Duncan Murdoch wrote:
> I'm writing wrappers for some functions that change some of the default
> arguments. I'd rather not list all of the arguments for the low level
> functions because there are about a dozen wrapper functions, and about
> 20 arguments to lowlevel. Instead I'm trying something like this:
>
> lowlevel <- function(longname = 1) {
> cat("longname = ", longname, "\n")
> }
>
> wrapper <- function(...) {
> newargs <- list(longname = 2)
> newargs[names(list(...))] <- list(...)
> do.call("lowlevel", newargs)
> }
>
> This almost works:
>
> > wrapper()
> longname = 2
> > wrapper(longname = 3)
> longname = 3
>
> But it fails if I try to use partial argument matching:
>
> > wrapper(long=4)
> Error in lowlevel(longname = 2, long = 4) :
> unused argument(s) (long ...)
>
> because long isn't matched to longname. Is there a reasonable way to do
> this (e.g. using pmatch or charmatch) other than listing all the low
> level arguments in the argument list to wrapper?
>
> Duncan Murdoch
If all you are doing is changing the default values of some arguments
this should work.
wrapper <- lowlevel
formals(wrapper) <- replace(formals(lowlevel), c("longname"), list(2))
Charles
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