Change bind overload into or_else

optional.hpp

@@ -113,24 +113,24 @@ using invoke_result_t = typename invoke_result<F, Us...>::type;
 template <class U>
 using fixup_void = conditional_t<std::is_void<U>::value, monostate, U>;
 
-template <class F, class U> struct get_invoke_optional_ret {
+template <class F, class... U> struct get_invoke_optional_ret {
   using type = invoke_result_t<
       conditional_t<std::is_lvalue_reference<F>::value,
                     typename remove_reference_t<F>::value_type &,
                     typename remove_reference_t<F>::value_type &&>,
-      U>;
+      U...>;
 };
 
-template <class F, class U>
+template <class F, class... U>
-using get_invoke_ret =
+using get_invoke_ret = typename conditional_t<is_optional<F>::value,
-    typename conditional_t<is_optional<F>::value, get_invoke_optional_ret<F, U>,
+                                              get_invoke_optional_ret<F, U...>,
-                           invoke_result<F, U>>::type;
+                                              invoke_result<F, U...>>::type;
 
 template <class F, class U>
 using get_map_return = optional<fixup_void<get_invoke_ret<F, U>>>;
 
-template <class F, class U>
+template <class F, class... U>
-using returns_void = std::is_void<get_invoke_ret<F, U>>;
+using returns_void = std::is_void<get_invoke_ret<F, U...>>;
 
 template <class T>
 using disable_if_optional = enable_if_t<!is_optional<T>::value>;
@@ -138,11 +138,11 @@ using disable_if_optional = enable_if_t<!is_optional<T>::value>;
 template <class T>
 using enable_if_optional = enable_if_t<is_optional<T>::value>;
 
-template <class T, class U>
+template <class T, class... U>
-using enable_if_ret_void = enable_if_t<returns_void<T &&, U>::value>;
+using enable_if_ret_void = enable_if_t<returns_void<T &&, U...>::value>;
 
-template <class T, class U>
+template <class T, class... U>
-using disable_if_ret_void = enable_if_t<!returns_void<T &&, U>::value>;
+using disable_if_ret_void = enable_if_t<!returns_void<T &&, U...>::value>;
 }
 
 struct in_place_t {
@@ -766,7 +766,7 @@ public:
   }
 
   template <class F>
-  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T> bind(F &&f) & {
+  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T> and_then(F &&f) & {
     using result = detail::invoke_result_t<F, T>;
     static_assert(detail::is_optional<result>::value,
                   "F must return an optional");
@@ -776,7 +776,7 @@ public:
   }
 
   template <class F>
-  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T> bind(F &&f) && {
+  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T> and_then(F &&f) && {
     using result = detail::invoke_result_t<F, T>;
     static_assert(detail::is_optional<result>::value,
                   "F must return an optional");
@@ -786,7 +786,7 @@ public:
   }
 
   template <class F>
-  constexpr detail::invoke_result_t<F, T> bind(F &&f) const & {
+  constexpr detail::invoke_result_t<F, T> and_then(F &&f) const & {
     using result = detail::invoke_result_t<F, T>;
     static_assert(detail::is_optional<result>::value,
                   "F must return an optional");
@@ -796,7 +796,7 @@ public:
   }
 
   template <class F>
-  constexpr detail::invoke_result_t<F, T> bind(F &&f) const && {
+  constexpr detail::invoke_result_t<F, T> and_then(F &&f) const && {
     using result = detail::invoke_result_t<F, T>;
     static_assert(detail::is_optional<result>::value,
                   "F must return an optional");
@@ -805,69 +805,6 @@ public:
                        : result(nullopt);
   }
 
