fixed incorrect recognition of some NULL objects

src/main/java/carpet/script/api/WorldAccess.java

@@ -375,7 +375,7 @@ public class WorldAccess {
             if (lv.size() < locator.offset) throw new InternalExpressionException("'set_poi' requires the new poi type or null, after position argument");
             Value poi = lv.get(locator.offset+0).evalValue(c);
             PointOfInterestStorage store = cc.s.getWorld().getPointOfInterestStorage();
-            if (poi == Value.NULL)
+            if (poi.isNull())
             {   // clear poi information
                 if (store.getType(pos).isPresent())
                 {

src/main/java/carpet/script/value/EntityValue.java

@@ -1113,7 +1113,7 @@ public class EntityValue extends Value
         put("breaking_progress", (e, a) -> {
             if (e instanceof ServerPlayerEntity)
             {
-                int progress = (a == null || a == Value.NULL)?-1:NumericValue.asNumber(a).getInt();
+                int progress = (a == null || a.isNull())?-1:NumericValue.asNumber(a).getInt();
                 ServerPlayerInteractionManagerInterface manager = (ServerPlayerInteractionManagerInterface) (((ServerPlayerEntity) e).interactionManager);
                 manager.setBlockBreakingProgress(progress);
             }

src/main/java/carpet/script/value/ListValue.java

@@ -380,7 +380,7 @@ public class ListValue extends AbstractListValue implements ContainerValueInterf
 
     private boolean put(Value ind, Value value, boolean replace, boolean extend)
     {
-        if (ind == Value.NULL)
+        if (ind.isNull())
         {
             if (extend && value instanceof AbstractListValue)
             {
@@ -390,7 +390,6 @@ public class ListValue extends AbstractListValue implements ContainerValueInterf
             {
                 items.add(value);
             }
-            return true;
         }
         else
         {
@@ -420,8 +419,8 @@ public class ListValue extends AbstractListValue implements ContainerValueInterf
                 return true;
             }
             items.add(index, value);
-            return true;
         }
+        return true;
     }
 
     @Override

src/main/java/carpet/script/value/ValueConversions.java

@@ -97,7 +97,7 @@ public class ValueConversions
     public static Value fromTimedMemory(Entity e, long expiry, Object v)
     {
         Value ret = fromEntityMemory(e, v);
-        if (ret == Value.NULL || expiry == Long.MAX_VALUE) return ret;
+        if (ret.isNull() || expiry == Long.MAX_VALUE) return ret;
         return ListValue.of(ret, new NumericValue(expiry));
     }