Move context and plural support to Translation

- `TranslationPO` is now an empty class. It exists for compatibility.
- `OptimizedTranslation` stays the same, no context or plural support.

core/io/translation_loader_po.cpp

@@ -31,7 +31,7 @@
 #include "translation_loader_po.h"
 
 #include "core/io/file_access.h"
-#include "core/string/translation_po.h"
+#include "core/string/translation.h"
 
 Ref<Resource> TranslationLoaderPO::load_translation(Ref<FileAccess> f, Error *r_error) {
 	if (r_error) {
@@ -39,7 +39,8 @@ Ref<Resource> TranslationLoaderPO::load_translation(Ref<FileAccess> f, Error *r_
 	}
 
 	const String path = f->get_path();
-	Ref<TranslationPO> translation = Ref<TranslationPO>(memnew(TranslationPO));
+	Ref<Translation> translation;
+	translation.instantiate();
 	String config;
 
 	uint32_t magic = f->get_32();
@@ -229,7 +230,7 @@ Ref<Resource> TranslationLoaderPO::load_translation(Ref<FileAccess> f, Error *r_
 					if (p_start != -1) {
 						int p_end = config.find_char('\n', p_start);
 						translation->set_plural_rules_override(config.substr(p_start, p_end - p_start));
-						plural_forms = translation->get_plural_forms();
+						plural_forms = translation->get_nplurals();
 					}
 				}
 

core/io/translation_loader_po.h

@@ -32,7 +32,6 @@
 
 #include "core/io/file_access.h"
 #include "core/io/resource_loader.h"
-#include "core/string/translation.h"
 
 class TranslationLoaderPO : public ResourceFormatLoader {
 	GDSOFTCLASS(TranslationLoaderPO, ResourceFormatLoader);

core/string/optimized_translation.cpp

@@ -44,11 +44,27 @@ struct CompressedString {
 
 void OptimizedTranslation::generate(const Ref<Translation> &p_from) {
 	// This method compresses a Translation instance.
-	// Right now, it doesn't handle context or plurals, so Translation subclasses using plurals or context (i.e TranslationPO) shouldn't be compressed.
+	// Right now, it doesn't handle context or plurals.
 #ifdef TOOLS_ENABLED
 	ERR_FAIL_COND(p_from.is_null());
+
 	List<StringName> keys;
-	p_from->get_message_list(&keys);
+	{
+		List<StringName> raw_keys;
+		p_from->get_message_list(&raw_keys);
+
+		for (const StringName &key : raw_keys) {
+			const String key_str = key.operator String();
+			int p = key_str.find_char(0x04);
+			if (p == -1) {
+				keys.push_back(key);
+			} else {
+				const String &msgctxt = key_str.substr(0, p);
+				const String &msgid = key_str.substr(p + 1);
+				WARN_PRINT(vformat("OptimizedTranslation does not support context, ignoring message '%s' with context '%s'.", msgid, msgctxt));
+			}
+		}
+	}
 
 	int size = Math::larger_prime(keys.size());
 

core/string/translation.cpp

@@ -34,42 +34,102 @@
 #include "core/string/plural_rules.h"
 #include "core/string/translation_server.h"
 
+void _check_for_incompatibility(const String &p_msgctxt, const String &p_msgid) {
+	// Gettext PO and MO files use an empty untranslated string without context
+	// to store metadata.
+	if (p_msgctxt.is_empty() && p_msgid.is_empty()) {
+		WARN_PRINT("Both context and the untranslated string are empty. This may cause issues with the translation system and external tools.");
+	}
+
+	// The EOT character (0x04) is used as a separator between context and
+	// untranslated string in the MO file format. This convention is also used
+	// by `get_message_list()`.
+	//
+	// It's unusual to have this character in the context or untranslated
+	// string. But it doesn't do any harm as long as you are aware of this when
+	// using the relevant APIs and tools.
+	if (p_msgctxt.contains_char(0x04)) {
+		WARN_PRINT(vformat("Found EOT character (0x04) within context '%s'. This may cause issues with the translation system and external tools.", p_msgctxt));
+	}
+	if (p_msgid.contains_char(0x04)) {
+		WARN_PRINT(vformat("Found EOT character (0x04) within untranslated string '%s'. This may cause issues with the translation system and external tools.", p_msgid));
+	}
+}
+
 Dictionary Translation::_get_messages() const {
 	Dictionary d;
-	for (const KeyValue<StringName, StringName> &E : translation_map) {
+	for (const KeyValue<MessageKey, Vector<StringName>> &E : translation_map) {
-		d[E.key] = E.value;
+		const Array &storage_key = { E.key.msgctxt, E.key.msgid };
+
+		Array storage_value;
+		storage_value.resize(E.value.size());
+		for (int i = 0; i < E.value.size(); i++) {
+			storage_value[i] = E.value[i];
+		}
+		d[storage_key] = storage_value;
 	}
 	return d;
 }
 
