added copy and fixed cleaning of semicolons

src/main/java/carpet/script/Expression.java

@@ -46,7 +46,6 @@ import java.util.function.Supplier;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
-import java.util.stream.StreamSupport;
 
 import static java.lang.Math.abs;
 import static java.lang.Math.max;
@@ -2775,6 +2774,8 @@ public class Expression implements Cloneable
     {
         addUnaryFunction("hash_code", v -> new NumericValue(v.hashCode()));
 
+        addUnaryFunction("copy", Value::deepcopy);
+
         addLazyFunction("bool", 1, (c, t, lv) -> {
             Value v = lv.get(0).evalValue(c, Context.BOOLEAN);
             if (v instanceof StringValue)
@@ -3044,21 +3045,7 @@ public class Expression implements Cloneable
 
         Tokenizer tokenizer = new Tokenizer(this, expression, allowComments, allowNewlineSubstitutions);
         // stripping lousy but acceptable semicolons
-        Iterable<Tokenizer.Token> iterable = () -> tokenizer;
-        List<Tokenizer.Token> originalTokens = StreamSupport.stream(iterable.spliterator(), false).collect(Collectors.toList());
-        List<Tokenizer.Token> cleanedTokens = new ArrayList<>();
-        Tokenizer.Token last = null;
-        while (originalTokens.size() > 0)
-        {
-            Tokenizer.Token current = originalTokens.remove(originalTokens.size()-1);
-            if (current.type != Tokenizer.Token.TokenType.OPERATOR
-                    || !current.surface.equals(";")
-                    || (last != null && last.type != Tokenizer.Token.TokenType.CLOSE_PAREN && last.type != Tokenizer.Token.TokenType.COMMA && !last.surface.equals(";")))
-                cleanedTokens.add(current);
-            if (current.type != Tokenizer.Token.TokenType.MARKER)
-                last = current;
-        }
-        Collections.reverse(cleanedTokens);
+        List<Tokenizer.Token> cleanedTokens = tokenizer.fixSemicolons();
 
         Tokenizer.Token lastFunction = null;
         Tokenizer.Token previousToken = null;

src/main/java/carpet/script/Tokenizer.java

@@ -4,8 +4,11 @@ import carpet.script.exception.ExpressionException;
 import carpet.script.exception.InternalExpressionException;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
 
 /**
  * Expression tokenizer that allows to iterate over a {@link String}
@@ -38,6 +41,32 @@ public class Tokenizer implements Iterator<Tokenizer.Token>
         this.newLinesMarkers = allowNewLineMakers;
     }
 
+    public List<Token> fixSemicolons()
+    {
+        Iterable<Token> iterable = () -> this;
+        List<Token> originalTokens = StreamSupport.stream(iterable.spliterator(), false).collect(Collectors.toList());
+        List<Token> cleanedTokens = new ArrayList<>();
+        Token last = null;
+        while (originalTokens.size() > 0)
+        {
+            Token current = originalTokens.remove(originalTokens.size()-1);
+            if (!isSemicolon(current)
+                    || (last != null && last.type != Token.TokenType.CLOSE_PAREN && last.type != Token.TokenType.COMMA && !isSemicolon(last)))
+            {
+                if (isSemicolon(current))
+                {
+                    current.surface = ";";
+                    current.type = Token.TokenType.OPERATOR;
+                }
+                cleanedTokens.add(current);
+            }
+            if (current.type != Token.TokenType.MARKER)
+                last = current;
+        }
+        Collections.reverse(cleanedTokens);
+        return cleanedTokens;
+    }
+
     @Override
     public boolean hasNext()
     {
@@ -60,6 +89,12 @@ public class Tokenizer implements Iterator<Tokenizer.Token>
                 || (ch >= 'A' && ch <= 'F');
     }
 
+    public static boolean isSemicolon(Token tok)
+    {
+        return (    tok.type == Token.TokenType.OPERATOR && tok.surface.equals(";") )
+                || (tok.type == Token.TokenType.UNARY_OPERATOR && tok.surface.equals(";u") );
+    }
+
     public static List<Token> simplepass(String input)
     {
         Tokenizer tok = new Tokenizer(null, input, false, false);

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);
+        }
+    };
 }