with_package: Execute code with a modified search path

In withr: Run Code 'With' Temporarily Modified Global State

Execute code with a modified search path

Description

with_package() attaches a package to the search path, executes the code, then removes the package from the search path. The package namespace is not unloaded however. with_namespace() does the same thing, but attaches the package namespace to the search path, so all objects (even unexported ones) are also available on the search path.

Usage

with_package(
  package,
  code,
  pos = 2,
  lib.loc = NULL,
  character.only = TRUE,
  logical.return = FALSE,
  warn.conflicts = FALSE,
  quietly = TRUE,
  verbose = getOption("verbose")
)

local_package(
  package,
  pos = 2,
  lib.loc = NULL,
  character.only = TRUE,
  logical.return = FALSE,
  warn.conflicts = FALSE,
  quietly = TRUE,
  verbose = getOption("verbose"),
  .local_envir = parent.frame()
)

with_namespace(package, code, warn.conflicts = FALSE)

local_namespace(package, .local_envir = parent.frame(), warn.conflicts = FALSE)

with_environment(
  env,
  code,
  pos = 2L,
  name = format(env),
  warn.conflicts = FALSE
)

local_environment(
  env,
  pos = 2L,
  name = format(env),
  warn.conflicts = FALSE,
  .local_envir = parent.frame()
)

Arguments

package	[character(1)] package name to load.
code	[any] Code to execute in the temporary environment
pos	the position on the search list at which to attach the loaded namespace. Can also be the name of a position on the current search list as given by search().
lib.loc	a character vector describing the location of R library trees to search through, or NULL. The default value of NULL corresponds to all libraries currently known to .libPaths(). Non-existent library trees are silently ignored.
character.only	a logical indicating whether package or help can be assumed to be character strings.
logical.return	logical. If it is TRUE, FALSE or TRUE is returned to indicate success.
warn.conflicts	logical. If TRUE, warnings are printed about conflicts from attaching the new package. A conflict is a function masking a function, or a non-function masking a non-function. The default is TRUE unless specified as FALSE in the conflicts.policy option.
quietly	a logical. If TRUE, no message confirming package attaching is printed, and most often, no errors/warnings are printed if package attaching fails.
verbose	a logical. If TRUE, additional diagnostics are printed.
.local_envir	⁠[environment]⁠ The environment to use for scoping.
env	[environment()] Environment to attach.
name	name to use for the attached database. Names starting with package: are reserved for library.

Value

[any]
The results of the evaluation of the code argument.

See Also

withr for examples

Examples

## Not run: 
with_package("ggplot2", {
  ggplot(mtcars) + geom_point(aes(wt, hp))
})

## End(Not run)

withr documentation built on Nov. 2, 2023, 5:24 p.m.