cpp-lazy-stream/include/stream/view/join.h

#pragma once

#include <iterator/join_iterator.h>

#define FWD(x) std::forward<decltype(x)>(x)

namespace stream::ranges {
template <typename S> struct join_view {
private:
  S stream_;

public:
  join_view(S && stream) : stream_(FWD(stream)) {}

  auto begin() const { return iterator::joining_iterator(stream_); }
  auto end() const { return iterator::sentinel; }
};

template <typename S> join_view(S &&) -> join_view<S>;
}

namespace stream::ranges::views {
struct join {
  template <typename Stream> friend auto operator|(Stream && stream, join) {
    return join_view(FWD(stream));
  }
};
}

#undef FWD