One idea on how to solve the problem: maybe I'd need to create a specially crafted `...` object from scratch in `wrapperf` to do pseudo code like this: wrapperfX<-function(x,y,...) { ...<-if(missing(x){ list() }else{ list(x=x) } targetf(...) } But I have no idea how to even start doing assignments into ellipsis... is it possible at all? kind regards, Adam Ryczkowski
[2]www.statystyka.net [3]+48505919892 [4]Skype:sisteczko References 1. http://stackoverflow.com/questions/18670895/how-to-write-a-wrapper-function-which-can-honour-default-values-when-the-target 2. http://www.google.com/ 3. callto:+48505919892 4. skype:sisteczko ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
