. operator as lvalue

src/main/java/carpet/script/Context.java

@@ -16,6 +16,7 @@ public class Context
     static final int ITERATOR = 6;
     static final int SIGNATURE = 7;
     static final int LOCALIZATION = 8;
+    static final int LVALUE = 9;
 
     private Map<String, LazyValue> variables = new HashMap<>();
 

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

@@ -16,6 +16,7 @@ import carpet.script.value.AbstractListValue;
 import carpet.script.value.ContainerValueInterface;
 import carpet.script.value.FunctionSignatureValue;
 import carpet.script.value.GlobalValue;
+import carpet.script.value.LContainerValue;
 import carpet.script.value.LazyListValue;
 import carpet.script.value.ListValue;
 import carpet.script.value.MapValue;
@@ -1242,11 +1243,18 @@ public class Expression implements Cloneable
      */
     public void Operators()
     {
-        addBinaryOperator(".", precedence.get("attribute~."),true, (container, key) ->
+        addLazyBinaryOperator(".", precedence.get("attribute~."),true, (c, t, container_lv, key_lv) ->
         {
-            if (container instanceof ContainerValueInterface)
+            Value container = container_lv.evalValue(c);
-                return ((ContainerValueInterface) container).get(key);
+            if (!(container instanceof ContainerValueInterface))
-            throw new InternalExpressionException("Cannot access elements of a non-container");
+                throw new InternalExpressionException("Cannot access elements of a non-container");
+            Value address = key_lv.evalValue(c);
+            if (t != Context.LVALUE)
+            {
+                Value retVal = ((ContainerValueInterface) container).get(address);
+                return (cc, ct) -> retVal;
+            }
+            return (cc, ct) -> new LContainerValue((ContainerValueInterface) container, address);
         });
         addBinaryOperator("+", precedence.get("addition+-"), true, Value::add);
         addBinaryOperator("-", precedence.get("addition+-"), true, Value::subtract);
@@ -1290,7 +1298,7 @@ public class Expression implements Cloneable
 
         addLazyBinaryOperator("=", precedence.get("assign=<>"), false, (c, t, lv1, lv2) ->
         {
-            Value v1 = lv1.evalValue(c);
+            Value v1 = lv1.evalValue(c, Context.LVALUE);
             Value v2 = lv2.evalValue(c);
             if (v1 instanceof ListValue.ListConstructorValue && v2 instanceof ListValue)
             {
@@ -1309,6 +1317,11 @@ public class Expression implements Cloneable
                 }
                 return (cc, tt) -> Value.TRUE;
             }
+            if (v1 instanceof LContainerValue)
+            {
+                Value ret = ((LContainerValue) v1).getContainer().put(((LContainerValue) v1).getAddress(), v2);
+                return (cc, tt) -> ret;
+            }
             v1.assertAssignable();
             String varname = v1.getVariable();
             Value copy = v2.reboundedTo(varname);

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

@@ -0,0 +1,30 @@
+package carpet.script.value;
+
+import carpet.script.exception.ExpressionException;
+
+public abstract class FrameworkValue extends Value
+{
+    @Override
+    public String getString()
+    {
+        throw new ExpressionException("Scarpet language component cannot be used");
+    }
+
+    @Override
+    public boolean getBoolean()
+    {
+        throw new ExpressionException("Scarpet language component cannot be used");
+    }
+
+    @Override
+    public Value clone()
+    {
+        throw new ExpressionException("Scarpet language component cannot be used");
+    }
+
+    @Override
+    public int hashCode()
+    {
+        throw new UnsupportedOperationException("Scarpet language component cannot be used as map key");
+    }
+}

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

@@ -4,29 +4,13 @@ import carpet.script.exception.ExpressionException;
 
 import java.util.List;
 
-public class FunctionSignatureValue extends Value
+public class FunctionSignatureValue extends FrameworkValue
 {
     private String identifier;
     private List<String> arguments;
     private List<String> globals;
 
-    @Override
-    public String getString()
-    {
-        throw new ExpressionException("Function "+identifier+" is not defined yet");
-    }
 
-    @Override
-    public boolean getBoolean()
-    {
-        throw new ExpressionException("Function "+identifier+" is not defined yet");
-    }
-
-    @Override
-    public Value clone()
-    {
-        throw new ExpressionException("Function "+identifier+" is not defined yet");
-    }
     public FunctionSignatureValue(String name, List<String> args, List<String> globals)
     {
         this.identifier = name;
@@ -43,11 +27,7 @@ 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/LContainerValue.java

@@ -0,0 +1,16 @@
+package carpet.script.value;
+
+public class LContainerValue extends FrameworkValue
+{
+    private ContainerValueInterface container;
+    private Value address;
+
+    public LContainerValue(ContainerValueInterface c, Value v)
+    {
+        container = c;
+        address = v;
+    }
+
+    public ContainerValueInterface getContainer() {return container; }
+    public Value getAddress() {return address; }
+}