From e67066b788d7e1c3b17787c365dbf03b457a6bda Mon Sep 17 00:00:00 2001
From: John Wellbelove <john.wellbelove@asterconsulting.co.uk>
Date: Sat, 2 Aug 2025 13:47:33 +0100
Subject: [PATCH] Added emplace type constructors to etl::optional

---
 include/etl/optional.h  | 96 ++++++++++++++++++++++++++++++++++++++---
 test/test_optional.cpp  | 70 ++++++++++++++++++++++++++++++
 test/vs2022/etl.vcxproj | 30 ++++++-------
 3 files changed, 176 insertions(+), 20 deletions(-)

diff --git a/include/etl/optional.h b/include/etl/optional.h
index f70b2689..4cff15ab 100644
--- a/include/etl/optional.h
+++ b/include/etl/optional.h
@@ -102,7 +102,7 @@ namespace etl
   //*****************************************************************************
   namespace private_optional
   {
-    template <typename T, bool IsDefaultConstructible = etl::is_integral<T>::value>
+    template <typename T, bool IsDefaultConstructible = etl::is_fundamental<T>::value>
     class optional_impl;
 
     //*****************************************************************************
@@ -159,7 +159,6 @@ namespace etl
           storage.construct(etl::move(other.value()));
         }
       }
-#endif
 
       //***************************************************************************
       /// Constructor from value type.
@@ -170,7 +169,6 @@ namespace etl
         storage.construct(value_);
       }
 
-#if ETL_USING_CPP11
       //***************************************************************************
       /// Constructor from value type.
       //***************************************************************************
@@ -179,6 +177,27 @@ namespace etl
       {
         storage.construct(etl::move(value_));
       }
+
+      //***************************************************************************
+      /// Constructor from variadic args.
+      //***************************************************************************
+      template <typename... TArgs>
+      ETL_CONSTEXPR20_STL
+        optional_impl(etl::in_place_t, TArgs&&... args)
+      {
+        storage.construct(etl::forward<TArgs>(args)...);
+      }
+
+      //*******************************************
+      /// Construct from initializer_list and arguments.
+      //*******************************************
+      template <typename U, typename... TArgs >
+      ETL_CONSTEXPR20_STL optional_impl(etl::in_place_t,
+                                        std::initializer_list<U> ilist,
+                                        TArgs&&... args)
+      {
+        storage.construct(ilist, etl::forward<TArgs>(args)...);
+      }
 #endif
 
       //***************************************************************************
@@ -734,7 +753,6 @@ namespace etl
           storage.construct(etl::move(other.value()));
         }
       }
-#endif
 
       //***************************************************************************
       /// Constructor from value type.
@@ -745,7 +763,6 @@ namespace etl
         storage.construct(value_);
       }
 
-#if ETL_USING_CPP11
       //***************************************************************************
       /// Constructor from value type.
       //***************************************************************************
@@ -754,6 +771,27 @@ namespace etl
       {
         storage.construct(etl::move(value_));
       }
+
+      //***************************************************************************
+      /// Constructor from variadic args.
+      //***************************************************************************
+      template <typename... TArgs>
+      ETL_CONSTEXPR14
+        optional_impl(etl::in_place_t, TArgs&&... args)
+      {
+        storage.construct(etl::forward<TArgs>(args)...);
+      }
+
+      //*******************************************
+      /// Construct from initializer_list and arguments.
+      //*******************************************
+      template <typename U, typename... TArgs >
+      ETL_CONSTEXPR14 optional_impl(etl::in_place_t,
+                                    std::initializer_list<U> ilist,
+                                    TArgs&&... args)
+      {
+        storage.construct(ilist, etl::forward<TArgs>(args)...);
+      }
 #endif
 
       //***************************************************************************
@@ -1397,6 +1435,54 @@ namespace etl
     }
 #endif
 
+#if ETL_USING_CPP11
+    //***************************************************************************
+    /// Emplace construct from arguments.
+    //***************************************************************************
+    template <typename U = T, ETL_OPTIONAL_ENABLE_CPP14, typename... Args>
+    ETL_CONSTEXPR14
+    explicit optional(etl::in_place_t, Args&&... args)
+      : impl_t(etl::in_place_t{}, etl::forward<Args>(args)...)
+    {
+    }
+
+    //***************************************************************************
+    /// Emplace construct from arguments.
+    //***************************************************************************
+    template <typename U = T, ETL_OPTIONAL_ENABLE_CPP20_STL, typename... Args>
+    ETL_CONSTEXPR20_STL
+    explicit optional(etl::in_place_t, Args&&... args)
+      : impl_t(etl::in_place_t{}, etl::forward<Args>(args)...)
+    {
+    }
+
+#if ETL_HAS_INITIALIZER_LIST
+    //*******************************************
+    /// Construct from initializer_list and arguments.
+    //*******************************************
+    template <typename U = T, ETL_OPTIONAL_ENABLE_CPP14, typename... TArgs>
+    ETL_CONSTEXPR14 
+    explicit optional(etl::in_place_t,
+                      std::initializer_list<U> ilist,
+                      TArgs&&... args)
+      : impl_t(etl::in_place_t{}, ilist, etl::forward<TArgs>(args)...)
+    {
+    }
+
+    //*******************************************
+    /// Construct from initializer_list and arguments.
+    //*******************************************
+    template <typename U = T, ETL_OPTIONAL_ENABLE_CPP20_STL, typename... TArgs>
+    ETL_CONSTEXPR20_STL 
+    explicit optional(etl::in_place_t,
+                      std::initializer_list<U> ilist,
+                      TArgs&&... args)
+      : impl_t(etl::in_place_t{}, ilist, etl::forward<TArgs>(args)...)
+    {
+    }
+#endif
+#endif
+
 #if ETL_USING_CPP11
     //***************************************************************************
     /// Assignment operator from nullopt.
diff --git a/test/test_optional.cpp b/test/test_optional.cpp
index 87ee24c7..f0ea43ed 100644
--- a/test/test_optional.cpp
+++ b/test/test_optional.cpp
@@ -31,6 +31,7 @@ SOFTWARE.
 #include <string>
 #include <ostream>
 #include <cstdint>
+#include <vector>
 
