Add 'tomlplusplus/' from commit '1c8b7466e4946fcc3bf20484c0e1d001202cca5a'

git-subtree-dir: tomlplusplus
git-subtree-mainline: b85e90fc3480da0e6a48da73201a0b22488cc650
git-subtree-split: 1c8b7466e4946fcc3bf20484c0e1d001202cca5a

1 files changed, 139 insertions, 0 deletions

diff --git a/tomlplusplus/tests/visit.cpp b/tomlplusplus/tests/visit.cpp
new file mode 100644
index 0000000000..efc3c5f30e
--- /dev/null
+++ b/tomlplusplus/tests/visit.cpp
@@ -0,0 +1,139 @@
+// This file is a part of toml++ and is subject to the the terms of the MIT license.
+// Copyright (c) Mark Gillard <mark.gillard@outlook.com.au>
+// See https://github.com/marzer/tomlplusplus/blob/master/LICENSE for the full license text.
+// SPDX-License-Identifier: MIT
+
+#include "tests.hpp"
+TOML_DISABLE_SPAM_WARNINGS;
+
+TEST_CASE("node::visit")
+{
+	value<int64_t> val{ 3 };
+
+	// check lvalue propagates correctly
+	static_cast<node&>(val).visit(
+		[](auto&& v) noexcept
+		{
+			using val_ref_type = decltype(v);
+			static_assert(std::is_lvalue_reference_v<val_ref_type>);
+
+			using val_type = std::remove_reference_t<val_ref_type>;
+			static_assert(!std::is_const_v<val_type>);
+			static_assert(!std::is_volatile_v<val_type>);
+		});
+
+	// check rvalue propagates correctly
+	static_cast<node&&>(val).visit(
+		[](auto&& v) noexcept
+		{
+			using val_ref_type = decltype(v);
+			static_assert(std::is_rvalue_reference_v<val_ref_type>);
+
+			using val_type = std::remove_reference_t<val_ref_type>;
+			static_assert(!std::is_const_v<val_type>);
+			static_assert(!std::is_volatile_v<val_type>);
+		});
+
+	// check const lvalue propagates correctly
+	static_cast<const node&>(val).visit(
+		[](auto&& v) noexcept
+		{
+			using val_ref_type = decltype(v);
+			static_assert(std::is_lvalue_reference_v<val_ref_type>);
+
+			using val_type = std::remove_reference_t<val_ref_type>;
+			static_assert(std::is_const_v<val_type>);
+			static_assert(!std::is_volatile_v<val_type>);
+		});
+
+	// check const rvalue propagates correctly
+	static_cast<const node&&>(val).visit(
+		[](auto&& v) noexcept
+		{
+			using val_ref_type = decltype(v);
+			static_assert(std::is_rvalue_reference_v<val_ref_type>);
+
+			using val_type = std::remove_reference_t<val_ref_type>;
+			static_assert(std::is_const_v<val_type>);
+			static_assert(!std::is_volatile_v<val_type>);
+		});
+
+	// check noexcept
+	static constexpr auto throwing_visitor	   = [](auto&&) noexcept(false) {};
+	static constexpr auto non_throwing_visitor = [](auto&&) noexcept(true) {};
+	static_assert(!noexcept(static_cast<node&>(val).visit(throwing_visitor)));
+	static_assert(!noexcept(static_cast<node&&>(val).visit(throwing_visitor)));
+	static_assert(!noexcept(static_cast<const node&>(val).visit(throwing_visitor)));
+	static_assert(!noexcept(static_cast<const node&&>(val).visit(throwing_visitor)));
+	static_assert(noexcept(static_cast<node&>(val).visit(non_throwing_visitor)));
+	static_assert(noexcept(static_cast<node&&>(val).visit(non_throwing_visitor)));
+	static_assert(noexcept(static_cast<const node&>(val).visit(non_throwing_visitor)));
+	static_assert(noexcept(static_cast<const node&&>(val).visit(non_throwing_visitor)));
+
+	// check return
+	static constexpr auto returns_boolean = [](auto& v) noexcept { return toml::is_integer<decltype(v)>; };
+	auto return_test					  = static_cast<node&>(val).visit(returns_boolean);
+	static_assert(std::is_same_v<decltype(return_test), bool>);
+	CHECK(return_test == true);
+}
+
+TEST_CASE("node_view::visit")
+{
+	value<int64_t> val{ 3 };
+
+	auto view  = node_view{ val };
+	auto cview = node_view{ std::as_const(val) };
+	static_assert(!std::is_same_v<decltype(view), decltype(cview)>);
+
+	// check mutable views propagate correctly
+	view.visit(
+		[](auto&& v) noexcept
+		{
+			using val_ref_type = decltype(v);
+			static_assert(std::is_lvalue_reference_v<val_ref_type>);
+
+			using val_type = std::remove_reference_t<val_ref_type>;
+			static_assert(!std::is_const_v<val_type>);
+			static_assert(!std::is_volatile_v<val_type>);
+		});
+
+	// check const views propagate correctly
+	cview.visit(
+		[](auto&& v) noexcept
+		{
+			using val_ref_type = decltype(v);
+			static_assert(std::is_lvalue_reference_v<val_ref_type>);
+
+			using val_type = std::remove_reference_t<val_ref_type>;
+			static_assert(std::is_const_v<val_type>);
+			static_assert(!std::is_volatile_v<val_type>);
+		});
+
+	// check noexcept
+	static constexpr auto throwing_visitor	   = [](auto&&) noexcept(false) {};
+	static constexpr auto non_throwing_visitor = [](auto&&) noexcept(true) {};
+	static_assert(!noexcept(view.visit(throwing_visitor)));
+	static_assert(!noexcept(cview.visit(throwing_visitor)));
+	static_assert(noexcept(view.visit(non_throwing_visitor)));
+	static_assert(noexcept(cview.visit(non_throwing_visitor)));
+
+	// check return
+	static constexpr auto returns_boolean = [](auto&& v) noexcept { return toml::is_integer<decltype(v)>; };
+	auto return_test					  = view.visit(returns_boolean);
+	static_assert(std::is_same_v<decltype(return_test), bool>);
+	CHECK(return_test == true);
+
+	// check that null views don't invoke the visitor
+	// clang-format off
+	auto null_view	= decltype(view){};
+	auto null_cview = decltype(cview){};
+	unsigned count{};
+	unsigned mask{};
+	view.visit([&](auto&&)       noexcept { count++; mask |= 0b0001u; });
+	cview.visit([&](auto&&)      noexcept { count++; mask |= 0b0010u; });
+	null_view.visit([&](auto&&)  noexcept { count++; mask |= 0b0100u; });
+	null_cview.visit([&](auto&&) noexcept { count++; mask |= 0b1000u; });
+	CHECK(count == 2u);
+	CHECK(mask == 0b0011u);
+	// clang-format on
+}