R/deps.R

In tjtnew/coffee: Stuff that helps me get going

#' List dependencies of a file
#'
#' `deps()` returns a character vector of the direct dependencies for the
#'   specified R or Rmd file.
#'
#' @param filepath File location.
#'
#' @returns Character vector of dependencies.
#'
#' @export
deps <- function(filepath) {
  if(grepl("\\.[Rr]$", filepath, perl = TRUE)) {
    rdeps(filepath)
  } else if (grepl("\\.[Rr]md$", filepath, perl = TRUE)) {
    rmddeps(filepath)
  } else {
    stop(".deps only works for files with extensions .Rmd, .rmd, .R and .r")
  }
}

# find direct dependencies of rscript
rdeps <- function(filepath) {
  dat <- paste(as.character(parse(filepath)), collapse = "\n")
  colon_string <- r"---{([a-zA-Z][\w.]*)(?=:{2,3})}---"
  colon_greg <- gregexpr(colon_string, dat, perl = TRUE)
  colon_deps <- unlist(regmatches(dat, colon_greg), use.names = FALSE)
  lib_string <- r"{(?<=library\(|require\()([a-zA-Z][\w.]*)}"
  lib_greg <- gregexpr(lib_string, dat, perl = TRUE)
  lib_deps <- unlist(regmatches(dat, lib_greg), use.names = FALSE)
  unique(c(lib_deps, colon_deps))
}

# find direct dependencies of Rmd file.
rmddeps <- function(filepath) {
  op <- options(knitr.purl.inline = TRUE)
  on.exit(options(op))
  f <- tempfile()
  on.exit(unlink(f), add = TRUE)
  knitr::purl(input = filepath, output = f, quiet = TRUE, documentation = 0)
  c("rmarkdown", rdeps(f))
}