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 // Copyright (c) 2017-2024, University of Cincinnati, developed by Henry Schreiner
 // under NSF AWARD 1414736 and by the respective contributors.
 // All rights reserved.
 //
 // SPDX-License-Identifier: BSD-3-Clause
 
 #pragma once
 
 // IWYU pragma: private, include "CLI/CLI.hpp"
 
 // [CLI11:public_includes:set]
 #include <algorithm>
 #include <cmath>
 #include <cstdint>
 #include <exception>
 #include <limits>
 #include <memory>
 #include <string>
 #include <type_traits>
 #include <utility>
 #include <vector>
 // [CLI11:public_includes:end]
 
 #include "Encoding.hpp"
 #include "StringTools.hpp"
 
 namespace CLI {
 // [CLI11:type_tools_hpp:verbatim]
 
 // Type tools
 
 // Utilities for type enabling
 namespace detail {
 // Based generally on https://rmf.io/cxx11/almost-static-if
 /// Simple empty scoped class
 enum class enabler {};
 
 /// An instance to use in EnableIf
 constexpr enabler dummy = {};
 }  // namespace detail
 
 /// A copy of enable_if_t from C++14, compatible with C++11.
 ///
 /// We could check to see if C++14 is being used, but it does not hurt to redefine this
 /// (even Google does this: https://github.com/google/skia/blob/main/include/private/SkTLogic.h)
 /// It is not in the std namespace anyway, so no harm done.
 template <bool B, class T = void> using enable_if_t = typename std::enable_if<B, T>::type;
 
 /// A copy of std::void_t from C++17 (helper for C++11 and C++14)
 template <typename... Ts> struct make_void {
     using type = void;
 };
 
 /// A copy of std::void_t from C++17 - same reasoning as enable_if_t, it does not hurt to redefine
 template <typename... Ts> using void_t = typename make_void<Ts...>::type;
 
 /// A copy of std::conditional_t from C++14 - same reasoning as enable_if_t, it does not hurt to redefine
 template <bool B, class T, class F> using conditional_t = typename std::conditional<B, T, F>::type;
 
 /// Check to see if something is bool (fail check by default)
 template <typename T> struct is_bool : std::false_type {};
 
 /// Check to see if something is bool (true if actually a bool)
 template <> struct is_bool<bool> : std::true_type {};
 
 /// Check to see if something is a shared pointer
 template <typename T> struct is_shared_ptr : std::false_type {};
 
 /// Check to see if something is a shared pointer (True if really a shared pointer)
 template <typename T> struct is_shared_ptr<std::shared_ptr<T>> : std::true_type {};
 
 /// Check to see if something is a shared pointer (True if really a shared pointer)
 template <typename T> struct is_shared_ptr<const std::shared_ptr<T>> : std::true_type {};
 
 /// Check to see if something is copyable pointer
 template <typename T> struct is_copyable_ptr {
     static bool const value = is_shared_ptr<T>::value || std::is_pointer<T>::value;
 };
 
 /// This can be specialized to override the type deduction for IsMember.
 template <typename T> struct IsMemberType {
     using type = T;
 };
 
 /// The main custom type needed here is const char * should be a string.
 template <> struct IsMemberType<const char *> {
     using type = std::string;
 };
 
 namespace adl_detail {
 /// Check for existence of user-supplied lexical_cast.
 ///
 /// This struct has to be in a separate namespace so that it doesn't see our lexical_cast overloads in CLI::detail.
 /// Standard says it shouldn't see them if it's defined before the corresponding lexical_cast declarations, but this
 /// requires a working implementation of two-phase lookup, and not all compilers can boast that (msvc, ahem).
 template <typename T, typename S = std::string> class is_lexical_castable {
     template <typename TT, typename SS>
     static auto test(int) -> decltype(lexical_cast(std::declval<const SS &>(), std::declval<TT &>()), std::true_type());
 
     template <typename, typename> static auto test(...) -> std::false_type;
 
   public:
     static constexpr bool value = decltype(test<T, S>(0))::value;
 };
 }  // namespace adl_detail
 
 namespace detail {
 
 // These are utilities for IsMember and other transforming objects
 
 /// Handy helper to access the element_type generically. This is not part of is_copyable_ptr because it requires that
 /// pointer_traits<T> be valid.
 
