Function TEST

cpp/src/arrow/compute/kernels/scalar_cast_test.cc:163–245

}

TEST(Cast, CanCast) {
  auto ExpectCanCast = [](std::shared_ptr<DataType> from,
                          std::vector<std::shared_ptr<DataType>> to_set,
                          bool expected = true) {
    for (auto to : to_set) {
      EXPECT_EQ(CanCast(*from, *to), expected) << "  from: " << from->ToString() << "\n"
                                               << "    to: " << to->ToString();
    }
  };

  auto ExpectCannotCast = [ExpectCanCast](std::shared_ptr<DataType> from,
                                          std::vector<std::shared_ptr<DataType>> to_set) {
    ExpectCanCast(from, to_set, /*expected=*/false);
  };

  ExpectCanCast(null(), {boolean()});
  ExpectCanCast(null(), kNumericTypes);
  ExpectCanCast(null(), kBaseBinaryAndViewTypes);
  ExpectCanCast(
      null(), {date32(), date64(), time32(TimeUnit::MILLI), timestamp(TimeUnit::SECOND)});
  ExpectCanCast(dictionary(uint16(), null()), {null()});

  ExpectCanCast(boolean(), {boolean()});
  ExpectCanCast(boolean(), kNumericTypes);
  ExpectCanCast(boolean(), {utf8(), utf8_view(), large_utf8()});
  ExpectCanCast(dictionary(int32(), boolean()), {boolean()});

  ExpectCannotCast(boolean(), {null()});
  ExpectCannotCast(boolean(), {binary(), large_binary()});
  ExpectCannotCast(boolean(), {date32(), date64(), time32(TimeUnit::MILLI),
                               timestamp(TimeUnit::SECOND)});

  for (auto from_numeric : kNumericTypes) {
    ExpectCanCast(from_numeric, {boolean()});
    ExpectCanCast(from_numeric, kNumericTypes);
    ExpectCanCast(from_numeric, {utf8(), large_utf8()});
    ExpectCanCast(dictionary(int32(), from_numeric), {from_numeric});

    ExpectCannotCast(from_numeric, {null()});
  }

  for (auto from_base_binary : kBaseBinaryAndViewTypes) {
    ExpectCanCast(from_base_binary, {boolean()});
    ExpectCanCast(from_base_binary, kNumericTypes);
    ExpectCanCast(from_base_binary, kBaseBinaryTypes);
    // TODO(GH-43010): include is_binary_view_like() types here once array_take
    // can handle string-views
    if (!is_binary_view_like(*from_base_binary)) {
      ExpectCanCast(dictionary(int64(), from_base_binary), {from_base_binary});
    }

    // any cast which is valid for the dictionary is valid for the DictionaryArray
    ExpectCanCast(dictionary(uint32(), from_base_binary), kBaseBinaryTypes);
    ExpectCanCast(dictionary(int16(), from_base_binary), kNumericTypes);

    ExpectCannotCast(from_base_binary, {null()});
  }