added copy and fixed cleaning of semicolons

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

@@ -58,6 +58,7 @@ import java.util.stream.Collectors;
 
 import static carpet.script.value.NBTSerializableValue.nameFromRegistryId;
 
+// TODO: decide whether copy(entity) should duplicate entity in the world.
 public class EntityValue extends Value
 {
     private Entity entity;

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

@@ -43,6 +43,15 @@ public class ListValue extends AbstractListValue implements ContainerValueInterf
     {
         return new ListValue(items);
     }
+
+    @Override
+    public Value deepcopy()
+    {
+        List<Value> copyItems = new ArrayList<>(items.size());
+        for (Value entry: items) copyItems.add(entry.deepcopy());
+        return new ListValue(copyItems);
+    }
+
     public ListValue(Collection<? extends Value> list)
     {
         items = new ArrayList<>();

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

@@ -63,6 +63,15 @@ public class MapValue extends AbstractListValue implements ContainerValueInterfa
     {
         return new MapValue(map);
     }
+
+    @Override
+    public Value deepcopy()
+    {
+        Map<Value, Value> copyMap = new HashMap<>();
+        map.forEach((key, value) -> copyMap.put(key.deepcopy(), value.deepcopy()));
+        return new MapValue(copyMap);
+    }
+
     public MapValue(Map<Value,Value> other)
     {
         map = new HashMap<>(other);

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

@@ -95,11 +95,26 @@ public class NBTSerializableValue extends Value implements ContainerValueInterfa
         return value;
     }
 
+
+    @Override
     public Value clone()
     {
-        return new NBTSerializableValue(getTag().copy());
+        // sets only nbttag, even if emtpy;
+        NBTSerializableValue copy = new NBTSerializableValue(nbtTag);
+        copy.nbtSupplier = this.nbtSupplier;
+        copy.nbtString = this.nbtString;
+        return copy;
     }
 
+    @Override
+    public Value deepcopy()
+    {
+        NBTSerializableValue copy = (NBTSerializableValue) clone();
+        // same fields except when tag is set - need to copy it.
+        if (copy.nbtTag != null)
+            copy.nbtTag = copy.getTag().copy();
+        return copy;
+    }
 
     public static InventoryLocator locateInventory(CarpetContext c, List<LazyValue> params, int offset)
     {

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

@@ -189,4 +189,17 @@ public abstract class Value implements Comparable<Value>, Cloneable
         if (stringVal.isEmpty()) return 0;
         return ("s"+stringVal).hashCode();
     }
+
+    public Value deepcopy()
+    {
+        try
+        {
+            return (Value)this.clone();
+        }
+        catch (CloneNotSupportedException e)
+        {
+            // should never happen
+            throw new InternalExpressionException("Cannot make a copy of value: "+this);
+        }
+    };
 }