 #include "etl/optional.h"
 #include "etl/vector.h"
@@ -118,6 +119,75 @@ namespace
       CHECK(!data4.has_value());
     }
 
+#if ETL_USING_CPP14
+    //*************************************************************************
+    TEST(test_emplace_construction_cpp14)
+    {
+      constexpr etl::optional<int> opt(etl::in_place_t{}, 1);
+
+      CHECK_TRUE(opt.has_value());
+      CHECK(bool(opt));
+      CHECK_EQUAL(1, opt.value());
+    }
+#endif
+
+#if ETL_USING_CPP20 && ETL_USING_STL
+    //*************************************************************************
+    TEST(test_emplace_construction_cpp20)
+    {
+      struct TestData
+      {
+        constexpr TestData(int a_, int b_)
+          : a(a_), b(b_)
+        {
+        }
+
+        int a;
+        int b;
+      };
+
+      constexpr etl::optional<TestData> opt(etl::in_place_t{}, 1, 2);
+
+      CHECK_TRUE(opt.has_value());
+      CHECK(bool(opt));
+      CHECK_EQUAL(1, opt.value().a);
+      CHECK_EQUAL(2, opt.value().b);
+    }
+#endif
+
+    //*************************************************************************
+    TEST(test_construct_from_initializer_list_and_arguments)
+    {
+      struct S
+      {
+        S()
+          : vi()
+          , a(0)
+          , b(0)
+        {
+        }
+
+        S(std::initializer_list<int> il, int a_, int b_)
+          : vi(il)
+          , a(a_)
+          , b(b_)
+        {
+        }
+
+        std::vector<int> vi;
+        int a;
+        int b;
+      };
+
+      etl::optional<S> opt(etl::in_place_t{}, { 10, 11, 12 }, 1, 2);
+
+      CHECK_EQUAL(10, opt.value().vi[0]);
+      CHECK_EQUAL(11, opt.value().vi[1]);
+      CHECK_EQUAL(12, opt.value().vi[2]);
+      CHECK_EQUAL(1, opt.value().a);
+      CHECK_EQUAL(2, opt.value().b);
+    }
+
     //*************************************************************************
     TEST(test_deduced_initialisation)
     {
diff --git a/test/vs2022/etl.vcxproj b/test/vs2022/etl.vcxproj
index 721f9bcc..445f32d6 100644
--- a/test/vs2022/etl.vcxproj
+++ b/test/vs2022/etl.vcxproj
@@ -1403,7 +1403,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;_SILENCE_ALL_CXX23_DEPRECATION_WARNINGS;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;_SILENCE_ALL_CXX23_DEPRECATION_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1429,7 +1429,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;_SILENCE_ALL_CXX23_DEPRECATION_WARNINGS;ETL_NO_STL;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;_SILENCE_ALL_CXX23_DEPRECATION_WARNINGS;ETL_NO_STL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1455,7 +1455,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_FORCE_TEST_CPP03_IMPLEMENTATION;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_FORCE_TEST_CPP03_IMPLEMENTATION;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1481,7 +1481,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_FORCE_TEST_CPP03_IMPLEMENTATION;ETL_MESSAGES_ARE_NOT_VIRTUAL;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_FORCE_TEST_CPP03_IMPLEMENTATION;ETL_MESSAGES_ARE_NOT_VIRTUAL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1507,7 +1507,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_MESSAGES_ARE_NOT_VIRTUAL;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_MESSAGES_ARE_NOT_VIRTUAL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1533,7 +1533,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_IMESSAGE_IS_NON_VIRTUAL;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_IMESSAGE_IS_NON_VIRTUAL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1559,7 +1559,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1585,7 +1585,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>MaxSpeed</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1611,7 +1611,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1636,7 +1636,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1661,7 +1661,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1686,7 +1686,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1711,7 +1711,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>MaxSpeed</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1737,7 +1737,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>MaxSpeed</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>
@@ -1948,7 +1948,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;_SILENCE_CXX17_ADAPTOR_TYPEDEFS_DEPRECATION_WARNING;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions);N = 123456789;N</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;_SILENCE_CXX17_ADAPTOR_TYPEDEFS_DEPRECATION_WARNING;ETL_NO_STL;ETL_FORCE_STD_INITIALIZER_LIST;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>./;../../../unittest-cpp/;../../include;../../test</AdditionalIncludeDirectories>
       <UndefinePreprocessorDefinitions>
       </UndefinePreprocessorDefinitions>