e 
creation of the lambda function and remains constant during the lifetime 
of the lambda function object.
For example:
</p>
<pre class="programlisting">
int i = 1;
(_1 = 2, _1 + i)(i);
</pre>
<p>
The comma operator is overloaded to combine lambda expressions into a sequence;
the resulting unary lambda functor first assigns 2 to its argument, 
then adds the value of <code class="literal">i</code> to it.
The value of the expression in the last line is 3, not 4. 
In other words, the lambda expression that is