Add: action0 prop 21 for rail stations

Author: Rito13

nml/actions/action0properties.py

@@ -818,10 +818,15 @@ def station_tile_flags(value):
     ]
 
 
-def station_minimum_bridge_height(value):
-    if not isinstance(value, Array):
-        raise generic.ScriptError("Flag list must be an array", value.pos)
-    return [VariableByteListProp(0x20, [[flags.reduce_constant().value for flags in value.values]], True)]
+def array_for_station_properties(prop_num, list_type="Flag"):
+    def __call__(value):
+        if not isinstance(value, Array):
+            raise generic.ScriptError(list_type + " list must be an array", value.pos)
+        if len(value.values) % 2 != 0:
+            generic.print_warning(generic.Warning.GENERIC, list_type + " list does not have even length", 0)
+        return [VariableByteListProp(prop_num, [[flags.reduce_constant().value for flags in value.values]], True)]
+
+    return __call__
 
 
 # fmt: off
@@ -849,7 +854,8 @@ def station_minimum_bridge_height(value):
     "name":                  {"size": 2, "num": (256, -1, 0x1C), "string": (256, 0xC5, 0xDC), "required": True},
     "classname":             {"size": 2, "num": (256, -1, 0x1D), "string": (256, 0xC4, 0xDC)},
     "tile_flags":            {"custom_function": station_tile_flags},  # = prop 1E
-    "minimum_bridge_height": {"custom_function": station_minimum_bridge_height},  # = prop 20
+    "minimum_bridge_height": {"custom_function": array_for_station_properties(0x20, list_type="Bridge heights")},
+    "bridge_pillars_flags":  {"custom_function": array_for_station_properties(0x21)},
 }
 # fmt: on