-  template <class F, class E>
-      detail::invoke_result_t<F, T> bind(F &&f, E &&e) &
-      noexcept(noexcept(detail::invoke(std::forward<F>(f),
-                                       std::declval<T &>())) &&
-               noexcept(std::forward<E>(e)())) {
-    using result = detail::invoke_result_t<F, T>;
-    static_assert(detail::is_optional<result>::value,
-                  "F must return an optional");
-
-    if (!has_value())
-      return result(nullopt);
-
-    auto ret = detail::invoke(std::forward<F>(f), **this);
-    if (!ret)
-      detail::invoke(e);
-    return ret;
-  }
-
-  template <class F, class E>
-  detail::invoke_result_t<F, T> bind(F &&f, E &&e) && {
-    using result = detail::invoke_result_t<F, T>;
-    static_assert(detail::is_optional<result>::value,
-                  "F must return an optional");
-
-    if (!has_value())
-      return result(nullopt);
-
-    auto ret = detail::invoke(std::forward<F>(f), std::move(**this));
-    if (!ret)
-      detail::invoke(e);
-    return ret;
-  }
-
-  template <class F, class E>
-  detail::invoke_result_t<F, T> bind(F &&f, E &&e) const & {
-    using result = detail::invoke_result_t<F, T>;
-    static_assert(detail::is_optional<result>::value,
-                  "F must return an optional");
-
-    if (!has_value())
-      return result(nullopt);
-
-    auto ret = detail::invoke(std::forward<F>(f), **this);
-    if (!ret)
-      detail::invoke(e);
-    return ret;
-  }
-
-  template <class F, class E>
-  detail::invoke_result_t<F, T> bind(F &&f, E &&e) const && {
-    using result = detail::invoke_result_t<F, T>;
-    static_assert(detail::is_optional<result>::value,
-                  "F must return an optional");
-
-    if (!has_value())
-      return result(nullopt);
-
-    auto ret = detail::invoke(std::forward<F>(f), std::move(**this));
-    if (!ret)
-      detail::invoke(e);
-    return ret;
-  }
-
   template <class F, detail::disable_if_optional<F> * = nullptr,
             detail::disable_if_ret_void<F, T &> * = nullptr>
       detail::get_map_return<F, T &> map(F &&f) &
@@ -1019,6 +956,62 @@ public:
     return monostate{};
   }
 
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> constexpr or_else(F &&f) & {
+    if (has_value())
+      return *this;
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> constexpr or_else(F &&f) & {
+    return has_value() ? *this : std::forward<F>(f)();
+  }
+
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) && {
+    if (has_value())
+      return std::move(*this);
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> constexpr or_else(F &&f) && {
+    return has_value() ? std::move(*this) : std::forward<F>(f)();
+  }
+
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const & {
+    if (has_value())
+      return *this;
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> constexpr or_else(F &&f) const & {
+    return has_value() ? *this : std::forward<F>(f)();
+  }
+
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const && {
+    if (has_value())
+      return std::move(*this);
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const && {
+    return has_value() ? std::move(*this) : std::forward<F>(f)();
+  }
+
   template <class F, class U> U map_or(F &&f, U &&u) & {
     return has_value() ? detail::invoke(std::forward<F>(f), **this)
                        : std::forward<U>(u);

tests/monadic.cpp

@@ -10,7 +10,6 @@
 constexpr int get_int(int) { return 42; }
 constexpr tl::optional<int> get_opt_int(int) { return 42; }
 
-
 // What is Clang Format up to?!
 TEST_CASE("Monadic operations",
           "[monadic]"){SECTION("map"){// lhs is empty
@@ -58,7 +57,8 @@ REQUIRE(o6r.value() == 42);
 tl::optional<int> o7 = 40;
 auto f7 = tl::make_optional([](const int &i) { return; });
 auto o7r = o7.map(f7);
-STATIC_REQUIRE((std::is_same<decltype(o7r), tl::optional<tl::monostate>>::value));
+STATIC_REQUIRE(
+    (std::is_same<decltype(o7r), tl::optional<tl::monostate>>::value));
 REQUIRE(o6r.has_value());
 
 // test each overload in turn
@@ -191,7 +191,6 @@ auto o39r = std::move(o39).map(tl::make_optional([](int){return;}));
 REQUIRE(!o39r);
 }
 
-
 SECTION("map constexpr") {
   // test each overload in turn
   constexpr tl::optional<int> o16 = 42;
@@ -228,170 +227,115 @@ constexpr auto o38r = std::move(o38).map(opt_int);
   STATIC_REQUIRE(!o38r);
 }
 
-SECTION("bind") {
+SECTION("and_then") {
 
   // lhs is empty
   tl::optional<int> o1;
-  auto o1r = o1.bind([](int i) { return tl::optional<float>{42}; });
+  auto o1r = o1.and_then([](int i) { return tl::optional<float>{42}; });
   STATIC_REQUIRE((std::is_same<decltype(o1r), tl::optional<float>>::value));
   REQUIRE(!o1r);
 
