api: Working with Packages
In renozao/repotools: Tools for R Package Repositories

available.pkgs returns a matrix of the packages available in given repositories.

download.pkgs downloads packages.

exists.pkgs tells if packages are available from repositories.

Library tries loading packages and install them if needed.

available.pkgs(...)

download.pkgs(pkgs, destdir, available = NULL, ...)

exists.pkgs(pkgs, repos = getOption("repos"), ..., value = FALSE,
  fixed = TRUE)

old.pkgs(lib.loc = NULL, repos = getOption("repos"), available = NULL,
  ..., type = getOption("pkgType"), verbose = TRUE)

## S3 method for class 'pkgs'
update(lib.loc = NULL, repos = getOption("repos"),
  instlib = NULL, ask = TRUE, available = NULL, oldPkgs = NULL, ...,
  type = getOption("pkgType"), dry.run = NULL, verbose = TRUE)

Library(package, lib.loc = NULL, ...)

`...`	additional arguments to be passed to `download.file`.
`pkgs`	character vector of the names of packages whose latest available versions should be downloaded from the repositories.
`destdir`	directory where downloaded packages are to be stored.
`available`	an object as returned by `available.packages` listing packages available at the repositories, or `NULL` which makes an internal call to `available.packages`.
`repos`	character vector, the base URL(s) of the repositories to use, i.e., the URL of the CRAN master such as `"https://cran.r-project.org"` or its Statlib mirror, `"http://lib.stat.cmu.edu/R/CRAN"`.
`value`	logical, used only when `fixed=FALSE`, that indicates if the name of the matched packages should be returned (instead of a `TRUE/FALSE` logical value.
`fixed`	logical that indicates if the elements of `x` should match exactly (`TRUE`) or interpreted and matched as regular expressions.
`lib.loc`	character vector describing the location of R library trees to search through (and update packages therein), or `NULL` for all known trees (see `.libPaths`).
`type`	character string, indicate which type of packages: see `install.packages` and ‘Details’.
`verbose`	verbosity level (logical or numeric)
`instlib`	character string giving the library directory where to install the packages.
`ask`	logical that specifies if the user should be asked before installling the available updates, or if these should be directly installed.
`oldPkgs`	if specified as non-NULL, `update.packages()` only considers these packages for updating. This may be a character vector of package names or a matrix as returned by `old.packages`.
`dry.run`	logical that indicates if one should only return the computed set of packages and dependencies to install. If `NULL`, then it is internally set to `TRUE` only when there is a mismatch between the requested and the OS binary package types (e.g., if `type = 'win.both'` on a Unix/Mac host).
`package`	the name of a package, given as a name or literal character string, or a character string, depending on whether `character.only` is `FALSE` (default) or `TRUE`).