added const access for operator[] (issue #7)

include/array.h

@@ -110,7 +110,7 @@ public:
      *  @param  index   field index
      *  @return Field
      */
-    const Field &get(uint8_t index);
+    const Field &get(uint8_t index) const;
 
     /**
      *  Get number of elements on this array
@@ -142,6 +142,16 @@ public:
         return ArrayFieldProxy(this, index);
     }
     
+    /**
+     *  Get a const field
+     *  @param  index   field index
+     *  @return Field
+     */
+    const Field &operator[](uint8_t index) const
+    {
+        return get(index);
+    }
+
     /**
      *  Write encoded payload to the given buffer.
      *  @param  buffer

include/table.h

@@ -122,6 +122,16 @@ public:
         return AssociativeFieldProxy(this, name);
     }
 
+    /**
+     *  Get a const field
+     *
+     *  @param  name    field name
+     */
+    const Field &operator[](const std::string& name) const
+    {
+        return get(name);
+    }
+
     /**
      *  Write encoded payload to the given buffer. 
      *  @param  buffer

src/array.cpp

@@ -58,7 +58,7 @@ Array::Array(const Array &array)
  *  @param  index   field index
  *  @return Field
  */
-const Field &Array::get(uint8_t index)
+const Field &Array::get(uint8_t index) const
 {
     // used if index does not exist
     static ShortString empty;