   // lhs has value
   tl::optional<int> o2 = 12;
-  auto o2r = o2.bind([](int i) { return tl::optional<float>{42}; });
+  auto o2r = o2.and_then([](int i) { return tl::optional<float>{42}; });
   STATIC_REQUIRE((std::is_same<decltype(o2r), tl::optional<float>>::value));
   REQUIRE(o2r.value() == 42.f);
 
   // lhs is empty, rhs returns empty
   tl::optional<int> o3;
-  auto o3r = o3.bind([](int i) { return tl::optional<float>{}; });
+  auto o3r = o3.and_then([](int i) { return tl::optional<float>{}; });
   STATIC_REQUIRE((std::is_same<decltype(o3r), tl::optional<float>>::value));
   REQUIRE(!o3r);
 
   // rhs returns empty
   tl::optional<int> o4 = 12;
-  auto o4r = o4.bind([](int i) { return tl::optional<float>{}; });
+  auto o4r = o4.and_then([](int i) { return tl::optional<float>{}; });
   STATIC_REQUIRE((std::is_same<decltype(o4r), tl::optional<float>>::value));
   REQUIRE(!o4r);
 
-  struct rval_call_bind {
+  struct rval_call_and_then {
-      tl::optional<double> operator()(int) && { return tl::optional<double>(42.0); };
+    tl::optional<double> operator()(int) && {
+      return tl::optional<double>(42.0);
+    };
   };
 
   // ensure that function object is forwarded
   tl::optional<int> o5 = 42;
-  auto o5r = o5.bind(rval_call_bind{});
+  auto o5r = o5.and_then(rval_call_and_then{});
   STATIC_REQUIRE((std::is_same<decltype(o5r), tl::optional<double>>::value));
   REQUIRE(o5r.value() == 42);
 
   // ensure that lhs is forwarded
   tl::optional<int> o6 = 42;
   auto o6r =
-      std::move(o6).bind([](int &&i) { return tl::optional<double>(i); });
+      std::move(o6).and_then([](int &&i) { return tl::optional<double>(i); });
   STATIC_REQUIRE((std::is_same<decltype(o6r), tl::optional<double>>::value));
   REQUIRE(o6r.value() == 42);
 
   // ensure that function object is const-propagated
   const tl::optional<int> o7 = 42;
-  auto o7r = o7.bind([](const int &i) { return tl::optional<double>(i); });
+  auto o7r = o7.and_then([](const int &i) { return tl::optional<double>(i); });
   STATIC_REQUIRE((std::is_same<decltype(o7r), tl::optional<double>>::value));
   REQUIRE(o7r.value() == 42);
 
   // test each overload in turn
   tl::optional<int> o8 = 42;
-  auto o8r = o8.bind([](int i) { return tl::make_optional(42); });
+  auto o8r = o8.and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(*o8r == 42);
 
   tl::optional<int> o9 = 42;
-  auto o9r = std::move(o9).bind([](int i) { return tl::make_optional(42); });
+  auto o9r =
+      std::move(o9).and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(*o9r == 42);
 
   const tl::optional<int> o10 = 42;
-  auto o10r = o10.bind([](int i) { return tl::make_optional(42); });
+  auto o10r = o10.and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(*o10r == 42);
 
   const tl::optional<int> o11 = 42;
-  auto o11r = std::move(o11).bind([](int i) { return tl::make_optional(42); });
+  auto o11r =
+      std::move(o11).and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(*o11r == 42);
 
-  tl::optional<int> o12 = 42;
-  auto o12r = o12.bind([](int i) { return tl::make_optional(42); }, []{return;});
-  REQUIRE(*o12r == 42);
-
-  tl::optional<int> o13 = 42;
-  auto o13r = std::move(o13).bind([](int i) { return tl::make_optional(42); }, []{return;});
-  REQUIRE(*o13r == 42);
-
-  const tl::optional<int> o14 = 42;
-  auto o14r = o14.bind([](int i) { return tl::make_optional(42); }, []{return;});
-  REQUIRE(*o14r == 42);
-
-  const tl::optional<int> o15 = 42;
-  auto o15r = std::move(o15).bind([](int i) { return tl::make_optional(42); }, []{return;});
-  REQUIRE(*o15r == 42);
-
   tl::optional<int> o16 = tl::nullopt;
-  auto o16r = o16.bind([](int i) { return tl::make_optional(42); });
+  auto o16r = o16.and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(!o16r);
 