-Vector<String> Translation::_get_message_list() const {
+void Translation::_set_messages(const Dictionary &p_messages) {
-	Vector<String> msgs;
+	translation_map.clear();
-	msgs.resize(translation_map.size());
-	int idx = 0;
-	for (const KeyValue<StringName, StringName> &E : translation_map) {
-		msgs.set(idx, E.key);
-		idx += 1;
-	}
 
-	return msgs;
+	for (const KeyValue<Variant, Variant> &kv : p_messages) {
+		switch (kv.key.get_type()) {
+			// Old version, no context or plural support.
+			case Variant::STRING_NAME: {
+				const MessageKey msg_key = { StringName(), kv.key };
+				_check_for_incompatibility(msg_key.msgctxt, msg_key.msgid);
+				translation_map[msg_key] = { kv.value };
+			} break;
+
+			// Current version.
+			case Variant::ARRAY: {
+				const Array &storage_key = kv.key;
+				const MessageKey msg_key = { storage_key[0], storage_key[1] };
+
+				const Array &storage_value = kv.value;
+				ERR_CONTINUE_MSG(storage_value.is_empty(), vformat("No translated strings for untranslated string '%s' with context '%s'.", msg_key.msgid, msg_key.msgctxt));
+
+				Vector<StringName> msgstrs;
+				msgstrs.resize(storage_value.size());
+				for (int i = 0; i < storage_value.size(); i++) {
+					msgstrs.write[i] = storage_value[i];
+				}
+
+				_check_for_incompatibility(msg_key.msgctxt, msg_key.msgid);
+				translation_map[msg_key] = msgstrs;
+			} break;
+
+			default: {
+				WARN_PRINT(vformat("Invalid key type in messages dictionary: %s.", Variant::get_type_name(kv.key.get_type())));
+				continue;
+			}
+		}
+	}
+}
+
+Vector<String> Translation::_get_message_list() const {
+	List<StringName> msgstrs;
+	get_message_list(&msgstrs);
+
+	Vector<String> keys;
+	keys.resize(msgstrs.size());
+	int idx = 0;
+	for (const StringName &msgstr : msgstrs) {
+		keys.write[idx++] = msgstr;
+	}
+	return keys;
 }
 
 Vector<String> Translation::get_translated_message_list() const {
-	Vector<String> msgs;
+	Vector<String> msgstrs;
-	msgs.resize(translation_map.size());
+	for (const KeyValue<MessageKey, Vector<StringName>> &E : translation_map) {
-	int idx = 0;
+		for (const StringName &msgstr : E.value) {
-	for (const KeyValue<StringName, StringName> &E : translation_map) {
+			msgstrs.push_back(msgstr);
-		msgs.set(idx, E.value);
+		}
-		idx += 1;
-	}
-
-	return msgs;
-}
-
-void Translation::_set_messages(const Dictionary &p_messages) {
-	for (const KeyValue<Variant, Variant> &kv : p_messages) {
-		translation_map[kv.key] = kv.value;
 	}
+	return msgstrs;
 }
 
 void Translation::set_locale(const String &p_locale) {
@@ -82,13 +142,21 @@ void Translation::set_locale(const String &p_locale) {
 }
 
