Implement po_create()/po_update() for creating/updating translations

DESCRIPTION

@@ -14,3 +14,4 @@ URL: https://github.com/MichaelChirico/potools
 BugReports: https://github.com/MichaelChirico/potools/issues
 Encoding: UTF-8
 VignetteBuilder: knitr
+RoxygenNote: 7.1.2

NAMESPACE

@@ -11,6 +11,9 @@ export(translate_package)
 export(get_message_data)
 export(write_po_file, po_metadata)
 
+export(po_create)
+export(po_update)
+
 export(check_cracked_messages, check_untranslated_cat, check_untranslated_src)
 
 export(check_potools_sys_reqs)

R/msgmerge.R

@@ -1,6 +1,15 @@
 # split off from tools::update_pkg_po() to only run the msgmerge & checkPoFile steps
-run_msgmerge = function(po_file, pot_file) {
-  if (system(sprintf("msgmerge --update %s %s", po_file, shQuote(pot_file))) != 0L) {
+
+# https://www.gnu.org/software/gettext/manual/html_node/msgmerge-Invocation.html
+run_msgmerge = function(po_file, pot_file, previous = FALSE) {
+  cmd <- paste("msgmerge",
+    "--update",
+    if (previous) "--previous", # show previous match for fuzzy matches
+    shQuote(path.expand(po_file)),
+    shQuote(path.expand(pot_file))
+  )
+
+  if (system(cmd) != 0L) {
     # nocov these warnings? i don't know how to trigger them as of this writing.
     warningf("Running msgmerge on '%s' failed.", po_file)
   }
@@ -70,3 +79,66 @@ update_en_quot_mo_files <- function(dir, verbose) {
   }
   return(invisible())
 }
+
+
+
+#' Create or update a `.po` file containing translations
+#'
+#' @description
+#' * `po_create()` creates a new `po/{languages}.po` containing the messages to be
+#'   translated.
+#' * `po_update()` updates an existing `.po` file after the messages in a
+#'   package have changed. The translations for existing messages are preserved;
+#'   new messages are added; and translations for deleted message are marked
+#'   as deprecated and moved to the bottom of the file.
+#'
+#' @param languages Language identifiers. These are typically two letters (e.g.
+#'   "en" = English, "fr" = French, "es" = Spanish, "zh" = Chinese), but
+#'   can include an additional suffix for languages that have regional
+#'   variations (e.g. "fr_CN" = French Canadian, "zh_CN" = simplified
+#'   characters as used in mainland China, "zh_TW" = traditional characters
+#'   as used in Taiwan.)
+#' @param dir Path to package root.
+#' @param verbose If `TRUE`, explain what's happening.
+po_create <- function(languages, dir = ".", verbose = TRUE) {
+  package <- get_desc_data(dir)[["Package"]]
+  po_path <- po_path(dir, languages)
+  if (file.exists(po_path)) {
+    po_update(languages, dir = dir, verbose = verbose)
+    return(invisible())
+  }
+
+  if (verbose) messagef("Adding new %s translation", languages)
+  run_msginit(pot_path(dir, package), po_path, languages)
+}
+
+#' @rdname po_create
+po_update <- function(languages, dir = ".", verbose = TRUE) {
+  package <- get_desc_data(dir)[["Package"]]
+
+  if (verbose) messagef("Updating existing %s translation", languages)
+  run_msgmerge(po_path(dir, languages), pot_path(dir, package), previous = TRUE)
+}
+
+po_path <- function(dir, lang) {
+  file.path(dir, "po", paste0("R-", lang, ".po"))
+}
+pot_path <- function(dir, package) {
+  file.path(dir, "po", paste0("R-", package, ".pot"))
+}
+
+# https://www.gnu.org/software/gettext/manual/html_node/msginit-Invocation.html
+run_msginit <- function(pot_path, po_path, locale, width = 80) {
+  cmd <- paste("msginit",
+    "-i", shQuote(path.expand(pot_path)),
+    "-o", shQuote(path.expand(po_path)),
+    "-l", shQuote(locale),
+    "-w", width,
+    "--no-translator" # don't consult user-email etc
+  )
+  if (system(cmd) != 0L) {
+    stopf("running msginit on '%s' failed", pot_path)
+  }
+  return(invisible())
+}
+

potools.Rproj

@@ -18,3 +18,4 @@ StripTrailingWhitespace: Yes
 BuildType: Package
 PackageUseDevtools: Yes
 PackageInstallArgs: --no-multiarch --with-keep.source
+PackageRoxygenize: rd