Template Function wrench::unrolled_for

Function Documentation

template<size_t Amount, typename Functor, typename... Args> constexpr auto wrench::unrolled_for (Functor &&functor, Args &&... args) noexcept -> void

Applies the functor Amount times and passes the index of the unrolling as the first argument to the functor. The unrolling is performed at compile time, so the number of iterations should not be too large. The index parameter has a compile-time value, and can therefore be used in constexpr contexts, and can be converted to size_t as a constexpr expression. For example:

auto tuple = std::make_tuple("string", 4, AType*());
unrolled_for<2>([&tuple] (auto i) {
  do_something(get<i>(tuple), get<i + 1>(tuple));
});

Which effectively will become:

do_something(get<0>(tuple), get<1>(tuple));
do_something(get<1>(tuple), get<2>(tuple));

Note

This will cause code bloat if used often. Use this only in cases where compile time unrolling is required with a compile time index variable.

Note

The functor must not return any value.

Parameters

  • functor: The functor to unroll.

  • args: The arguments to the functor.

Template Parameters

  • Amount: The amount of unrolling to do.

  • Functor: The type of the functor.

  • Args: The type of the functor arguments.