wb_require: Use Packages from Way-Back-Then
In petermeissner/wayback: Rock Solid Package Installation for Legacy R Versions

Description Usage Arguments Details Examples

This function will make sure a specified package is available within the current R session. If the package is not available it will attempt to install it and load it thereafter. If its already installed it will only load the package.

wb_require(
  pkg,
  library_path = getOption("wb_require_lib_path", NULL),
  date = getOption("wb_require_date", NULL),
  date_shift = getOption("wb_require_shift_date", NULL),
  package_path = getOption("wb_require_package_path", NULL),
  dependencies = getOption("wb_require_dependencies", c("Depends", "Imports",
    "LinkingTo")),
  url_fun = getOption("wb_require_url", wb_repo_url)
)

`pkg`	`character` - package name specified as cha
`library_path`	`character` - lib_path to use first
`date`	`character` - date specified in ISO format, defaults to date specified in `sessionInfo()$R.version$version.string`
`date_shift`	`integer` - number of days to add to date
`package_path`	`character` - path to look for binary packages to install
`dependencies`	`character vector` - specifies which types of dependencies should be installed also
`url_fun`	function transforming a date into a repository url

Other than the normal install.packages function this function will not use the newest package available but one that was available at a specific point in time on CRAN. For CRAN snapshots the Microsoft R Open snapshots and the checkpoint package are used.

The default date is the date of the release of the R version currently in use plus an additional 60 days.

The lib_path argument can be used to make use a project specific R package library path.

Also, its possible to specify a path were binary packages can be found and installed from.

## Not run: 

# set options
options(wb_require_lib_path = "./r_lib_path")

# make sure package is available
wb_require("data.table")

# use packages released up to 365 days younger than the current R-versions
# release date
wb_require("data.table", date_shift = 365)

# use a specific lib path for loading and installing
wb_require("data.table", lib_path = "./r_lib_path")


## End(Not run)