 void Translation::add_message(const StringName &p_src_text, const StringName &p_xlated_text, const StringName &p_context) {
-	translation_map[p_src_text] = p_xlated_text;
+	_check_for_incompatibility(p_context, p_src_text);
+	translation_map[{ p_context, p_src_text }] = { p_xlated_text };
 }
 
 void Translation::add_plural_message(const StringName &p_src_text, const Vector<String> &p_plural_xlated_texts, const StringName &p_context) {
-	WARN_PRINT("Translation class doesn't handle plural messages. Calling add_plural_message() on a Translation instance is probably a mistake. \nUse a derived Translation class that handles plurals, such as TranslationPO class");
 	ERR_FAIL_COND_MSG(p_plural_xlated_texts.is_empty(), "Parameter vector p_plural_xlated_texts passed in is empty.");
-	translation_map[p_src_text] = p_plural_xlated_texts[0];
+
+	Vector<StringName> msgstrs;
+	msgstrs.resize(p_plural_xlated_texts.size());
+	for (int i = 0; i < p_plural_xlated_texts.size(); i++) {
+		msgstrs.write[i] = p_plural_xlated_texts[i];
+	}
+
+	_check_for_incompatibility(p_context, p_src_text);
+	translation_map[{ p_context, p_src_text }] = msgstrs;
 }
 
 StringName Translation::get_message(const StringName &p_src_text, const StringName &p_context) const {
@@ -97,16 +165,13 @@ StringName Translation::get_message(const StringName &p_src_text, const StringNa
 		return ret;
 	}
 
-	if (p_context != StringName()) {
+	const Vector<StringName> *msgstrs = translation_map.getptr({ p_context, p_src_text });
-		WARN_PRINT("Translation class doesn't handle context. Using context in get_message() on a Translation instance is probably a mistake. \nUse a derived Translation class that handles context, such as TranslationPO class");
+	if (msgstrs == nullptr) {
-	}
-
-	HashMap<StringName, StringName>::ConstIterator E = translation_map.find(p_src_text);
-	if (!E) {
 		return StringName();
 	}
 
-	return E->value;
+	DEV_ASSERT(!msgstrs->is_empty()); // Should be prevented when adding messages.
+	return msgstrs->get(0);
 }
 
 StringName Translation::get_plural_message(const StringName &p_src_text, const StringName &p_plural_text, int p_n, const StringName &p_context) const {
@@ -115,21 +180,30 @@ StringName Translation::get_plural_message(const StringName &p_src_text, const S
 		return ret;
 	}
 
-	WARN_PRINT("Translation class doesn't handle plural messages. Calling get_plural_message() on a Translation instance is probably a mistake. \nUse a derived Translation class that handles plurals, such as TranslationPO class");
+	ERR_FAIL_COND_V_MSG(p_n < 0, StringName(), "N passed into translation to get a plural message should not be negative. For negative numbers, use singular translation please. Search \"gettext PO Plural Forms\" online for details on translating negative numbers.");
-	return get_message(p_src_text);
+
+	const Vector<StringName> *msgstrs = translation_map.getptr({ p_context, p_src_text });
+	if (msgstrs == nullptr) {
+		return StringName();
+	}
+
+	const int index = _get_plural_rules()->evaluate(p_n);
+	ERR_FAIL_INDEX_V_MSG(index, msgstrs->size(), StringName(), "Plural index returned or number of plural translations is not valid.");
+	return msgstrs->get(index);
 }
 
 void Translation::erase_message(const StringName &p_src_text, const StringName &p_context) {
-	if (p_context != StringName()) {
+	translation_map.erase({ p_context, p_src_text });
-		WARN_PRINT("Translation class doesn't handle context. Using context in erase_message() on a Translation instance is probably a mistake. \nUse a derived Translation class that handles context, such as TranslationPO class");
-	}
-
-	translation_map.erase(p_src_text);
 }
 
 void Translation::get_message_list(List<StringName> *r_messages) const {
-	for (const KeyValue<StringName, StringName> &E : translation_map) {
+	for (const KeyValue<MessageKey, Vector<StringName>> &E : translation_map) {
-		r_messages->push_back(E.key);
+		if (E.key.msgctxt.is_empty()) {
+			r_messages->push_back(E.key.msgid);
+		} else {
+			// Separated by the EOT character. Compatible with the MO file format.
+			r_messages->push_back(vformat("%s\x04%s", E.key.msgctxt, E.key.msgid));
+		}
 	}
 }
 