 /// not a pointer
 template <typename T, typename Enable = void> struct element_type {
     using type = T;
 };
 
 template <typename T> struct element_type<T, typename std::enable_if<is_copyable_ptr<T>::value>::type> {
     using type = typename std::pointer_traits<T>::element_type;
 };
 
 /// Combination of the element type and value type - remove pointer (including smart pointers) and get the value_type of
 /// the container
 template <typename T> struct element_value_type {
     using type = typename element_type<T>::type::value_type;
 };
 
 /// Adaptor for set-like structure: This just wraps a normal container in a few utilities that do almost nothing.
 template <typename T, typename _ = void> struct pair_adaptor : std::false_type {
     using value_type = typename T::value_type;
     using first_type = typename std::remove_const<value_type>::type;
     using second_type = typename std::remove_const<value_type>::type;
 
     /// Get the first value (really just the underlying value)
     template <typename Q> static auto first(Q &&pair_value) -> decltype(std::forward<Q>(pair_value)) {
         return std::forward<Q>(pair_value);
     }
     /// Get the second value (really just the underlying value)
     template <typename Q> static auto second(Q &&pair_value) -> decltype(std::forward<Q>(pair_value)) {
         return std::forward<Q>(pair_value);
     }
 };
 
 /// Adaptor for map-like structure (true version, must have key_type and mapped_type).
 /// This wraps a mapped container in a few utilities access it in a general way.
 template <typename T>
 struct pair_adaptor<
     T,
     conditional_t<false, void_t<typename T::value_type::first_type, typename T::value_type::second_type>, void>>
     : std::true_type {
     using value_type = typename T::value_type;
     using first_type = typename std::remove_const<typename value_type::first_type>::type;
     using second_type = typename std::remove_const<typename value_type::second_type>::type;
 
     /// Get the first value (really just the underlying value)
     template <typename Q> static auto first(Q &&pair_value) -> decltype(std::get<0>(std::forward<Q>(pair_value))) {
         return std::get<0>(std::forward<Q>(pair_value));
     }
     /// Get the second value (really just the underlying value)
     template <typename Q> static auto second(Q &&pair_value) -> decltype(std::get<1>(std::forward<Q>(pair_value))) {
         return std::get<1>(std::forward<Q>(pair_value));
     }
 };
 
 // Warning is suppressed due to "bug" in gcc<5.0 and gcc 7.0 with c++17 enabled that generates a Wnarrowing warning
 // in the unevaluated context even if the function that was using this wasn't used.  The standard says narrowing in
 // brace initialization shouldn't be allowed but for backwards compatibility gcc allows it in some contexts.  It is a
 // little fuzzy what happens in template constructs and I think that was something GCC took a little while to work out.
 // But regardless some versions of gcc generate a warning when they shouldn't from the following code so that should be
 // suppressed
 #ifdef __GNUC__
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wnarrowing"
 #endif
 // check for constructibility from a specific type and copy assignable used in the parse detection
 template <typename T, typename C> class is_direct_constructible {
     template <typename TT, typename CC>
     static auto test(int, std::true_type) -> decltype(
 // NVCC warns about narrowing conversions here
 #ifdef __CUDACC__
 #ifdef __NVCC_DIAG_PRAGMA_SUPPORT__
 #pragma nv_diag_suppress 2361
 #else
 #pragma diag_suppress 2361
 #endif
 #endif
                                               TT{std::declval<CC>()}
 #ifdef __CUDACC__
 #ifdef __NVCC_DIAG_PRAGMA_SUPPORT__
 #pragma nv_diag_default 2361
 #else
 #pragma diag_default 2361
 #endif
 #endif
                                               ,
                                               std::is_move_assignable<TT>());
 
     template <typename TT, typename CC> static auto test(int, std::false_type) -> std::false_type;
 
     template <typename, typename> static auto test(...) -> std::false_type;
 
   public:
     static constexpr bool value = decltype(test<T, C>(0, typename std::is_constructible<T, C>::type()))::value;
 };
 #ifdef __GNUC__
 #pragma GCC diagnostic pop
 #endif
 
 // Check for output streamability
 // Based on https://stackoverflow.com/questions/22758291/how-can-i-detect-if-a-type-can-be-streamed-to-an-stdostream
 
 template <typename T, typename S = std::ostringstream> class is_ostreamable {
     template <typename TT, typename SS>
     static auto test(int) -> decltype(std::declval<SS &>() << std::declval<TT>(), std::true_type());
 
     template <typename, typename> static auto test(...) -> std::false_type;
 
   public:
     static constexpr bool value = decltype(test<T, S>(0))::value;
 };
 
 /// Check for input streamability
 template <typename T, typename S = std::istringstream> class is_istreamable {
     template <typename TT, typename SS>
     static auto test(int) -> decltype(std::declval<SS &>() >> std::declval<TT &>(), std::true_type());
 
     template <typename, typename> static auto test(...) -> std::false_type;
 
   public:
     static constexpr bool value = decltype(test<T, S>(0))::value;
 };
 
