Familiar template syntax for generic lambdas

Question

For c++20 it is proposed to add the following syntax for generic lambdas p0428r2.pdf

auto f = [](          


        

Answer 1

The result of a lambda expression is not a function; it is a function object. That is, it is a class type that has an operator() overload on it. So this:

auto f = []<typename T>( T t ) {};

Is equivalent to this:

struct unnamed
{
  template<typename T>
  void operator()(T t) {}
};

auto f = unnamed{};

If you want to explicitly provide template arguments to a lambda function, you have to call operator() explicitly: f.operator()<template arguments>(parameters);.