Give thanks to contributors of a project

give_thanks.R

#' Produce a list of all GitHub contributors to a project
#'
#' If you want a way to give thanks to specific people who have contributed to a project
#' since a given release, this will extract the GitHub user names from a given package's 
#' NEWS file. This assumes that 1) the package has a `NEWS.md` file and 2) the package 
#' uses level 1 headers and semantic versioning for each version in the news file. 
#' 
#' @param package the name of a package
#' @param since a version number (must match a version recorded in the NEWS)
#' @return a character vector with GitHub user names
#' @examples
#' give_thanks("stringr", "1.2.0")
#' give_thanks("pkgdown", "1.0.0")
give_thanks <- function(package = "sandpaper", since = "1.0.0") {
  news <- tinkr::yarn$new(system.file("NEWS.md", package = package))
  predicate <- paste0("[@level=1][md:text[contains(text(),'", since, "')]]")
  xpath <- paste0(".//md:heading", predicate, "/preceding-sibling::*")
  nodes <- xml2::xml_find_all(news$body, xpath, news$ns)
  txt <- xml2::xml_text(xml2::xml_find_all(nodes, ".//md:item//md:text[contains(text(),'@')]", news$ns))
  unique(unlist(stringr::str_extract_all(txt, "([@][[:alnum:]]+)")))
}