@@ -175,6 +249,10 @@ String Translation::get_plural_rules_override() const {
 	return plural_rules_override;
 }
 
+int Translation::get_nplurals() const {
+	return _get_plural_rules()->get_nplurals();
+}
+
 void Translation::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_locale", "locale"), &Translation::set_locale);
 	ClassDB::bind_method(D_METHOD("get_locale"), &Translation::get_locale);
@@ -195,7 +273,7 @@ void Translation::_bind_methods() {
 	GDVIRTUAL_BIND(_get_message, "src_message", "context");
 
 	ADD_PROPERTY(PropertyInfo(Variant::DICTIONARY, "messages", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL), "_set_messages", "_get_messages");
-	ADD_PROPERTY(PropertyInfo(Variant::STRING, "locale"), "set_locale", "get_locale");
+	ADD_PROPERTY(PropertyInfo(Variant::STRING, "locale", PROPERTY_HINT_LOCALE_ID), "set_locale", "get_locale");
 	ADD_PROPERTY(PropertyInfo(Variant::STRING, "plural_rules_override"), "set_plural_rules_override", "get_plural_rules_override");
 }
 

core/string/translation.h

@@ -41,12 +41,29 @@ class Translation : public Resource {
 	RES_BASE_EXTENSION("translation");
 
 	String locale = "en";
-	HashMap<StringName, StringName> translation_map;
+
+	struct MessageKey {
+		StringName msgctxt;
+		StringName msgid;
+
+		// Required to use this struct as a key in HashMap.
+		static uint32_t hash(const MessageKey &p_key) {
+			uint32_t h = hash_murmur3_one_32(HashMapHasherDefault::hash(p_key.msgctxt));
+			return hash_fmix32(hash_murmur3_one_32(HashMapHasherDefault::hash(p_key.msgid), h));
+		}
+		bool operator==(const MessageKey &p_key) const {
+			return msgctxt == p_key.msgctxt && msgid == p_key.msgid;
+		}
+	};
+
+	HashMap<MessageKey, Vector<StringName>, MessageKey> translation_map;
 
 	mutable PluralRules *plural_rules_cache = nullptr;
 	String plural_rules_override;
 
 	virtual Vector<String> _get_message_list() const;
+
+	// For data storage.
 	virtual Dictionary _get_messages() const;
 	virtual void _set_messages(const Dictionary &p_messages);
 
@@ -74,5 +91,8 @@ public:
 	void set_plural_rules_override(const String &p_rules);
 	String get_plural_rules_override() const;
 
+	// This method is not exposed to scripting intentionally. It is only used by TranslationLoaderPO and tests.
+	int get_nplurals() const;
+
 	~Translation();
 };

core/string/translation_po.cpp

@@ -30,198 +30,5 @@
 
 #include "translation_po.h"
 