 /// Check for complex
 template <typename T> class is_complex {
     template <typename TT>
     static auto test(int) -> decltype(std::declval<TT>().real(), std::declval<TT>().imag(), std::true_type());
 
     template <typename> static auto test(...) -> std::false_type;
 
   public:
     static constexpr bool value = decltype(test<T>(0))::value;
 };
 
 /// Templated operation to get a value from a stream
 template <typename T, enable_if_t<is_istreamable<T>::value, detail::enabler> = detail::dummy>
 bool from_stream(const std::string &istring, T &obj) {
     std::istringstream is;
     is.str(istring);
     is >> obj;
     return !is.fail() && !is.rdbuf()->in_avail();
 }
 
 template <typename T, enable_if_t<!is_istreamable<T>::value, detail::enabler> = detail::dummy>
 bool from_stream(const std::string & /*istring*/, T & /*obj*/) {
     return false;
 }
 
 // check to see if an object is a mutable container (fail by default)
 template <typename T, typename _ = void> struct is_mutable_container : std::false_type {};
 
 /// type trait to test if a type is a mutable container meaning it has a value_type, it has an iterator, a clear, and
 /// end methods and an insert function.  And for our purposes we exclude std::string and types that can be constructed
 /// from a std::string
 template <typename T>
 struct is_mutable_container<
     T,
     conditional_t<false,
                   void_t<typename T::value_type,
                          decltype(std::declval<T>().end()),
                          decltype(std::declval<T>().clear()),
                          decltype(std::declval<T>().insert(std::declval<decltype(std::declval<T>().end())>(),
                                                            std::declval<const typename T::value_type &>()))>,
                   void>> : public conditional_t<std::is_constructible<T, std::string>::value ||
                                                     std::is_constructible<T, std::wstring>::value,
                                                 std::false_type,
                                                 std::true_type> {};
 
 // check to see if an object is a mutable container (fail by default)
 template <typename T, typename _ = void> struct is_readable_container : std::false_type {};
 
 /// type trait to test if a type is a container meaning it has a value_type, it has an iterator, a clear, and an end
 /// methods and an insert function.  And for our purposes we exclude std::string and types that can be constructed from
 /// a std::string
 template <typename T>
 struct is_readable_container<
     T,
     conditional_t<false, void_t<decltype(std::declval<T>().end()), decltype(std::declval<T>().begin())>, void>>
     : public std::true_type {};
 
 // check to see if an object is a wrapper (fail by default)
 template <typename T, typename _ = void> struct is_wrapper : std::false_type {};
 
 // check if an object is a wrapper (it has a value_type defined)
 template <typename T>
 struct is_wrapper<T, conditional_t<false, void_t<typename T::value_type>, void>> : public std::true_type {};
 
 // Check for tuple like types, as in classes with a tuple_size type trait
 template <typename S> class is_tuple_like {
     template <typename SS>
     // static auto test(int)
     //     -> decltype(std::conditional<(std::tuple_size<SS>::value > 0), std::true_type, std::false_type>::type());
     static auto test(int) -> decltype(std::tuple_size<typename std::decay<SS>::type>::value, std::true_type{});
     template <typename> static auto test(...) -> std::false_type;
 
   public:
     static constexpr bool value = decltype(test<S>(0))::value;
 };
 
 /// Convert an object to a string (directly forward if this can become a string)
 template <typename T, enable_if_t<std::is_convertible<T, std::string>::value, detail::enabler> = detail::dummy>
 auto to_string(T &&value) -> decltype(std::forward<T>(value)) {
     return std::forward<T>(value);
 }
 
 /// Construct a string from the object
 template <typename T,
           enable_if_t<std::is_constructible<std::string, T>::value && !std::is_convertible<T, std::string>::value,
                       detail::enabler> = detail::dummy>
 std::string to_string(const T &value) {
     return std::string(value);  // NOLINT(google-readability-casting)
 }
 
 /// Convert an object to a string (streaming must be supported for that type)
 template <typename T,
           enable_if_t<!std::is_convertible<std::string, T>::value && !std::is_constructible<std::string, T>::value &&
                           is_ostreamable<T>::value,
                       detail::enabler> = detail::dummy>
 std::string to_string(T &&value) {
     std::stringstream stream;
     stream << value;
     return stream.str();
 }
 
