R/LoadandCite.R

In christophergandrud/repmis: Miscellaneous Tools for Reproducible Research

#' Install, load, and cite R packages
#'
#' \code{LoadandCite} can install and load R packages as well as automatically
#' generate a BibTeX file citing the packages.
#' @param pkgs a character vector of R package names. If \code{pkgs = NULL} then
#' \code{LoadandCite} only cites the non-base packages in the current session.
#' It does not load or install any packages.
#' @param versions character vector of package version numbers to install. Only
#' works if \code{install = TRUE}. The order must match the order of package
#' names in \code{pkgs}.
#' @param Rversion a character string specifying a particular R version. If the
#' version of R currently running differs from \code{Rversion}
#' \code{LoadandCite} a warning will be given. This argument is for replication
#' purposes.
#' @param bibtex logical. If \code{TRUE} than a BibTeX formatted citation file
#' is created. If \code{FALSE} than the citations are returned as plain text.
#' @param style character string indicating stylistic elements to add to the
#' citations. Currently supports \code{'plain'}, i.e. no special formatting and
#' \code{'JSS'} to match the BibTeX style for the
#' \emph{Journal of Statistical Software}
#' (see \url{http://www.jstatsoft.org/style}).
#' @param tweak logical. Whether to fix some known problems in the citations,
#' especially non-standard format of authors.
#' @param install a logical option for whether or not to install the packages.
#' The default is \code{install = FALSE}.
#' @param file the name of the BibTeX file you want to create. If
#' \code{file = NULL} then the packages are loaded, but no BibTeX file is
#' created.
#' @param repos character vector specifying which repository to download
#' packages from. Only relevant if \code{install = TRUE} and versions are not
#' specified. If \code{repos = NULL}, automatically reads user defined
#' repository (via \code{options}), but defaults to
#' \code{repos = "http://cran.us.r-project.org"} if \code{repos} is not set.
#' @param lib character vector giving the library directories where to install
#' the packages. Recycled as needed. If \code{NULL}, defaults to the first
#' element of \code{.libPaths()}. Only relevant if \code{install = TRUE}.
#' @details The command can install R packages, load them, and create a BibTeX
#' file that can be used to cite the packages in a LaTeX or similar document. It
#' can be useful to place this command in a \code{knitr} code chunk at the
#' beginning of a reproducible research document. Note: the command will
#' overwrite existing files with the same name as \code{file}, so it is
#' generally a good idea to create a new BibTeX file with \code{LoadandCite}.
#' @examples
#' # Create vector of package names
#' ## In this example you need to have the packages installed aready.
#' PackNames <- "repmis"
#' # Load the packages and create a BibTeX file
#' LoadandCite(pkgs = PackNames, file = 'PackageCites.bib', style = 'JSS')
#' \dontrun{
#' # Install, load, and cite specific package versions
#' # dontrun due to CRAN restrictions
#' Names <- c("e1071", "gtools")
#' Vers <- c("1.6", "2.6.1")
#' LoadandCite(pkgs = Names, versions = Vers, install = TRUE,
#'              file = "PackageCites.bib")
#' }
#' @source
#' Gandrud, Christopher (2013). Automating R Package Citations in Reproducible
#' Research Documents. SSRN.
#' This function is partially based on: \url{https://gist.github.com/3710171}.
#' It also builds on code from knitr's \code{write_bib}. See: Y. Xie. knitr: A
#' general-purpose package for dynamic report generation in R, 2013. URL
#' \url{http://CRAN.R-project.org/package=knitr}. R package version 1.5. Note
#' that it does not formally depend on knitr so that knitr can be included in
#' \code{LoadandCite} so that it is possible to install old versions of that
#' package.
#' @seealso \code{write_bib}, \code{\link{install.packages}}, and
#' \code{\link{library}}
#' @importFrom utils install.packages installed.packages
#'
#' @export

LoadandCite <- function(pkgs = NULL, versions = NULL, Rversion = NULL,
                        bibtex = TRUE, style = 'plain', tweak = TRUE,
                        install = FALSE, file = NULL, repos = NULL, lib = NULL)
{
    Loaded <- search()
    Loaded <- subset(Loaded, grepl(pattern = 'package:', Loaded))
    Loadedpkgs <- gsub(pattern = 'package:', replacement = '', Loaded)
    if (is.null(pkgs)){
    if (is.null(file)){
        stop("A file must be specified for saving the citations to if pkgs = NULL.")
    }
        write_bibExtra(Loadedpkgs, file = file, bibtex = bibtex, style = style,
                        tweak = tweak)
    }
    else if (!is.null(pkgs)){
    if (!is.null(Rversion)){
        RV <- RVNumber()
        if (!isTRUE(Rversion == RV)){
            warning(paste0("The version of R currently running (", RV,
            ") is different from the version specified (", Rversion,
            "). To improve replication, please install the archived version from your local CRAN mirror."))
        }
    }
    if (is.null(lib)){
        lp <- .libPaths()
        lib <- lp[1]
    }
    if (!isTRUE(install) & !is.null(versions)){
        warning("If you want to install specific package versions, also set install = TRUE.")
    }
      if (is.null(repos)){
        r <- ifelse(!is.null(getOption('repos')), getOption('repos'),
                    "http://cran.us.r-project.org")
    } else if (!is.null(repos)){
        r <- repos
    }

    # Find packages/package versions that are not already installed
    InstalledpkgsFull <- installed.packages()
    IPSub <- InstalledpkgsFull[InstalledpkgsFull[, "Package"] %in% pkgs, ]
    if (!is.null(versions)){
        IPSub <- IPSub[IPSub["Version"] %in% versions]
        if (length(IPSub) == 0){
            install = FALSE
            message("All installed packages are the of the specified version. No packages will be installed.")
        }
    }
    ############ Need subed package and version list in the same order #######
    if(install){
        if (is.null(versions)){
            install.packages(pkgs = IPSub, repos = r, lib = lib)
            } else if (!is.null(versions)){
                InstallOldPackages(pkgs = IPSub, versions = versions, lib = lib)
            }
    }

    # Load unloaded packages
    NotLoadedpkgs <- pkgs[!(pkgs %in% Loadedpkgs)]
    lapply(NotLoadedpkgs, library, character.only = TRUE)

    # Write BibTeX file
    ########## Add in packages that are loaded but not in pkgs ##########
    if (!is.null(file)){
        write_bibExtra(pkgs, file = file, bibtex = bibtex, style = style,
                        tweak = tweak)
    }
  }
}