   tl::optional<int> o17 = tl::nullopt;
-  auto o17r = std::move(o17).bind([](int i) { return tl::make_optional(42); });
+  auto o17r =
+      std::move(o17).and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(!o17r);
 
   const tl::optional<int> o18 = tl::nullopt;
-  auto o18r = o18.bind([](int i) { return tl::make_optional(42); });
+  auto o18r = o18.and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(!o18r);
 
   const tl::optional<int> o19 = tl::nullopt;
-  auto o19r = std::move(o19).bind([](int i) { return tl::make_optional(42); });
+  auto o19r =
+      std::move(o19).and_then([](int i) { return tl::make_optional(42); });
   REQUIRE(!o19r);
-
-  tl::optional<int> o20 = tl::nullopt;
-  bool c20 = false;
-  auto o20r = o20.bind([](int i) { return tl::make_optional(42); }, [&]{c20 = true;});
-  REQUIRE(!o20r);
-  REQUIRE(!c20);
-
-  tl::optional<int> o21 = tl::nullopt;
-  bool c21 = false;
-  auto o21r = std::move(o21).bind([](int i) { return tl::make_optional(42); }, [&]{c21 = true;});
-  REQUIRE(!o21r);
-  REQUIRE(!c21);
-
-  const tl::optional<int> o22 = tl::nullopt;
-  bool c22 = false;
-  auto o22r = o22.bind([](int i) { return tl::make_optional(42); }, [&]{c22 = true;});
-  REQUIRE(!o22r);
-  REQUIRE(!c22);
-
-  const tl::optional<int> o23 = tl::nullopt;
-  bool c23 = false;
-  auto o23r = std::move(o23).bind([](int i) { return tl::make_optional(42); }, [&]{c23 = true;});
-  REQUIRE(!o23r);
-  REQUIRE(!c23);
-
-  tl::optional<int> o24 = 42;
-  bool c24 = false;
-  auto o24r = o24.bind([](int i) { return tl::optional<int>{tl::nullopt}; }, [&]{c24 = true;});
-  REQUIRE(!o24r);
-  REQUIRE(c24);
-
-  tl::optional<int> o25 = 42;
-  bool c25 = false;
-  auto o25r = std::move(o25).bind([](int i) { return tl::optional<int>{tl::nullopt}; }, [&]{c25 = true;});
-  REQUIRE(!o25r);
-  REQUIRE(c25);
-
-  const tl::optional<int> o26 = 42;
-  bool c26 = false;
-  auto o26r = o26.bind([](int i) { return tl::optional<int>{tl::nullopt};}, [&]{c26 = true;});
-  REQUIRE(!o26r);
-  REQUIRE(c26);
-
-  const tl::optional<int> o27 = 42;
-  bool c27 = false;
-  auto o27r = std::move(o27).bind([](int i) { return tl::optional<int>{tl::nullopt};}, [&]{c27 = true;});
-  REQUIRE(!o27r);
-  REQUIRE(c27);
-
 }
 
-SECTION("constexpr bind") {
+SECTION("constexpr and_then") {
   constexpr tl::optional<int> o10 = 42;
-    constexpr auto o10r = o10.bind(get_opt_int);
+  constexpr auto o10r = o10.and_then(get_opt_int);
   REQUIRE(*o10r == 42);
 
   constexpr tl::optional<int> o11 = 42;
-  constexpr auto o11r = std::move(o11).bind(get_opt_int);
+  constexpr auto o11r = std::move(o11).and_then(get_opt_int);
   REQUIRE(*o11r == 42);
 
   constexpr tl::optional<int> o18 = tl::nullopt;
-  constexpr auto o18r = o18.bind(get_opt_int);
+  constexpr auto o18r = o18.and_then(get_opt_int);
   REQUIRE(!o18r);
 
   constexpr tl::optional<int> o19 = tl::nullopt;
-  constexpr auto o19r = std::move(o19).bind(get_opt_int);
+  constexpr auto o19r = std::move(o19).and_then(get_opt_int);
   REQUIRE(!o19r);
 }
+
+SECTION("or else") {
+    //TODO
+}
 }
 ;