 /// If conversion is not supported, return an empty string (streaming is not supported for that type)
 template <typename T,
           enable_if_t<!std::is_constructible<std::string, T>::value && !is_ostreamable<T>::value &&
                           !is_readable_container<typename std::remove_const<T>::type>::value,
                       detail::enabler> = detail::dummy>
 std::string to_string(T &&) {
     return {};
 }
 
 /// convert a readable container to a string
 template <typename T,
           enable_if_t<!std::is_constructible<std::string, T>::value && !is_ostreamable<T>::value &&
                           is_readable_container<T>::value,
                       detail::enabler> = detail::dummy>
 std::string to_string(T &&variable) {
     auto cval = variable.begin();
     auto end = variable.end();
     if(cval == end) {
         return {"{}"};
     }
     std::vector<std::string> defaults;
     while(cval != end) {
         defaults.emplace_back(CLI::detail::to_string(*cval));
         ++cval;
     }
     return {"[" + detail::join(defaults) + "]"};
 }
 
 /// special template overload
 template <typename T1,
           typename T2,
           typename T,
           enable_if_t<std::is_same<T1, T2>::value, detail::enabler> = detail::dummy>
 auto checked_to_string(T &&value) -> decltype(to_string(std::forward<T>(value))) {
     return to_string(std::forward<T>(value));
 }
 
 /// special template overload
 template <typename T1,
           typename T2,
           typename T,
           enable_if_t<!std::is_same<T1, T2>::value, detail::enabler> = detail::dummy>
 std::string checked_to_string(T &&) {
     return std::string{};
 }
 /// get a string as a convertible value for arithmetic types
 template <typename T, enable_if_t<std::is_arithmetic<T>::value, detail::enabler> = detail::dummy>
 std::string value_string(const T &value) {
     return std::to_string(value);
 }
 /// get a string as a convertible value for enumerations
 template <typename T, enable_if_t<std::is_enum<T>::value, detail::enabler> = detail::dummy>
 std::string value_string(const T &value) {
     return std::to_string(static_cast<typename std::underlying_type<T>::type>(value));
 }
 /// for other types just use the regular to_string function
 template <typename T,
           enable_if_t<!std::is_enum<T>::value && !std::is_arithmetic<T>::value, detail::enabler> = detail::dummy>
 auto value_string(const T &value) -> decltype(to_string(value)) {
     return to_string(value);
 }
 
 /// template to get the underlying value type if it exists or use a default
 template <typename T, typename def, typename Enable = void> struct wrapped_type {
     using type = def;
 };
 
 /// Type size for regular object types that do not look like a tuple
 template <typename T, typename def> struct wrapped_type<T, def, typename std::enable_if<is_wrapper<T>::value>::type> {
     using type = typename T::value_type;
 };
 
 /// This will only trigger for actual void type
 template <typename T, typename Enable = void> struct type_count_base {
     static const int value{0};
 };
 
 /// Type size for regular object types that do not look like a tuple
 template <typename T>
 struct type_count_base<T,
                        typename std::enable_if<!is_tuple_like<T>::value && !is_mutable_container<T>::value &&
                                                !std::is_void<T>::value>::type> {
     static constexpr int value{1};
 };
 
 /// the base tuple size
 template <typename T>
 struct type_count_base<T, typename std::enable_if<is_tuple_like<T>::value && !is_mutable_container<T>::value>::type> {
     static constexpr int value{std::tuple_size<T>::value};
 };
 
 /// Type count base for containers is the type_count_base of the individual element
 template <typename T> struct type_count_base<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
     static constexpr int value{type_count_base<typename T::value_type>::value};
 };
 
 /// Set of overloads to get the type size of an object
 
 /// forward declare the subtype_count structure
 template <typename T> struct subtype_count;
 
 /// forward declare the subtype_count_min structure
 template <typename T> struct subtype_count_min;
 
 /// This will only trigger for actual void type
 template <typename T, typename Enable = void> struct type_count {
     static const int value{0};
 };
 
 /// Type size for regular object types that do not look like a tuple
 template <typename T>
 struct type_count<T,
                   typename std::enable_if<!is_wrapper<T>::value && !is_tuple_like<T>::value && !is_complex<T>::value &&
                                           !std::is_void<T>::value>::type> {
     static constexpr int value{1};
 };
 
 /// Type size for complex since it sometimes looks like a wrapper
 template <typename T> struct type_count<T, typename std::enable_if<is_complex<T>::value>::type> {
     static constexpr int value{2};
 };
 
 /// Type size of types that are wrappers,except complex and tuples(which can also be wrappers sometimes)
 template <typename T> struct type_count<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
     static constexpr int value{subtype_count<typename T::value_type>::value};
 };
 
