Protecting function names in R

Is it possible in R to protect function names (or variables in general) so that they cannot be masked.

I recently spotted that this can be a problem when creating a data frame with the name "new", which masked a function used by lmer and thus stopped it working. (Recovery is easy once you know what the problem is, here "rm(new)" did it.)开发者_开发技巧

There is an easy workaround for your problem, without worrying about protecting variable names (though playing with lockBinding does look fun). If a function becomes masked, as in your example, it is still possible to call the masked version, with the help of the :: operator.

In general, the syntax is packagename::variablename.

(If the function you want has not been exported from the package, then you need three colons instead, :::. This shouldn't apply in this case however.)

Maybe use environments! This is a great way to separate namespaces. For example:

> a <- new.env()
> assign('printer', function(x) print(x), envir=a)
> get('printer', envir=a)('test!')
[1] "test!"

@hdallazuanna recommends (via Twitter)

new <- 1
lockBinding('new', globalenv())

this makes sense when the variable is user created but does not, of course, prevent overwriting a function from a package.

I had the reverse problem from the OP, and I wanted to prevent my custom functions in .Rprofile from being overridden when I defined a variable with the same name as a function, but I ended up putting my functions to ~/.R.R and I added these lines to .Rprofile:

if("myfuns"%in%search())detach("myfuns")
source("~/.R.R",attach(NULL,name="myfuns"))

From the help page of attach:

One useful ‘trick’ is to use ‘what = NULL’ (or equivalently a
length-zero list) to create a new environment on the search path
into which objects can be assigned by assign or load or
sys.source.

...

## create an environment on the search path and populate it
sys.source("myfuns.R", envir = attach(NULL, name = "myfuns"))