From 3b61d057c1b5f844913a2e1bef1ba8f293b97846 Mon Sep 17 00:00:00 2001 From: Hadley Wickham Date: Thu, 4 Nov 2021 07:59:24 -0500 Subject: [PATCH] Implement with_language() and local_language() (#180) Uses LC_MESSAGES to reset cache on windows, and warns in two scenarios where setting the LANGUAGE will fail to have any effect. --- DESCRIPTION | 3 ++- NAMESPACE | 2 ++ NEWS.md | 3 +++ R/language.R | 48 ++++++++++++++++++++++++++++++++++ man/with_language.Rd | 30 +++++++++++++++++++++ tests/testthat/test-language.R | 14 ++++++++++ 6 files changed, 99 insertions(+), 1 deletion(-) create mode 100644 R/language.R create mode 100644 man/with_language.Rd create mode 100644 tests/testthat/test-language.R diff --git a/DESCRIPTION b/DESCRIPTION index 74bc3222..e9833251 100644 --- a/DESCRIPTION +++ b/DESCRIPTION @@ -57,7 +57,7 @@ VignetteBuilder: knitr Encoding: UTF-8 Roxygen: list(markdown = TRUE) -RoxygenNote: 7.1.1 +RoxygenNote: 7.1.2 Collate: 'local_.R' 'with_.R' @@ -71,6 +71,7 @@ Collate: 'dir.R' 'env.R' 'file.R' + 'language.R' 'libpaths.R' 'locale.R' 'makevars.R' diff --git a/NAMESPACE b/NAMESPACE index f0e7b40a..b4a4dd77 100644 --- a/NAMESPACE +++ b/NAMESPACE @@ -16,6 +16,7 @@ export(local_environment) export(local_envvar) export(local_file) export(local_jpeg) +export(local_language) export(local_libpaths) export(local_locale) export(local_makevars) @@ -53,6 +54,7 @@ export(with_environment) export(with_envvar) export(with_file) export(with_jpeg) +export(with_language) export(with_libpaths) export(with_locale) export(with_makevars) diff --git a/NEWS.md b/NEWS.md index 38ecc5f6..034688ab 100644 --- a/NEWS.md +++ b/NEWS.md @@ -1,5 +1,8 @@ # withr (development version) +* New `with_language()` and `local_language()` to temporarily control the + language used for translations (#180). + * `with_seed()` now caches the check for R version, so is now faster (#170) * `with_makevars()` and `local_makevars()` now eagerly evaluate the `path` argument (#169) diff --git a/R/language.R b/R/language.R new file mode 100644 index 00000000..6b8bbd8c --- /dev/null +++ b/R/language.R @@ -0,0 +1,48 @@ +#' Language +#' +#' Temporarily change the language used for translations. +#' +#' @param lang A BCP47 language code like "en" (English), "fr" (French), +#' "fr_CA" (French Canadian). Formally, this is a lower case two letter +#' [ISO 639 country code](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes), +#' optionally followed by a "_" and an upper case two letter +#' [ISO 3166 region code](https://en.wikipedia.org/wiki/ISO_3166-2). +#' @inheritParams with_collate +#' @export +#' @examples +#' with_language("en", try(mean[[1]])) +#' with_language("fr", try(mean[[1]])) +#' with_language("es", try(mean[[1]])) +with_language <- function(lang, code) { + local_language(lang) + code +} + +#' @export +#' @rdname with_language +local_language <- function(lang, .local_envir = parent.frame()) { + if (!has_nls()) { + warning("Changing language has no effect when R installed without NLS") + } + + # > Note: The variable LANGUAGE is ignored if the locale is set to ‘C’. + # > In other words, you have to first enable localization, by setting LANG + # > (or LC_ALL) to a value other than ‘C’, before you can use a language + # > priority list through the LANGUAGE variable. + # --- https://www.gnu.org/software/gettext/manual/html_node/The-LANGUAGE-variable.html + if (identical(Sys.getenv("LANG"), "C")) { + warning("Changing language has no effect when envvar LANG='C'") + } + + local_envvar(LANGUAGE = lang, .local_envir = .local_envir) + if (Sys.info()[["sysname"]] != "Windows") { + # Reset cache to avoid gettext() retrieving cached value from a previous + # language. I think this works because Sys.setlocale() calls setlocale() + # which https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=931456 claims + # resets the cache. So if there's some OS/setup that this technique fails + # on, we might try bindtextdomain() instead or as well. + local_locale(c(LC_MESSAGES = ""), .local_envir = .local_envir) + } +} + +has_nls <- function() capabilities("NLS")[[1]] diff --git a/man/with_language.Rd b/man/with_language.Rd new file mode 100644 index 00000000..ec2d80f1 --- /dev/null +++ b/man/with_language.Rd @@ -0,0 +1,30 @@ +% Generated by roxygen2: do not edit by hand +% Please edit documentation in R/language.R +\name{with_language} +\alias{with_language} +\alias{local_language} +\title{Language} +\usage{ +with_language(lang, code) + +local_language(lang, .local_envir = parent.frame()) +} +\arguments{ +\item{lang}{A BCP47 language code like "en" (English), "fr" (French), +"fr_CA" (French Canadian). Formally, this is a lower case two letter +\href{https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes}{ISO 639 country code}, +optionally followed by a "_" and an upper case two letter +\href{https://en.wikipedia.org/wiki/ISO_3166-2}{ISO 3166 region code}.} + +\item{code}{\code{[any]}\cr Code to execute in the temporary environment} + +\item{.local_envir}{\verb{[environment]}\cr The environment to use for scoping.} +} +\description{ +Temporarily change the language used for translations. +} +\examples{ +with_language("en", try(mean[[1]])) +with_language("fr", try(mean[[1]])) +with_language("es", try(mean[[1]])) +} diff --git a/tests/testthat/test-language.R b/tests/testthat/test-language.R new file mode 100644 index 00000000..7631455e --- /dev/null +++ b/tests/testthat/test-language.R @@ -0,0 +1,14 @@ +test_that("can temporary change language", { + skip_if_not(has_nls()) + + expect_error(with_language("en", mean[[1]]), "not subsettable") + expect_error(with_language("fr", mean[[1]]), "non indi\u00e7able") + expect_error(with_language("es", mean[[1]]), "no es subconjunto") +}) + +test_that("warns if LANG=C", { + skip_if_not(has_nls()) + + local_envvar(LANG = "C") + expect_warning(with_language("en", "x"), "has no effect") +})