 /// Type size of types that are wrappers,except containers complex and tuples(which can also be wrappers sometimes)
 template <typename T>
 struct type_count<T,
                   typename std::enable_if<is_wrapper<T>::value && !is_complex<T>::value && !is_tuple_like<T>::value &&
                                           !is_mutable_container<T>::value>::type> {
     static constexpr int value{type_count<typename T::value_type>::value};
 };
 
 /// 0 if the index > tuple size
 template <typename T, std::size_t I>
 constexpr typename std::enable_if<I == type_count_base<T>::value, int>::type tuple_type_size() {
     return 0;
 }
 
 /// Recursively generate the tuple type name
 template <typename T, std::size_t I>
     constexpr typename std::enable_if < I<type_count_base<T>::value, int>::type tuple_type_size() {
     return subtype_count<typename std::tuple_element<I, T>::type>::value + tuple_type_size<T, I + 1>();
 }
 
 /// Get the type size of the sum of type sizes for all the individual tuple types
 template <typename T> struct type_count<T, typename std::enable_if<is_tuple_like<T>::value>::type> {
     static constexpr int value{tuple_type_size<T, 0>()};
 };
 
 /// definition of subtype count
 template <typename T> struct subtype_count {
     static constexpr int value{is_mutable_container<T>::value ? expected_max_vector_size : type_count<T>::value};
 };
 
 /// This will only trigger for actual void type
 template <typename T, typename Enable = void> struct type_count_min {
     static const int value{0};
 };
 
 /// Type size for regular object types that do not look like a tuple
 template <typename T>
 struct type_count_min<
     T,
     typename std::enable_if<!is_mutable_container<T>::value && !is_tuple_like<T>::value && !is_wrapper<T>::value &&
                             !is_complex<T>::value && !std::is_void<T>::value>::type> {
     static constexpr int value{type_count<T>::value};
 };
 
 /// Type size for complex since it sometimes looks like a wrapper
 template <typename T> struct type_count_min<T, typename std::enable_if<is_complex<T>::value>::type> {
     static constexpr int value{1};
 };
 
 /// Type size min of types that are wrappers,except complex and tuples(which can also be wrappers sometimes)
 template <typename T>
 struct type_count_min<
     T,
     typename std::enable_if<is_wrapper<T>::value && !is_complex<T>::value && !is_tuple_like<T>::value>::type> {
     static constexpr int value{subtype_count_min<typename T::value_type>::value};
 };
 
 /// 0 if the index > tuple size
 template <typename T, std::size_t I>
 constexpr typename std::enable_if<I == type_count_base<T>::value, int>::type tuple_type_size_min() {
     return 0;
 }
 
 /// Recursively generate the tuple type name
 template <typename T, std::size_t I>
     constexpr typename std::enable_if < I<type_count_base<T>::value, int>::type tuple_type_size_min() {
     return subtype_count_min<typename std::tuple_element<I, T>::type>::value + tuple_type_size_min<T, I + 1>();
 }
 
 /// Get the type size of the sum of type sizes for all the individual tuple types
 template <typename T> struct type_count_min<T, typename std::enable_if<is_tuple_like<T>::value>::type> {
     static constexpr int value{tuple_type_size_min<T, 0>()};
 };
 
 /// definition of subtype count
 template <typename T> struct subtype_count_min {
     static constexpr int value{is_mutable_container<T>::value
                                    ? ((type_count<T>::value < expected_max_vector_size) ? type_count<T>::value : 0)
                                    : type_count_min<T>::value};
 };
 
 /// This will only trigger for actual void type
 template <typename T, typename Enable = void> struct expected_count {
     static const int value{0};
 };
 
 /// For most types the number of expected items is 1
 template <typename T>
 struct expected_count<T,
                       typename std::enable_if<!is_mutable_container<T>::value && !is_wrapper<T>::value &&
                                               !std::is_void<T>::value>::type> {
     static constexpr int value{1};
 };
 /// number of expected items in a vector
 template <typename T> struct expected_count<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
     static constexpr int value{expected_max_vector_size};
 };
 
 /// number of expected items in a vector
 template <typename T>
 struct expected_count<T, typename std::enable_if<!is_mutable_container<T>::value && is_wrapper<T>::value>::type> {
     static constexpr int value{expected_count<typename T::value_type>::value};
 };
 
 // Enumeration of the different supported categorizations of objects
 enum class object_category : int {
     char_value = 1,
     integral_value = 2,
     unsigned_integral = 4,
     enumeration = 6,
     boolean_value = 8,
     floating_point = 10,
     number_constructible = 12,
     double_constructible = 14,
     integer_constructible = 16,
     // string like types
     string_assignable = 23,
     string_constructible = 24,
     wstring_assignable = 25,
     wstring_constructible = 26,
     other = 45,
     // special wrapper or container types
     wrapper_value = 50,
     complex_number = 60,
     tuple_value = 70,
     container_value = 80,
 
