hash code and stump of map

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

@@ -13,6 +13,7 @@ import net.minecraft.item.ItemPlacementContext;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.GlobalPos;
 import net.minecraft.util.Hand;
 import net.minecraft.util.hit.BlockHitResult;
 import net.minecraft.util.math.BlockPos;
@@ -254,6 +255,14 @@ public class BlockValue extends Value
         return new BlockValue(blockState, world, pos);
     }
 
+    @Override
+    public int hashCode()
+    {
+        if (world != null && pos != null )
+            return GlobalPos.create(world.getDimension().getType(), pos).hashCode();
+        return ("b"+getString()).hashCode();
+    }
+
     public BlockPos getPos()
     {
         return pos;

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

@@ -138,6 +138,13 @@ public class EntityValue extends Value
         return "entity";
     }
 
+
+    @Override
+    public int hashCode()
+    {
+        return entity.hashCode();
+    }
+
     public static Pair<EntityType<?>, Predicate<? super Entity>> getPredicate(String who)
     {
         Pair<EntityType<?>, Predicate<? super Entity>> res = entityPredicates.get(who);

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

@@ -43,5 +43,11 @@ public class FunctionSignatureValue extends Value
     }
     public List<String> getGlobals() {return globals;}
 
+    @Override
+    public int hashCode()
+    {
+        throw new UnsupportedOperationException("function signature value cannot be used as map key");
+    }
+
 
 }

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

@@ -19,4 +19,10 @@ public class GlobalValue extends Value
     {
         return false;
     }
+
+    @Override
+    public int hashCode()
+    {
+        throw new UnsupportedOperationException("global value cannot be used as map key");
+    }
 }

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

@@ -44,6 +44,12 @@ public abstract class LazyListValue extends AbstractListValue implements Iterato
             {
                 return stepp > 0?(current < limit):(current > limit);
             }
+
+            @Override
+            public String getString()
+            {
+                return String.format("[%d, %d, ..., %d]",start, start+stepp, limit);
+            }
         };
     }
 
@@ -145,4 +151,10 @@ public abstract class LazyListValue extends AbstractListValue implements Iterato
         ((LazyListValue)copy).reset();
         return copy;
     }
+
+    @Override
+    public int hashCode()
+    {
+        return ("i"+getString()).hashCode();
+    }
 }

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

@@ -4,11 +4,7 @@ import carpet.script.exception.InternalExpressionException;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.registry.Registry;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Iterator;
-import java.util.List;
+import java.util.*;
 import java.util.stream.Collectors;
 
 import static java.lang.Math.abs;
@@ -322,9 +318,16 @@ public class ListValue extends AbstractListValue
         index = index % numitems;
         return items.get((int)index);
     }
+
     @Override
     public String getTypeString()
     {
         return "list";
     }
+
+    @Override
+    public int hashCode()
+    {
+        return items.hashCode();
+    }
 }

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

@@ -0,0 +1,34 @@
+package carpet.script.value;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+public class MapValue extends AbstractListValue
+{
+    private Map<Value, Value> map;
+    public MapValue()
+    {
+        map = new HashMap<>();
+    }
+
+    @Override
+    public Iterator<Value> iterator()
+    {
+        return map.keySet().iterator();
+    }
+
+    @Override
+    public String getString()
+    {
+        return Arrays.toString(map.entrySet().toArray());
+    }
+
+    @Override
+    public boolean getBoolean()
+    {
+        return !map.isEmpty();
+    }
+
+}

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

@@ -44,4 +44,10 @@ public class NullValue extends NumericValue // TODO check nonsingleton code
     {
         return "null";
     }
+
+    @Override
+    public int hashCode()
+    {
+        return 0;
+    }
 }

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

@@ -179,4 +179,13 @@ public class NumericValue extends Value
         return "number";
     }
 
+    @Override
+    public int hashCode()
+    {
+        if (Math.abs(Math.floor(value + 0.5D)-value) < epsilon) // is sufficiently close to the integer value
+            return Long.hashCode(getLong());
+        return Double.hashCode(value);
+    }
+
+
 }

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

@@ -182,4 +182,12 @@ public abstract class Value implements Comparable<Value>, Cloneable
     {
         throw new InternalExpressionException("How did you get here? Cannot get type of an intenal type.");
     }
+
+    @Override
+    public int hashCode()
+    {
+        String stringVal = getString();
+        if (stringVal.isEmpty()) return 0;
+        return ("s"+stringVal).hashCode();
+    }
 }