transltr (version 0.1.0)

language_set: Get or Set Language

Description

Get or set the current, and source languages.

They are registered as environment variables named TRANSLTR_LANGUAGE, and TRANSLTR_SOURCE_LANGUAGE.

Usage

language_set(lang = "en")
language_get()
language_source_set(lang = "en")
language_source_get()

Value

language_set(), and language_source_set() return NULL, invisibly. They are used for their side-effect of setting environment variables TRANSLTR_LANGUAGE and TRANSLTR_SOURCE_LANGUAGE, respectively.

language_get() returns a character string. It is the current value of environment variable TRANSLTR_LANGUAGE. It is empty if the latter is unset.

language_source_get() returns a character string. It is the current value of environment variable TRANSLTR_SOURCE_LANGUAGE. It returns "en" if the latter is unset.

Arguments

lang

A non-empty and non-NA character string. The underlying language.

A language is usually a code (of two or three letters) for a native language name. While users retain full control over codes, it is best to use language codes stemming from well-known schemes such as IETF BCP 47, or ISO 639-1 to maximize portability and cross-compatibility.

Locales versus languages

A locale is a set of multiple low-level settings that relate to the user's language and region. The language itself is just one parameter among many others.

Modifying a locale on-the-fly can be considered risky in some situations. It may not be the optimal solution for merely changing textual representations of a program or an application at runtime, as it may introduce unintended changes and induce subtle bugs that are harder to fix.

Moreover, it makes sense for some applications and/or programs such as Shiny applications to decouple the front-end's current language (what users see) from the back-end's locale (what developers see). A UI may be displayed in a certain language while keeping logs and R internal messages, warnings, and errors as is.

Consequently, the language setting of transltr is purposely kept separate from the underlying locale and removes the complexity of having to support many of them. Users can always change both the locale and the language parameter of the package. See Examples.

Details

The language and the source language can always be temporarily changed. See argument lang of method Translator$translate() for more information.

The underlying locale is left as is. To change an R session's locale, use Sys.setlocale() or Sys.setLanguage() instead. See below for more information.

Examples

# Change the language parameters (globally).
language_source_set("en")
language_set("fr")

language_source_get()  ## Outputs "en"
language_get()         ## Outputs "fr"

# Change both the language parameter and the locale.
# Note that while users control how languages are named
# for language_set(), they do not for Sys.setLanguage().
language_set("fr")
Sys.setLanguage("fr-CA")

# Reset settings.
language_source_set(NULL)
language_set(NULL)

# Source language has a default value.
language_source_get()  ## Outputs "en"