getFromNamespace: Utility functions for Developing Namespaces

Description

Utility functions to access and replace the non-exported functions in a namespace, for use in developing packages with namespaces.

They should not be used in production code (except perhaps assignInMyNamespace, but see the ‘Note’).

Usage

getFromNamespace(x, ns, pos = -1, envir = as.environment(pos))
assignInNamespace(x, value, ns, pos = -1,
                  envir = as.environment(pos))
assignInMyNamespace(x, value)
fixInNamespace(x, ns, pos = -1, envir = as.environment(pos), …)

Arguments

an object name (given as a character string).

value

an R object.

a namespace, or character string giving the namespace.

pos

where to look for the object: see get.

envir

an alternative way to specify an environment to look in.

…

arguments to pass to the editor: see edit.

Value

getFromNamespace returns the object found (or gives an error).

assignInNamespace, assignInMyNamespace and fixInNamespace are invoked for their side effect of changing the object in the namespace.

Warning

assignInNamespace should not be used in final code, and will in future throw an error if called from a package. Already certain uses are disallowed.

Details

assignInMyNamespace is intended to be called from functions within a package, and chooses the namespace as the environment of the function calling it.

The namespace can be specified in several ways. Using, for example, ns = "stats" is the most direct, but a loaded package can be specified via any of the methods used for get: ns can also be the environment printed as <namespace:foo>.

getFromNamespace is similar to (but predates) the ::: operator: it is more flexible in how the namespace is specified.

fixInNamespace invokes edit on the object named x and assigns the revised object in place of the original object. For compatibility with fix, x can be unquoted.

Examples

Run this code

getFromNamespace("findGeneric", "utils")

fixInNamespace("predict.ppr", "stats")
stats:::predict.ppr
getS3method("predict", "ppr")
## alternatively
fixInNamespace("predict.ppr", pos = 3)
fixInNamespace("predict.ppr", pos = "package:stats")

Run the code above in your browser using DataLab

Last chance! 50% off unlimited learning