Rails I18n fallback experiment

i18n_fallbacks.rb

require "i18n/backend/fallbacks"

I18n::Backend::Simple.send :include, I18n::Backend::Fallbacks

I18n.backend.store_translations :en, test: {
  no_translations: {
    specific: "en specific",
    generic: "en generic",
  },
  only_generic_translations: {
    specific: "en specific",
    generic: "en generic",
  },
  complete_translations: {
    specific: "en specific",
    generic: "en generic",
  },
}

I18n.backend.store_translations :"en-AU", test: {
  no_translations: {
  },
  only_generic_translations: {
    generic: "au generic",
  },
  complete_translations: {
    specific: "au specific",
    generic: "au generic",
  },
}

def text key
  I18n.t :"test.#{key}.specific", default: [:"test.#{key}.generic", "string fallback"]
end

def check key
  printf "%5s | %s\n", I18n.locale, text(key)
end

for test in %w[no_translations only_generic_translations complete_translations]
  puts
  puts "Test case #{test}"
  puts "=" * 20
  I18n.locale = :"en"
  check test
  I18n.locale = :"en-AU"
  check test
end

Test case no_translations
====================
   en | en specific
en-AU | en specific

Test case only_generic_translations
====================
   en | en specific
en-AU | au generic

Test case complete_translations
====================
   en | en specific
en-AU | au specific