 };
 
 /// Set of overloads to classify an object according to type
 
 /// some type that is not otherwise recognized
 template <typename T, typename Enable = void> struct classify_object {
     static constexpr object_category value{object_category::other};
 };
 
 /// Signed integers
 template <typename T>
 struct classify_object<
     T,
     typename std::enable_if<std::is_integral<T>::value && !std::is_same<T, char>::value && std::is_signed<T>::value &&
                             !is_bool<T>::value && !std::is_enum<T>::value>::type> {
     static constexpr object_category value{object_category::integral_value};
 };
 
 /// Unsigned integers
 template <typename T>
 struct classify_object<T,
                        typename std::enable_if<std::is_integral<T>::value && std::is_unsigned<T>::value &&
                                                !std::is_same<T, char>::value && !is_bool<T>::value>::type> {
     static constexpr object_category value{object_category::unsigned_integral};
 };
 
 /// single character values
 template <typename T>
 struct classify_object<T, typename std::enable_if<std::is_same<T, char>::value && !std::is_enum<T>::value>::type> {
     static constexpr object_category value{object_category::char_value};
 };
 
 /// Boolean values
 template <typename T> struct classify_object<T, typename std::enable_if<is_bool<T>::value>::type> {
     static constexpr object_category value{object_category::boolean_value};
 };
 
 /// Floats
 template <typename T> struct classify_object<T, typename std::enable_if<std::is_floating_point<T>::value>::type> {
     static constexpr object_category value{object_category::floating_point};
 };
 #if defined _MSC_VER
 // in MSVC wstring should take precedence if available this isn't as useful on other compilers due to the broader use of
 // utf-8 encoding
 #define WIDE_STRING_CHECK                                                                                              \
     !std::is_assignable<T &, std::wstring>::value && !std::is_constructible<T, std::wstring>::value
 #define STRING_CHECK true
 #else
 #define WIDE_STRING_CHECK true
 #define STRING_CHECK !std::is_assignable<T &, std::string>::value && !std::is_constructible<T, std::string>::value
 #endif
 
 /// String and similar direct assignment
 template <typename T>
 struct classify_object<
     T,
     typename std::enable_if<!std::is_floating_point<T>::value && !std::is_integral<T>::value && WIDE_STRING_CHECK &&
                             std::is_assignable<T &, std::string>::value>::type> {
     static constexpr object_category value{object_category::string_assignable};
 };
 
 /// String and similar constructible and copy assignment
 template <typename T>
 struct classify_object<
     T,
     typename std::enable_if<!std::is_floating_point<T>::value && !std::is_integral<T>::value &&
                             !std::is_assignable<T &, std::string>::value && (type_count<T>::value == 1) &&
                             WIDE_STRING_CHECK && std::is_constructible<T, std::string>::value>::type> {
     static constexpr object_category value{object_category::string_constructible};
 };
 
 /// Wide strings
 template <typename T>
 struct classify_object<T,
                        typename std::enable_if<!std::is_floating_point<T>::value && !std::is_integral<T>::value &&
                                                STRING_CHECK && std::is_assignable<T &, std::wstring>::value>::type> {
     static constexpr object_category value{object_category::wstring_assignable};
 };
 
 template <typename T>
 struct classify_object<
     T,
     typename std::enable_if<!std::is_floating_point<T>::value && !std::is_integral<T>::value &&
                             !std::is_assignable<T &, std::wstring>::value && (type_count<T>::value == 1) &&
                             STRING_CHECK && std::is_constructible<T, std::wstring>::value>::type> {
     static constexpr object_category value{object_category::wstring_constructible};
 };
 
 /// Enumerations
 template <typename T> struct classify_object<T, typename std::enable_if<std::is_enum<T>::value>::type> {
     static constexpr object_category value{object_category::enumeration};
 };
 
 template <typename T> struct classify_object<T, typename std::enable_if<is_complex<T>::value>::type> {
     static constexpr object_category value{object_category::complex_number};
 };
 
