Translation infrastructure

addons/block_code/README.md

@@ -66,6 +66,70 @@ Lean into animations! Godot's animations functionality goes beyond just simple a
 
 Please share feedback in the [Godot Forum Block Coding thread](https://forum.godotengine.org/t/block-coding-high-level-block-based-visual-programming/68941).
 
+## Localization
+
+The plugin supports translations through Godot's [gettext][godot-gettext]
+support. We welcome contributions to make the plugin work better in your
+language! However, please note that translations in the Godot editor **will
+only work with Godot 4.4 or newer**.
+
+The gettext PO files are located in the `addons/block_code/locale` directory.
+See the Godot [documentation][godot-gettext] for instructions on working with
+PO files.
+
+[godot-gettext]: https://docs.godotengine.org/en/stable/tutorials/i18n/localization_using_gettext.html
+
+For developers, a few things need to be done to keep the translatable strings
+up to date.
+
+* If files are added or removed, the list of translatable files needs to be
+  updated. This can be done by using the **Add** dialog in the [POT
+  Generation][pot-generation] tab. Or you can use the **Project → Tools →
+  Update BlockCode translated files** menu item in the editor.
+
+* If translatable strings have changed, the POT file needs to be updated. This
+  can be done by using the **Generate POT** dialog in the [POT
+  Generation][pot-generation] tab. Or you can use the **Project → Tools →
+  Regenerate BlockCode POT file** menu item in the editor.
+
+* If the POT file has changed, the PO message files need to be updated. This
+  can be done using the gettext `msgmerge` tool in the
+  `addons/block_code/locale` directory:
+  ```
+  for po in *.po; do
+    msgmerge --update --backup=none "$po" godot_block_coding.pot
+  done
+  ```
+
+[pot-generation]: https://docs.godotengine.org/en/stable/tutorials/i18n/localization_using_gettext.html#automatic-generation-using-the-editor
+
+Strings added in scene files or block definition resources will usually be
+extracted for localization and translated in the editor automatically. Strings
+in scripts need more consideration.
+
+* `Object`s or `Node`s that are not descendents of the Block Coding panel need
+  to have their translation domain set with the `set_block_translation_domain`
+  helper function. This should usually be done in the object's `_init` method
+  to make sure the translation domain is set before that object or any of its
+  descendents (which inherit the translation domain by default) try to use
+  localized strings.
+
+* Usually [`tr`][object-tr] and [`tr_n`][object-tr-n] (or [`atr`][node-atr] and
+  [`atr_n`][node-atr-n] for `Node`s) should be used to mark translatable
+  strings. These will eventually call the domain's
+  [`translate`][domain-translate] or
+  [`translate_plural`][domain-translate-plural] methods, but the `tr` methods
+  respect translation settings on the object instances. The only time the
+  `translate` methods should be called directly is within a static context when
+  an object instance isn't available.
+
+[object-tr]: https://docs.godotengine.org/en/stable/classes/class_object.html#class-object-method-tr
+[object-tr-n]: https://docs.godotengine.org/en/stable/classes/class_object.html#class-object-method-tr-n
+[node-atr]: https://docs.godotengine.org/en/stable/classes/class_node.html#class-node-method-atr
+[node-atr-n]: https://docs.godotengine.org/en/stable/classes/class_node.html#class-node-method-atr-n
+[domain-translate]: https://docs.godotengine.org/en/latest/classes/class_translationdomain.html#class-translationdomain-method-translate
+[domain-translate-plural]: https://docs.godotengine.org/en/latest/classes/class_translationdomain.html#class-translationdomain-method-translate-plural
+
 ## Development
 
 ### pre-commit

addons/block_code/block_code_node/block_code.gd

@@ -3,9 +3,15 @@
 class_name BlockCode
 extends Node
 
+const TxUtils := preload("res://addons/block_code/translation/utils.gd")
+
 @export var block_script: BlockScriptSerialization = null
 
 
+func _init():
+	TxUtils.set_block_translation_domain(self)
+
+
 func _ready():
 	if Engine.is_editor_hint():
 		return

addons/block_code/block_code_plugin.gd

@@ -4,6 +4,7 @@ extends EditorPlugin
 const MainPanelScene := preload("res://addons/block_code/ui/main_panel.tscn")
 const MainPanel = preload("res://addons/block_code/ui/main_panel.gd")
 const Types = preload("res://addons/block_code/types/types.gd")
+const TxUtils := preload("res://addons/block_code/translation/utils.gd")
 const ScriptWindow := preload("res://addons/block_code/ui/script_window/script_window.tscn")
 
 static var main_panel: MainPanel
@@ -12,6 +13,9 @@ static var block_code_button: Button
 const BlockInspectorPlugin := preload("res://addons/block_code/inspector_plugin/block_script_inspector.gd")
 var block_inspector_plugin: BlockInspectorPlugin
 
+const BlockTranslationParserPlugin := preload("res://addons/block_code/translation/parser.gd")
+var _tx_parser_plugin: BlockTranslationParserPlugin
+
 var editor_inspector: EditorInspector
 
 var _selected_block_code: BlockCode
@@ -29,6 +33,11 @@ const DISABLED_CLASSES := [
 ]
 
 
+func _init():
+	TxUtils.load_translations()
+	TxUtils.set_block_translation_domain(self)
+
+
 func _enter_tree():
 	Types.init_cast_graph()
 
@@ -41,6 +50,14 @@ func _enter_tree():
 	block_inspector_plugin = BlockInspectorPlugin.new()
 	add_inspector_plugin(block_inspector_plugin)
 
+	if not _tx_parser_plugin:
+		_tx_parser_plugin = BlockTranslationParserPlugin.new()
+	add_translation_parser_plugin(_tx_parser_plugin)
+
+	# Custom Project->Tools menu items.
+	add_tool_menu_item(tr("Regenerate %s POT file") % "BlockCode", TxUtils.regenerate_pot_file)
+	add_tool_menu_item(tr("Update %s translated files") % "BlockCode", TxUtils.update_pot_files)
+
 	# Remove unwanted class nodes from create node
 	old_feature_profile = EditorInterface.get_current_feature_profile()
 
@@ -69,6 +86,7 @@ func script_window_requested(script: String):
 
 
 func _exit_tree():
+	remove_translation_parser_plugin(_tx_parser_plugin)
 	remove_inspector_plugin(block_inspector_plugin)
 
 	if block_code_button:

addons/block_code/inspector_plugin/block_script_inspector.gd

@@ -1,6 +1,11 @@
 extends EditorInspectorPlugin
 
 const BlockCodePlugin = preload("res://addons/block_code/block_code_plugin.gd")
+const TxUtils := preload("res://addons/block_code/translation/utils.gd")
+
+
+func _init():
+	TxUtils.set_block_translation_domain(self)
 
 
 func _can_handle(object):
@@ -11,7 +16,7 @@ func _parse_begin(object):
 	var block_code := object as BlockCode
 
 	var button := Button.new()
-	button.text = "Open Block Script"
+	button.text = tr("Open Block Script")
 	button.pressed.connect(func(): BlockCodePlugin.main_panel.switch_block_code_node(block_code))
 
 	var container := MarginContainer.new()