-#include "core/string/plural_rules.h"
+// This file is intentionally left empty.
-
+// It makes sure that `TranslationPO` exists, for compatibility.
-#ifdef DEBUG_TRANSLATION_PO
-#include "core/io/file_access.h"
-
-void TranslationPO::print_translation_map() {
-	Error err;
-	Ref<FileAccess> file = FileAccess::open("translation_map_print_test.txt", FileAccess::WRITE, &err);
-	if (err != OK) {
-		ERR_PRINT("Failed to open translation_map_print_test.txt");
-		return;
-	}
-
-	file->store_line("NPlural : " + String::num_int64(get_plural_forms()));
-	file->store_line("Plural rule : " + get_plural_rule());
-	file->store_line("");
-
-	List<StringName> context_l;
-	translation_map.get_key_list(&context_l);
-	for (const StringName &ctx : context_l) {
-		file->store_line(" ===== Context: " + String::utf8(String(ctx).utf8()) + " ===== ");
-		const HashMap<StringName, Vector<StringName>> &inner_map = translation_map[ctx];
-
-		List<StringName> id_l;
-		inner_map.get_key_list(&id_l);
-		for (const StringName &id : id_l) {
-			file->store_line("msgid: " + String::utf8(String(id).utf8()));
-			for (int i = 0; i < inner_map[id].size(); i++) {
-				file->store_line("msgstr[" + String::num_int64(i) + "]: " + String::utf8(String(inner_map[id][i]).utf8()));
-			}
-			file->store_line("");
-		}
-	}
-}
-#endif
-
-Dictionary TranslationPO::_get_messages() const {
-	// Return translation_map as a Dictionary.
-
-	Dictionary d;
-
-	for (const KeyValue<StringName, HashMap<StringName, Vector<StringName>>> &E : translation_map) {
-		Dictionary d2;
-
-		for (const KeyValue<StringName, Vector<StringName>> &E2 : E.value) {
-			d2[E2.key] = E2.value;
-		}
-
-		d[E.key] = d2;
-	}
-
-	return d;
-}
-
-void TranslationPO::_set_messages(const Dictionary &p_messages) {
-	// Construct translation_map from a Dictionary.
-
-	for (const KeyValue<Variant, Variant> &kv : p_messages) {
-		const Dictionary &id_str_map = kv.value;
-
-		HashMap<StringName, Vector<StringName>> temp_map;
-		for (const KeyValue<Variant, Variant> &kv_id : id_str_map) {
-			StringName id = kv_id.key;
-			temp_map[id] = kv_id.value;
-		}
-
-		translation_map[kv.key] = temp_map;
-	}
-}
-
-Vector<String> TranslationPO::get_translated_message_list() const {
-	Vector<String> msgs;
-	for (const KeyValue<StringName, HashMap<StringName, Vector<StringName>>> &E : translation_map) {
-		if (E.key != StringName()) {
-			continue;
-		}
-
-		for (const KeyValue<StringName, Vector<StringName>> &E2 : E.value) {
-			for (const StringName &E3 : E2.value) {
-				msgs.push_back(E3);
-			}
-		}
-	}
-
-	return msgs;
-}
-
-Vector<String> TranslationPO::_get_message_list() const {
-	// Return all keys in translation_map.
-
-	List<StringName> msgs;
-	get_message_list(&msgs);
-
-	Vector<String> v;
-	for (const StringName &E : msgs) {
-		v.push_back(E);
-	}
-
-	return v;
-}
-
-void TranslationPO::add_message(const StringName &p_src_text, const StringName &p_xlated_text, const StringName &p_context) {
-	HashMap<StringName, Vector<StringName>> &map_id_str = translation_map[p_context];
-
-	if (map_id_str.has(p_src_text)) {
-		WARN_PRINT(vformat("Double translations for \"%s\" under the same context \"%s\" for locale \"%s\".\nThere should only be one unique translation for a given string under the same context.", String(p_src_text), String(p_context), get_locale()));
-		map_id_str[p_src_text].set(0, p_xlated_text);
-	} else {
-		map_id_str[p_src_text].push_back(p_xlated_text);
-	}
-}
-
-void TranslationPO::add_plural_message(const StringName &p_src_text, const Vector<String> &p_plural_xlated_texts, const StringName &p_context) {