 /// Handy helper to contain a bunch of checks that rule out many common types (integers, string like, floating point,
 /// vectors, and enumerations
 template <typename T> struct uncommon_type {
     using type = typename std::conditional<
         !std::is_floating_point<T>::value && !std::is_integral<T>::value &&
             !std::is_assignable<T &, std::string>::value && !std::is_constructible<T, std::string>::value &&
             !std::is_assignable<T &, std::wstring>::value && !std::is_constructible<T, std::wstring>::value &&
             !is_complex<T>::value && !is_mutable_container<T>::value && !std::is_enum<T>::value,
         std::true_type,
         std::false_type>::type;
     static constexpr bool value = type::value;
 };
 
 /// wrapper type
 template <typename T>
 struct classify_object<T,
                        typename std::enable_if<(!is_mutable_container<T>::value && is_wrapper<T>::value &&
                                                 !is_tuple_like<T>::value && uncommon_type<T>::value)>::type> {
     static constexpr object_category value{object_category::wrapper_value};
 };
 
 /// Assignable from double or int
 template <typename T>
 struct classify_object<T,
                        typename std::enable_if<uncommon_type<T>::value && type_count<T>::value == 1 &&
                                                !is_wrapper<T>::value && is_direct_constructible<T, double>::value &&
                                                is_direct_constructible<T, int>::value>::type> {
     static constexpr object_category value{object_category::number_constructible};
 };
 
 /// Assignable from int
 template <typename T>
 struct classify_object<T,
                        typename std::enable_if<uncommon_type<T>::value && type_count<T>::value == 1 &&
                                                !is_wrapper<T>::value && !is_direct_constructible<T, double>::value &&
                                                is_direct_constructible<T, int>::value>::type> {
     static constexpr object_category value{object_category::integer_constructible};
 };
 
 /// Assignable from double
 template <typename T>
 struct classify_object<T,
                        typename std::enable_if<uncommon_type<T>::value && type_count<T>::value == 1 &&
                                                !is_wrapper<T>::value && is_direct_constructible<T, double>::value &&
                                                !is_direct_constructible<T, int>::value>::type> {
     static constexpr object_category value{object_category::double_constructible};
 };
 
 /// Tuple type
 template <typename T>
 struct classify_object<
     T,
     typename std::enable_if<is_tuple_like<T>::value &&
                             ((type_count<T>::value >= 2 && !is_wrapper<T>::value) ||
                              (uncommon_type<T>::value && !is_direct_constructible<T, double>::value &&
                               !is_direct_constructible<T, int>::value) ||
                              (uncommon_type<T>::value && type_count<T>::value >= 2))>::type> {
     static constexpr object_category value{object_category::tuple_value};
     // the condition on this class requires it be like a tuple, but on some compilers (like Xcode) tuples can be
     // constructed from just the first element so tuples of <string, int,int> can be constructed from a string, which
     // could lead to issues so there are two variants of the condition, the first isolates things with a type size >=2
     // mainly to get tuples on Xcode with the exception of wrappers, the second is the main one and just separating out
     // those cases that are caught by other object classifications
 };
 
 /// container type
 template <typename T> struct classify_object<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
     static constexpr object_category value{object_category::container_value};
 };
 
 // Type name print
 
 /// Was going to be based on
 ///  http://stackoverflow.com/questions/1055452/c-get-name-of-type-in-template
 /// But this is cleaner and works better in this case
 
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::char_value, detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "CHAR";
 }
 
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::integral_value ||
                           classify_object<T>::value == object_category::integer_constructible,
                       detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "INT";
 }
 
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::unsigned_integral, detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "UINT";
 }
 
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::floating_point ||
                           classify_object<T>::value == object_category::number_constructible ||
                           classify_object<T>::value == object_category::double_constructible,
                       detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "FLOAT";
 }
 
 /// Print name for enumeration types
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::enumeration, detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "ENUM";
 }
 
 /// Print name for enumeration types
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::boolean_value, detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "BOOLEAN";
 }
 
 /// Print name for enumeration types
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::complex_number, detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "COMPLEX";
 }
 
 /// Print for all other types
 template <typename T,
           enable_if_t<classify_object<T>::value >= object_category::string_assignable &&
                           classify_object<T>::value <= object_category::other,
                       detail::enabler> = detail::dummy>
 constexpr const char *type_name() {
     return "TEXT";
 }
 /// typename for tuple value
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::tuple_value && type_count_base<T>::value >= 2,
                       detail::enabler> = detail::dummy>
 std::string type_name();  // forward declaration
 
 /// Generate type name for a wrapper or container value
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::container_value ||
                           classify_object<T>::value == object_category::wrapper_value,
                       detail::enabler> = detail::dummy>
 std::string type_name();  // forward declaration
 
 /// Print name for single element tuple types
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::tuple_value && type_count_base<T>::value == 1,
                       detail::enabler> = detail::dummy>
 inline std::string type_name() {
     return type_name<typename std::decay<typename std::tuple_element<0, T>::type>::type>();
 }
 
