bug-fixed version of Hadley Wickham's install_version() method from the devtools package

install_version.R

library(devtools)

install_version <- function (package, version = NULL, repos = getOption("repos"), 
    type = getOption("pkgType"), ...) 
{
    contriburl <- contrib.url(repos, type)
    available <- available.packages(contriburl)

## converting the version to numeric breaks packages that use dashes in their version numbers
#    if (!is.null(version)) {
#        version <- numeric_version(version)
#    }
    if (package %in% row.names(available)) {
        current.version <- available[package, "Version"]
        if (is.null(version) || version == current.version) {
            return(install.packages(package, repos = repos, contriburl = contriburl, 
                type = type, ...))
        }
    }
    con <- gzcon(url(sprintf("%s/src/contrib/Archive.rds", repos), 
        "rb"))
    on.exit(close(con))
    archive <- readRDS(con)
    info <- archive[[package]]
    if (is.null(info)) {
        stop(sprintf("couldn't find package '%s'", package))
    }
    if (is.null(version)) {
        package.path <- info[length(info)]
    }
    else {
        package.path <- paste(package, "/", package, "_", version, 
            ".tar.gz", sep = "")
        if (!(package.path %in% info)) {
            stop(sprintf("version '%s' is invalid for package '%s'", 
                package, version))
        }
    }
    url <- paste(repos, "/src/contrib/Archive/", package.path, 
        sep = "")
    install_url(url, ...)
}