-	ERR_FAIL_COND_MSG(p_plural_xlated_texts.size() != _get_plural_rules()->get_nplurals(), vformat("Trying to add plural texts that don't match the required number of plural forms for locale \"%s\".", get_locale()));
-
-	HashMap<StringName, Vector<StringName>> &map_id_str = translation_map[p_context];
-
-	if (map_id_str.has(p_src_text)) {
-		WARN_PRINT(vformat("Double translations for \"%s\" under the same context \"%s\" for locale %s.\nThere should only be one unique translation for a given string under the same context.", p_src_text, p_context, get_locale()));
-		map_id_str[p_src_text].clear();
-	}
-
-	for (int i = 0; i < p_plural_xlated_texts.size(); i++) {
-		map_id_str[p_src_text].push_back(p_plural_xlated_texts[i]);
-	}
-}
-
-int TranslationPO::get_plural_forms() const {
-	return _get_plural_rules()->get_nplurals();
-}
-
-String TranslationPO::get_plural_rule() const {
-	return _get_plural_rules()->get_plural();
-}
-
-StringName TranslationPO::get_message(const StringName &p_src_text, const StringName &p_context) const {
-	if (!translation_map.has(p_context) || !translation_map[p_context].has(p_src_text)) {
-		return StringName();
-	}
-	ERR_FAIL_COND_V_MSG(translation_map[p_context][p_src_text].is_empty(), StringName(), vformat("Source text \"%s\" is registered but doesn't have a translation. Please report this bug.", String(p_src_text)));
-
-	return translation_map[p_context][p_src_text][0];
-}
-
-StringName TranslationPO::get_plural_message(const StringName &p_src_text, const StringName &p_plural_text, int p_n, const StringName &p_context) const {
-	ERR_FAIL_COND_V_MSG(p_n < 0, StringName(), "N passed into translation to get a plural message should not be negative. For negative numbers, use singular translation please. Search \"gettext PO Plural Forms\" online for the documentation on translating negative numbers.");
-
-	if (!translation_map.has(p_context) || !translation_map[p_context].has(p_src_text)) {
-		return StringName();
-	}
-	ERR_FAIL_COND_V_MSG(translation_map[p_context][p_src_text].is_empty(), StringName(), vformat("Source text \"%s\" is registered but doesn't have a translation. Please report this bug.", String(p_src_text)));
-
-	int plural_index = _get_plural_rules()->evaluate(p_n);
-	ERR_FAIL_COND_V_MSG(plural_index < 0 || translation_map[p_context][p_src_text].size() < plural_index + 1, StringName(), "Plural index returned or number of plural translations is not valid. Please report this bug.");
-
-	return translation_map[p_context][p_src_text][plural_index];
-}
-
-void TranslationPO::erase_message(const StringName &p_src_text, const StringName &p_context) {
-	if (!translation_map.has(p_context)) {
-		return;
-	}
-
-	translation_map[p_context].erase(p_src_text);
-}
-
-void TranslationPO::get_message_list(List<StringName> *r_messages) const {
-	// OptimizedTranslation uses this function to get the list of msgid.
-	// Return all the keys of translation_map under "" context.
-
-	for (const KeyValue<StringName, HashMap<StringName, Vector<StringName>>> &E : translation_map) {
-		if (E.key != StringName()) {
-			continue;
-		}
-
-		for (const KeyValue<StringName, Vector<StringName>> &E2 : E.value) {
-			r_messages->push_back(E2.key);
-		}
-	}
-}
-
-int TranslationPO::get_message_count() const {
-	int count = 0;
-
-	for (const KeyValue<StringName, HashMap<StringName, Vector<StringName>>> &E : translation_map) {
-		count += E.value.size();
-	}
-
-	return count;
-}
-
-void TranslationPO::_bind_methods() {
-	ClassDB::bind_method(D_METHOD("get_plural_forms"), &TranslationPO::get_plural_forms);
-	ClassDB::bind_method(D_METHOD("get_plural_rule"), &TranslationPO::get_plural_rule);
-}

