[R-pkg-devel] Force namespace prefix for a loaded package function

http://www.keittlab.org/

On Mon, Jun 27, 2016 at 3:22 AM, Joris Meys <jorismeys at gmail.com> wrote:

If you want to call a non exported function, you need three colons

X:::f ()

And frankly, that is a bad idea.

I think you missed the point (and stated the obvious).

A well-designed namespace feature would give control of imports to the code
user, not the code writer.

Right now, I have to avoid all the function names in base because I will
cause a collision. If I want to have an "options" function in my package, I
have to make it "pkgname_options" rather than pkgname::options, which is
greatly preferable and would allow the user to decide whether they want to
import it and then simply use "options" and "base::options".

I've always considered this all-or-nothing approach to imports a bug in the
implementation of namespaces in R. I was trying to suggest that it be
fixed. (Probably should have sent this to r-devel actually.)

THK

Cheers
Joris
On 26 Jun 2016 19:37, "Tim Keitt" <tkeitt at utexas.edu> wrote:

It would be rather nice if we could define functions in our packages that
must be called with the namespace prefix.

I'd like to do

#' @protected (or some such)
f = function(...) list(...)

in package scope and then

library(x)
f(1)             # fails
x::f(1)         # succeeds

Currently unless I am missing something, a function is either exported to
global scope or not available. This could be done if package loading made
two environments, one in the path and another not in the path, and then
have the namespace prefix search both in succession.

Yes, you could do

#' @export
x_f = function(...) list(...)

library(x)
x_f(1)

but I would prefer reusing the namespace prefix syntax.

This would also avoid name collisions between package, which ideally is
the
purpose of a namespace.

I suppose also you could make two packages and list one in Imports: but I
find that less satisfying because it requires a different namespace
prefix.

Or am I missing something obvious here.

THK

http://www.keittlab.org/

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