make optional constexpr in C++14

2026-07-05 16:10:48 +02:00 · 2026-02-07 02:12:24 +01:00
parent bfdf0c73f9
commit 3df23370e6
28 changed files with 1405 additions and 544 deletions
@@ -0,0 +1,96 @@
+// Copyright (C) 2026, Andrzej Krzemieński.
+//
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+
+#include "boost/optional.hpp"
+
+#ifdef BOOST_OPTIONAL_USES_CONSTEXPR_IMPLEMENTATION
+
+struct Record
+{
+  int i;
+  constexpr explicit Record(int i) : i(i) {}
+  constexpr int operator()() const { return i; }
+};
+
+namespace test_int
+{
+  constexpr boost::optional<int> oN;
+  static_assert(!oN);
+  static_assert(oN == boost::none);
+  static_assert(oN <= boost::none);
+  static_assert(!(oN != boost::none));
+  static_assert(oN == oN);
+  static_assert(!oN.has_value());
+  static_assert(oN.value_or({}) == 0);
+  static_assert(oN.value_or(0) == 0);
+  static_assert(oN.value_or_eval(Record(9)) == 9);
+  constexpr boost::optional<int> oNc = oN;
+  constexpr boost::optional<int> oNd = boost::none;
+  constexpr boost::optional<int> oNe = {};
+  static_assert(oNc == oN);
+  static_assert(oNd == oN);
+  static_assert(oNe == oN);
+
+  constexpr boost::optional<int> o1 = 1;
+  constexpr boost::optional<int> o2 {2};
+
+  static_assert(o1);
+  static_assert(o1.has_value());
+  static_assert(o1 != boost::none);
+  static_assert(o1 != oN);
+  static_assert(o1 > oN);
+  static_assert(o1 >= oN);
+  static_assert(*o1 == 1);
+  static_assert(o1.value() == 1);
+  static_assert(o1.value_or(0) == 1);
+  static_assert(o1.value_or({}) == 1);
+  static_assert(o1.value_or_eval(Record(9)) == 1);
+  static_assert(o1 == 1);
+  static_assert(o2);
+  static_assert(o2 != o1);
+  static_assert(o2 > o1);
+
+  constexpr bool test_reset() {
+    boost::optional<int> o = 1;
+    assert(o);
+    o = boost::none;
+    assert(!o);
+    return o == boost::none;
+  }
+
+  static_assert(test_reset());
+}
+
+namespace test_record
+{
+  constexpr boost::optional<Record> rN = boost::none;
+  constexpr boost::optional<Record> r1 = Record(1);
+  constexpr boost::optional<Record> r2 (boost::in_place_init, 2);
+
+  static_assert(!rN);
+  static_assert(rN == boost::none);
+  static_assert(r1);
+  static_assert(r1 != boost::none);
+  static_assert(r2);
+  static_assert(rN.value_or(Record(9)).i == 9);
+  static_assert(r1->i == 1);
+  static_assert(r2.value().i == 2);
+}
+
+namespace test_optional_ref
+{
+  constexpr int gi = 9;
+  constexpr boost::optional<const int&> iref = gi;
+  static_assert(iref);
+  static_assert(*iref == 9);
+}
+
+#endif // BOOST_OPTIONAL_USES_CONSTEXPR_IMPLEMENTATION