with_something: Execute code in temporarily altered environment.

Description

in_dir: working directory
with_collate: collation order
with_envvar: environmental variables
with_libpaths: library paths, replacing current libpaths
with_lib: library paths, prepending to current libpaths
with_locale: any locale setting
with_options: options
with_path: PATH environment variable
with_par: graphics parameters

Usage

with_envvar(new, code, action = "replace")
with_locale(new, code)
with_collate(new, code)
in_dir(new, code)
with_libpaths(new, code)
with_lib(new, code)
with_options(new, code)
with_par(new, code)
with_path(new, code, add = TRUE)
with_makevars(new, code, path = file.path("~", ".R", "Makevars"))

Arguments

new

values for setting

code

code to execute in that environment

action

(for with_envvar only): should new values "replace", "suffix", "prefix" existing environmental variables with the same name.

add

Combine with existing values? Currently for with_path only. If FALSE all existing paths are overwritten, which don't you usually want.

path

location of existing makevars to modify.

Details

if NA is used as a value with with_envvar those environment variables will be unset. If there are any duplicated variable names only the last one is used.

If no existing makevars file exists or the fields in new do not exist in the existing Makevars file then the fields are added to the new file. Existing fields which are not included in new are appended unchanged. Fields which exist in Makevars and in new are modified to use the value in new.