lgr_reduce.hpp

#pragma once

#include <lgr_functional.hpp>

namespace lgr {

template <class Range, class T, class BinaryOp, class UnaryOp>
T
transform_reduce(Range const& range, T init, BinaryOp binary_op, UnaryOp unary_op)
{
  auto       first = range.begin();
  auto const last  = range.end();
  for (; first != last; ++first) {
    init = binary_op(std::move(init), unary_op(*first));
  }
  return init;
}

template <class Range, class T>
T
reduce(Range const& range, T init)
{
  using input_value_type = typename Range::value_type;
  auto const unop        = [](input_value_type const i) { return T(i); };
  return transform_reduce(range, init, plus<T>(), unop);
}

template <class Range, class UnaryPredicate>
bool
any_of(Range const& range, UnaryPredicate p)
{
  return transform_reduce(range, false, logical_or(), p);
}

template <class Range, class UnaryPredicate>
bool
all_of(Range const& range, UnaryPredicate p)
{
  return transform_reduce(range, true, logical_and(), p);
}

template <class Range>
bool
all_of(Range const& range)
{
  return all_of(range, identity<bool>());
}

template <class Range>
bool
any_of(Range const& range)
{
  return any_of(range, identity<bool>());
}

}  // namespace lgr