core/string/translation_po.h

@@ -30,41 +30,8 @@
 
 #pragma once
 
-//#define DEBUG_TRANSLATION_PO
-
 #include "core/string/translation.h"
 
 class TranslationPO : public Translation {
 	GDCLASS(TranslationPO, Translation);
-
-	// TLDR: Maps context to a list of source strings and translated strings. In PO terms, maps msgctxt to a list of msgid and msgstr.
-	// The first key corresponds to context, and the second key (of the contained HashMap) corresponds to source string.
-	// The value Vector<StringName> in the second map stores the translated strings. Index 0, 1, 2 matches msgstr[0], msgstr[1], msgstr[2]... in the case of plurals.
-	// Otherwise index 0 matches to msgstr in a singular translation.
-	// Strings without context have "" as first key.
-	HashMap<StringName, HashMap<StringName, Vector<StringName>>> translation_map;
-
-	Vector<String> _get_message_list() const override;
-	Dictionary _get_messages() const override;
-	void _set_messages(const Dictionary &p_messages) override;
-
-protected:
-	static void _bind_methods();
-
-public:
-	Vector<String> get_translated_message_list() const override;
-	void get_message_list(List<StringName> *r_messages) const override;
-	int get_message_count() const override;
-	void add_message(const StringName &p_src_text, const StringName &p_xlated_text, const StringName &p_context = "") override;
-	void add_plural_message(const StringName &p_src_text, const Vector<String> &p_plural_xlated_texts, const StringName &p_context = "") override;
-	StringName get_message(const StringName &p_src_text, const StringName &p_context = "") const override;
-	StringName get_plural_message(const StringName &p_src_text, const StringName &p_plural_text, int p_n, const StringName &p_context = "") const override;
-	void erase_message(const StringName &p_src_text, const StringName &p_context = "") override;
-
-	int get_plural_forms() const;
-	String get_plural_rule() const;
-
-#ifdef DEBUG_TRANSLATION_PO
-	void print_translation_map();
-#endif
 };

doc/classes/Translation.xml

@@ -4,7 +4,8 @@
 		A language translation that maps a collection of strings to their individual translations.
 	</brief_description>
 	<description>
-		[Translation]s are resources that can be loaded and unloaded on demand. They map a collection of strings to their individual translations, and they also provide convenience methods for pluralization.
+		[Translation] maps a collection of strings to their individual translations, and also provides convenience methods for pluralization.
+		A [Translation] consists of messages. A message is identified by its context and untranslated string. Unlike [url=https://www.gnu.org/software/gettext/]gettext[/url], using an empty context string in Godot means not using any context.
 	</description>
 	<tutorials>
 		<link title="Internationalizing games">$DOCS_URL/tutorials/i18n/internationalizing_games.html</link>
@@ -48,7 +49,6 @@
 			<description>
 				Adds a message involving plural translation if nonexistent, followed by its translation.
 				An additional context could be used to specify the translation context or differentiate polysemic words.
-				[b]Note:[/b] Plurals are only supported in [url=$DOCS_URL/tutorials/i18n/localization_using_gettext.html]gettext-based translations (PO)[/url], not CSV.
 			</description>
 		</method>
 		<method name="erase_message">
@@ -76,7 +76,19 @@
 		<method name="get_message_list" qualifiers="const">
 			<return type="PackedStringArray" />
 			<description>
-				Returns all the messages (keys).
+				Returns the keys of all messages, that is, the context and untranslated strings of each message.
+				[b]Note:[/b] If a message does not use a context, the corresponding element is the untranslated string. Otherwise, the corresponding element is the context and untranslated string separated by the EOT character ([code]U+0004[/code]). This is done for compatibility purposes.
+				[codeblock]
+				for key in translation.get_message_list():
+					var p = key.find("\u0004")
+					if p == -1:
+						var untranslated = key
+						print("Message %s" % untranslated)
+					else:
+						var context = key.substr(0, p)
+						var untranslated = key.substr(p + 1)
+						print("Message %s with context %s" % [untranslated, context])
+				[/codeblock]
 			</description>
 		</method>
 		<method name="get_plural_message" qualifiers="const">
@@ -94,7 +106,7 @@
 		<method name="get_translated_message_list" qualifiers="const">
 			<return type="PackedStringArray" />
 			<description>
-				Returns all the messages (translated text).
+				Returns all the translated strings.
 			</description>
 		</method>
 	</methods>

tests/core/string/test_translation.h

@@ -33,7 +33,6 @@
 #include "core/string/optimized_translation.h"
 #include "core/string/plural_rules.h"
 #include "core/string/translation.h"
-#include "core/string/translation_po.h"
 #include "core/string/translation_server.h"
 
