Strange “->* []” expression in C++ source code of cpp.react library

Question

Here is a C++ snippet that I found in the documentation of the cpp.react library:

auto in = D::MakeVar(0);
auto op1 = in ->* [] (int in)
{
    int result = in         


        

Answer 1

@Praetorian's answer is correct. This is code from cpp.react

///////////////////////////////////////////////////////////////////////////////////////////////////
/// operator->* overload to connect inputs to a function and return the resulting node.
///////////////////////////////////////////////////////////////////////////////////////////////////
// Single input
template
<
    typename D,
    typename F,
    template  class TSignal,
    typename TValue,
    class = std::enable_if<
        IsSignal>::value>::type
>
auto operator->*(const TSignal& inputNode, F&& func)
    -> Signal::type>
{
    return D::MakeSignal(std::forward(func), inputNode);
}

// Multiple inputs
template
<
    typename D,
    typename F,
    typename ... TSignals
>
auto operator->*(const InputPack& inputPack, F&& func)
    -> Signal::type>
{
    return apply(
        REACT_IMPL::ApplyHelper::MakeSignal,
        std::tuple_cat(std::forward_as_tuple(std::forward(func)), inputPack.Data));
}

---

///////////////////////////////////////////////////////////////////////////////////////////////////
/// Comma operator overload to create input pack from 2 signals.
///////////////////////////////////////////////////////////////////////////////////////////////////
template
<
    typename D,
    typename TLeftVal,
    typename TRightVal
>
auto operator,(const Signal& a, const Signal& b)
    -> InputPack
{
    return InputPack(a, b);
}

///////////////////////////////////////////////////////////////////////////////////////////////////
/// Comma operator overload to append node to existing input pack.
///////////////////////////////////////////////////////////////////////////////////////////////////
template
<
    typename D,
    typename ... TCurValues,
    typename TAppendValue
>
auto operator,(const InputPack& cur, const Signal& append)
    -> InputPack
{
    return InputPack(cur, append);
}

as you can see it overloaded free function operator->* which takes a signal (D::MakeVar(0)) and a functor (lambda)

and free function operator, which takes two signal