Add advanced string format

Cherry-pick from #7010

core/ustring.cpp

@@ -2776,6 +2776,78 @@ bool String::matchn(const String &p_wildcard) const {
 	return _wildcard_match(p_wildcard.c_str(), c_str(), false);
 }
 
+String String::format(const Variant &values, String placeholder) const {
+
+	String new_string = String(this->ptr());
+
+	if (values.get_type() == Variant::ARRAY) {
+		Array values_arr = values;
+
+		for (int i = 0; i < values_arr.size(); i++) {
+			String i_as_str = String::num_int64(i);
+
+			if (values_arr[i].get_type() == Variant::ARRAY) { //Array in Array structure [["name","RobotGuy"],[0,"godot"],["strength",9000.91]]
+				Array value_arr = values_arr[i];
+
+				if (value_arr.size() == 2) {
+					Variant v_key = value_arr[0];
+					String key;
+
+					key = v_key.get_construct_string();
+					if (key.left(1) == "\"" && key.right(key.length() - 1) == "\"") {
+						key = key.substr(1, key.length() - 2);
+					}
+
+					Variant v_val = value_arr[1];
+					String val;
+					val = v_val.get_construct_string();
+
+					if (val.left(1) == "\"" && val.right(val.length() - 1) == "\"") {
+						val = val.substr(1, val.length() - 2);
+					}
+
+					new_string = new_string.replacen(placeholder.replace("_", key), val);
+				} else {
+					ERR_PRINT(String("STRING.format Inner Array size != 2 ").ascii().get_data());
+				}
+			} else { //Array structure ["RobotGuy","Logis","rookie"]
+				Variant v_val = values_arr[i];
+				String val;
+				val = v_val.get_construct_string();
+
+				if (val.left(1) == "\"" && val.right(val.length() - 1) == "\"") {
+					val = val.substr(1, val.length() - 2);
+				}
+
+				new_string = new_string.replacen(placeholder.replace("_", i_as_str), val);
+			}
+		}
+	} else if (values.get_type() == Variant::DICTIONARY) {
+		Dictionary d = values;
+		List<Variant> keys;
+		d.get_key_list(&keys);
+
+		for (List<Variant>::Element *E = keys.front(); E; E = E->next()) {
+			String key = E->get().get_construct_string();
+			String val = d[E->get()].get_construct_string();
+
+			if (key.left(1) == "\"" && key.right(key.length() - 1) == "\"") {
+				key = key.substr(1, key.length() - 2);
+			}
+
+			if (val.left(1) == "\"" && val.right(val.length() - 1) == "\"") {
+				val = val.substr(1, val.length() - 2);
+			}
+
+			new_string = new_string.replacen(placeholder.replace("_", key), val);
+		}
+	} else {
+		ERR_PRINT(String("Invalid type: use Array or Dictionary.").ascii().get_data());
+	}
+
+	return new_string;
+}
+
 String String::replace(String p_key, String p_with) const {
 
 	String new_string;

core/ustring.h

@@ -120,6 +120,7 @@ public:
 	bool is_subsequence_ofi(const String &p_string) const;
 	Vector<String> bigrams() const;
 	float similarity(const String &p_string) const;
+	String format(const Variant& values, String placeholder = "{_}") const;
 	String replace_first(String p_key, String p_with) const;
 	String replace(String p_key, String p_with) const;
 	String replacen(String p_key, String p_with) const;

core/variant_call.cpp

@@ -241,6 +241,7 @@ struct _VariantCall {
 	VCALL_LOCALMEM1R(String, is_subsequence_ofi);
 	VCALL_LOCALMEM0R(String, bigrams);
 	VCALL_LOCALMEM1R(String, similarity);
+	VCALL_LOCALMEM2R(String, format);
 	VCALL_LOCALMEM2R(String, replace);
 	VCALL_LOCALMEM2R(String, replacen);
 	VCALL_LOCALMEM2R(String, insert);
@@ -1317,6 +1318,7 @@ void register_variant_methods() {
 	ADDFUNC0(STRING, STRING_ARRAY, String, bigrams, varray());
 	ADDFUNC1(STRING, REAL, String, similarity, STRING, "text", varray());
 
+	ADDFUNC2(STRING, STRING, String, format, NIL, "values", STRING, "placeholder", varray("{_}"));
 	ADDFUNC2(STRING, STRING, String, replace, STRING, "what", STRING, "forwhat", varray());
 	ADDFUNC2(STRING, STRING, String, replacen, STRING, "what", STRING, "forwhat", varray());
 	ADDFUNC2(STRING, STRING, String, insert, INT, "pos", STRING, "what", varray());