[Boost-users] [mpl] nested lambdas?

Suppose I'm tying to build a nested lambda expression, like so (typename...::type omitted for simplicity): lambda<higher_order_func<lambda<foo<_1> >, _2> > - Is this legal? - Does the _1 refer to the first argument of the inner lambda, or of the outer lambda? - Can the above be overridden? I.e. what if I want to refer to the arguments of both lambdas within the inner lambda?