> On Dec 6, 2017, at 07:45, Joshua Ulrich <josh.m.ulr...@gmail.com> wrote:
>
> To avoid excessive dependencies, I would like to only register
> foo.bar() if package A is installed at the time package B is
> installed. If package A is installed after package B, then warn the
> user when package B is loaded and/or attached, so they can re-install
> A and have foo.bar() registered correctly.
One simple solution would be to wrap the instantiation of foo.bar in a require
test:
if (require(A)) {
foo.bar <- function(...) {
print("To be or not to be")
}
} else {
message("To use the foo.bar function, please install package A.")
}
Thanks,
Bill
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