 #ifdef TOOLS_ENABLED
@@ -46,7 +45,8 @@
 namespace TestTranslation {
 
 TEST_CASE("[Translation] Messages") {
-	Ref<Translation> translation = memnew(Translation);
+	Ref<Translation> translation;
+	translation.instantiate();
 	translation->set_locale("fr");
 	translation->add_message("Hello", "Bonjour");
 	CHECK(translation->get_message("Hello") == "Bonjour");
@@ -71,8 +71,9 @@ TEST_CASE("[Translation] Messages") {
 	CHECK(messages.find("Hello3"));
 }
 
-TEST_CASE("[TranslationPO] Messages with context") {
+TEST_CASE("[Translation] Messages with context") {
-	Ref<TranslationPO> translation = memnew(TranslationPO);
+	Ref<Translation> translation;
+	translation.instantiate();
 	translation->set_locale("fr");
 	translation->add_message("Hello", "Bonjour");
 	translation->add_message("Hello", "Salut", "friendly");
@@ -90,11 +91,8 @@ TEST_CASE("[TranslationPO] Messages with context") {
 	List<StringName> messages;
 	translation->get_message_list(&messages);
 
-	// `get_message_count()` takes all contexts into account.
 	CHECK(translation->get_message_count() == 1);
-	// Only the default context is taken into account.
+	CHECK(messages.size() == 1);
-	// Since "Hello" is now only present in a non-default context, it is not counted in the list of messages.
-	CHECK(messages.size() == 0);
 
 	translation->add_message("Hello2", "Bonjour2");
 	translation->add_message("Hello2", "Salut2", "friendly");
@@ -102,35 +100,35 @@ TEST_CASE("[TranslationPO] Messages with context") {
 	messages.clear();
 	translation->get_message_list(&messages);
 
-	// `get_message_count()` takes all contexts into account.
 	CHECK(translation->get_message_count() == 4);
-	// Only the default context is taken into account.
+	CHECK(messages.size() == 4);
-	CHECK(messages.size() == 2);
 	// Messages are stored in a Map, don't assume ordering.
 	CHECK(messages.find("Hello2"));
 	CHECK(messages.find("Hello3"));
+	// Context and untranslated string are separated by EOT.
+	CHECK(messages.find("friendly\x04Hello2"));
 }
 
-TEST_CASE("[TranslationPO] Plural messages") {
+TEST_CASE("[Translation] Plural messages") {
 	{
-		Ref<TranslationPO> translation = memnew(TranslationPO);
+		Ref<Translation> translation;
+		translation.instantiate();
 		translation->set_locale("fr");
-		CHECK(translation->get_plural_forms() == 3);
+		CHECK(translation->get_nplurals() == 3);
-		CHECK(translation->get_plural_rule() == "(n == 0 || n == 1) ? 0 : n != 0 && n % 1000000 == 0 ? 1 : 2)");
 	}
 
 	{
-		Ref<TranslationPO> translation = memnew(TranslationPO);
+		Ref<Translation> translation;
+		translation.instantiate();
 		translation->set_locale("invalid");
-		CHECK(translation->get_plural_forms() == 2);
+		CHECK(translation->get_nplurals() == 2);
-		CHECK(translation->get_plural_rule() == "(n != 1)");
 	}
 
 	{
-		Ref<TranslationPO> translation = memnew(TranslationPO);
+		Ref<Translation> translation;
+		translation.instantiate();
 		translation->set_plural_rules_override("Plural-Forms: nplurals=2; plural=(n >= 2);");
-		CHECK(translation->get_plural_forms() == 2);
+		CHECK(translation->get_nplurals() == 2);
-		CHECK(translation->get_plural_rule() == "(n >= 2)");
 
 		PackedStringArray plurals;
 		plurals.push_back("Il y a %d pomme");
@@ -146,7 +144,7 @@ TEST_CASE("[TranslationPO] Plural messages") {
 	}
 }
 
-TEST_CASE("[TranslationPO] Plural rules parsing") {
+TEST_CASE("[Translation] Plural rules parsing") {
 	ERR_PRINT_OFF;
 	{
 		CHECK(PluralRules::parse("") == nullptr);