Add explanation of date accessors in long description

Core/GDCore/Extensions/Builtin/TimeExtension.cpp

@@ -227,12 +227,14 @@ void GD_CORE_API BuiltinExtensionsImplementer::ImplementsTimeExtension(
       .AddCodeOnlyParameter("currentScene", "")
       .AddParameter(
           "stringWithSelector",
+          _("Date part"),
+          "[\"hour\", \"min\", \"sec\", \"mon\", \"year\", \"fullyear\", "
+          "\"wday\", \"mday\", \"yday\", \"timestamp\"]")
+      .SetParameterLongDescription(
           _("Hour: hour - Minutes: min - Seconds: sec - Day of month: "
-            "mday - Months since January: mon - Year since 1900: year - Days "
-            "since Sunday: wday - Days since Jan 1st: yday - Timestamp (ms): "
-            "timestamp\""),
-          "[\"hour\", \"min\", \"sec\", \"mon\", \"year\", \"wday\", \"mday\", "
-          "\"yday\", \"timestamp\"]");
+            "mday - Months since January (January being 0): mon - Year: "
+            "fullyear - Year since 1900: year - Days since Sunday: wday - Days "
+            "since Jan 1st: yday - Timestamp (ms): timestamp\""));
 }
 
 }  // namespace gd

GDJS/Runtime/events-tools/runtimescenetools.ts

@@ -221,6 +221,8 @@ namespace gdjs {
           return now.getDate();
         } else if (what === 'mon') {
           return now.getMonth();
+        } else if (what === 'fullyear') {
+          return now.getFullYear();
         } else if (what === 'year') {
           //Conform to the C way of returning years.
           return now.getFullYear() - 1900;