[Rd] new function to tools/utils package: dependencies based on DESCRIPTION file

Jan Górecki J.Gorecki at wit.edu.pl
Tue Jun 14 18:29:06 CEST 2016

Hi Thierry,

I'm perfectly aware of it. Any idea when devtools would be shipped as
a base R package, or at least recommended package? To actually answer
the problem described in my email.
I have range of useful functions available tools/utils packages which
are shipped together with R. They doesn't require any OS dependencies
or R dependencies, unlike devtools which requires both. Installing
unnecessary OS dependencies and R dependencies just for such a simple
wrapper doesn't seem to be an elegant way to address it, therefore my
proposal to include that simple function in tools, or utils package.

Jan Gorecki

On 14 June 2016 at 16:17, Thierry Onkelinx <thierry.onkelinx at inbo.be> wrote:
> Dear Jan,
> Similar functionality is available in devtools::dev_package_deps()
> Best regards,
> ir. Thierry Onkelinx
> Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
> Forest
> team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
> Kliniekstraat 25
> 1070 Anderlecht
> Belgium
> To call in the statistician after the experiment is done may be no more than
> asking him to perform a post-mortem examination: he may be able to say what
> the experiment died of. ~ Sir Ronald Aylmer Fisher
> The plural of anecdote is not data. ~ Roger Brinner
> The combination of some data and an aching desire for an answer does not
> ensure that a reasonable answer can be extracted from a given body of data.
> ~ John Tukey
> 2016-06-14 16:54 GMT+02:00 Jan Górecki <J.Gorecki at wit.edu.pl>:
>> Hi all,
>> Packages tools and utils have a lot of useful stuff for R developers.
>> I find one task still not as straightforward as it could. Simply to
>> extract dependencies of a package from DESCRIPTION file (before it is
>> even installed to library). This would be valuable in automation of CI
>> setup in a more meta-data driven way.
>> The simple function below, I know it is short and simple, but having
>> it to be defined in each CI workflow is a pain, it could be already
>> available in tools or utils namespace.
>> package.dependencies.dcf <- function(file = "DESCRIPTION", which =
>> c("Depends","Imports","LinkingTo")) {
>>     stopifnot(file.exists(file), is.character(which))
>>     which_all <- c("Depends", "Imports", "LinkingTo", "Suggests",
>> "Enhances")
>>     if (identical(which, "all"))
>>         which <- which_all
>>     else if (identical(which, "most"))
>>         which <- c("Depends", "Imports", "LinkingTo", "Suggests")
>>     stopifnot(which %in% which_all)
>>     dcf <- read.dcf(file, which)
>>     # parse fields
>>     raw.deps <- unlist(strsplit(dcf[!is.na(dcf)], ",", fixed = TRUE))
>>     # strip stated dependency version
>>     deps <- trimws(sapply(strsplit(trimws(raw.deps), "(", fixed =
>> TRUE), `[[`, 1L))
>>     # exclude base R pkgs
>>     base.pkgs <- c("R", rownames(installed.packages(priority = "base")))
>>     setdiff(deps, base.pkgs)
>> }
>> This allows to easily install all package dependencies just based on
>> DESCRIPTION file, so simplify that in custom CI workflows to:
>> if (length(pkgs<-package.dependencies.dcf(which="all")))
>> install.packages(pkgs)
>> And would not require to install custom packages or shell scripts.
>> Regards,
>> Jan Gorecki
>> ______________________________________________
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