diff --git a/src/com/annimon/ownlang/parser/ast/BinaryExpression.java b/src/com/annimon/ownlang/parser/ast/BinaryExpression.java
index 085d518..1266f02 100644
--- a/src/com/annimon/ownlang/parser/ast/BinaryExpression.java
+++ b/src/com/annimon/ownlang/parser/ast/BinaryExpression.java
@@ -88,13 +88,13 @@ public final class BinaryExpression implements Expression {
     private Value add(Value value1, Value value2) {
         switch (value1.type()) {
             case Types.NUMBER: return add((NumberValue) value1, value2);
-            case Types.STRING: return new StringValue(value1.asString() + value2.asString());
             case Types.ARRAY: return ArrayValue.add((ArrayValue) value1, value2);
             case Types.MAP:
                 if (value2.type() != Types.MAP)
                     throw new TypeException("Cannot merge non map value to map");
                 return MapValue.merge((MapValue) value1, (MapValue) value2);
             case Types.FUNCTION: /* TODO: combining functions */
+            case Types.STRING:
             default:
                 // Concatenation strings
                 return new StringValue(value1.asString() + value2.asString());
diff --git a/src/com/annimon/ownlang/parser/ast/ContainerAccessExpression.java b/src/com/annimon/ownlang/parser/ast/ContainerAccessExpression.java
index 0f06adf..5b13cb1 100644
--- a/src/com/annimon/ownlang/parser/ast/ContainerAccessExpression.java
+++ b/src/com/annimon/ownlang/parser/ast/ContainerAccessExpression.java
@@ -89,13 +89,6 @@ public final class ContainerAccessExpression implements Expression, Accessible {
         return indices.get(index).eval();
     }
     
-    private ArrayValue consumeArray(Value value) {
-        if (value.type() != Types.ARRAY) {
-            throw new TypeException("Array expected");
-        }
-        return (ArrayValue) value;
-    }
-    
     public MapValue consumeMap(Value value) {
         if (value.type() != Types.MAP) {
             throw new TypeException("Map expected");
diff --git a/src/com/annimon/ownlang/parser/ast/MapExpression.java b/src/com/annimon/ownlang/parser/ast/MapExpression.java
index 95e7785..0442866 100644
--- a/src/com/annimon/ownlang/parser/ast/MapExpression.java
+++ b/src/com/annimon/ownlang/parser/ast/MapExpression.java
@@ -20,8 +20,8 @@ public final class MapExpression implements Expression {
     public Value eval() {
         final int size = elements.size();
         final MapValue map = new MapValue(size);
-        for (Expression key : elements.keySet()) {
-            map.set(key.eval(), elements.get(key).eval());
+        for (Map.Entry<Expression, Expression> entry : elements.entrySet()) {
+            map.set(entry.getKey().eval(), entry.getValue().eval());
         }
         return map;
     }