Adds command to translate a pattern of keys

- Related to #574

lib/i18n/tasks/command/commands/translate.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module I18n::Tasks
+  module Command
+    module Commands
+      module Translate
+        include Command::Collection
+        include I18n::Tasks::KeyPatternMatching
+
+        cmd :translate,
+            pos: '[pattern]',
+            desc: t('i18n_tasks.cmd.desc.translate'),
+            args: [:locale, :locale_to_translate_from, arg(:data_format).from(1), :translation_backend]
+
+        def translate(opts = {})
+          forest = i18n.tree(opts[:from])
+          forest.set_root_key!(opts[:locale])
+
+          if opts[:pattern]
+            pattern_re = i18n.compile_key_pattern(opts[:pattern])
+            forest.select_keys! { |full_key, _node| full_key =~ pattern_re }
+          end
+
+          backend = opts[:backend]&.to_sym || i18n.translation_config[:backend] || :google
+
+          puts forest
+
+          print_forest i18n.translate_forest(forest, from: opts[:from], backend: backend), opts
+        end
+      end
+    end
+  end
+end

lib/i18n/tasks/commands.rb

@@ -8,6 +8,7 @@
 require 'i18n/tasks/command/commands/interpolations'
 require 'i18n/tasks/command/commands/eq_base'
 require 'i18n/tasks/command/commands/data'
+require 'i18n/tasks/command/commands/translate'
 require 'i18n/tasks/command/commands/tree'
 require 'i18n/tasks/command/commands/meta'
 require 'i18n/tasks/command/commander'
@@ -21,6 +22,7 @@ class Commands < Command::Commander
     include Command::Commands::Interpolations
     include Command::Commands::EqBase
     include Command::Commands::Data
+    include Command::Commands::Translate
     include Command::Commands::Tree
     include Command::Commands::Meta
 

spec/i18n_tasks_spec.rb

@@ -387,6 +387,21 @@
       end
     end
 
+    it 'translate pattern' do
+      in_test_app_dir do
+        expect(YAML.load_file('config/locales/en.yml')['en']['used_but_missing']).to be_nil
+        expect(YAML.load_file('config/locales/en.yml')['en']['default_arg']).to be_nil
+      end
+      run_cmd 'translate', '--locale=sv'
+      in_test_app_dir do
+        expect(YAML.load_file('config/locales/en.yml')['en']['used_but_missing']['key']).to eq 'Key'
+        expect(YAML.load_file('config/locales/en.yml')['en']['present_in_es_but_not_en']['a']).to eq 'ES_TEXT'
+        expect(YAML.load_file('config/locales/en.yml')['en']['default_arg']).to eq 'Default Text'
+        expect(YAML.load_file('config/locales/en.yml')['en']['default_plural_arg']).to eq({ 'one' => 'One Text',
+                                                                                            'other' => 'Other Text' })
+      end
+    end
+
     it 'default value: base_value for non-base locale' do
       in_test_app_dir do
         expect(YAML.load_file('config/locales/es.yml')['es']['missing_in_es']).to be_nil