 /// Empty string if the index > tuple size
 template <typename T, std::size_t I>
 inline typename std::enable_if<I == type_count_base<T>::value, std::string>::type tuple_name() {
     return std::string{};
 }
 
 /// Recursively generate the tuple type name
 template <typename T, std::size_t I>
 inline typename std::enable_if<(I < type_count_base<T>::value), std::string>::type tuple_name() {
     auto str = std::string{type_name<typename std::decay<typename std::tuple_element<I, T>::type>::type>()} + ',' +
                tuple_name<T, I + 1>();
     if(str.back() == ',')
         str.pop_back();
     return str;
 }
 
 /// Print type name for tuples with 2 or more elements
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::tuple_value && type_count_base<T>::value >= 2,
                       detail::enabler>>
 inline std::string type_name() {
     auto tname = std::string(1, '[') + tuple_name<T, 0>();
     tname.push_back(']');
     return tname;
 }
 
 /// get the type name for a type that has a value_type member
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::container_value ||
                           classify_object<T>::value == object_category::wrapper_value,
                       detail::enabler>>
 inline std::string type_name() {
     return type_name<typename T::value_type>();
 }
 
 // Lexical cast
 
 /// Convert to an unsigned integral
 template <typename T, enable_if_t<std::is_unsigned<T>::value, detail::enabler> = detail::dummy>
 bool integral_conversion(const std::string &input, T &output) noexcept {
     if(input.empty() || input.front() == '-') {
         return false;
     }
     char *val{nullptr};
     errno = 0;
     std::uint64_t output_ll = std::strtoull(input.c_str(), &val, 0);
     if(errno == ERANGE) {
         return false;
     }
     output = static_cast<T>(output_ll);
     if(val == (input.c_str() + input.size()) && static_cast<std::uint64_t>(output) == output_ll) {
         return true;
     }
     val = nullptr;
     std::int64_t output_sll = std::strtoll(input.c_str(), &val, 0);
     if(val == (input.c_str() + input.size())) {
         output = (output_sll < 0) ? static_cast<T>(0) : static_cast<T>(output_sll);
         return (static_cast<std::int64_t>(output) == output_sll);
     }
     // remove separators
     if(input.find_first_of("_'") != std::string::npos) {
         std::string nstring = input;
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '_'), nstring.end());
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '\''), nstring.end());
         return integral_conversion(nstring, output);
     }
     if(input.compare(0, 2, "0o") == 0) {
         val = nullptr;
         errno = 0;
         output_ll = std::strtoull(input.c_str() + 2, &val, 8);
         if(errno == ERANGE) {
             return false;
         }
         output = static_cast<T>(output_ll);
         return (val == (input.c_str() + input.size()) && static_cast<std::uint64_t>(output) == output_ll);
     }
     if(input.compare(0, 2, "0b") == 0) {
         val = nullptr;
         errno = 0;
         output_ll = std::strtoull(input.c_str() + 2, &val, 2);
         if(errno == ERANGE) {
             return false;
         }
         output = static_cast<T>(output_ll);
         return (val == (input.c_str() + input.size()) && static_cast<std::uint64_t>(output) == output_ll);
     }
     return false;
 }
 
 /// Convert to a signed integral
 template <typename T, enable_if_t<std::is_signed<T>::value, detail::enabler> = detail::dummy>
 bool integral_conversion(const std::string &input, T &output) noexcept {
     if(input.empty()) {
         return false;
     }
     char *val = nullptr;
     errno = 0;
     std::int64_t output_ll = std::strtoll(input.c_str(), &val, 0);
     if(errno == ERANGE) {
         return false;
     }
     output = static_cast<T>(output_ll);
     if(val == (input.c_str() + input.size()) && static_cast<std::int64_t>(output) == output_ll) {
         return true;
     }
     if(input == "true") {
         // this is to deal with a few oddities with flags and wrapper int types
         output = static_cast<T>(1);
         return true;
     }
     // remove separators
     if(input.find_first_of("_'") != std::string::npos) {
         std::string nstring = input;
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '_'), nstring.end());
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '\''), nstring.end());
         return integral_conversion(nstring, output);
     }
     if(input.compare(0, 2, "0o") == 0) {
         val = nullptr;
         errno = 0;
         output_ll = std::strtoll(input.c_str() + 2, &val, 8);
         if(errno == ERANGE) {
             return false;
         }
         output = static_cast<T>(output_ll);
         return (val == (input.c_str() + input.size()) && static_cast<std::int64_t>(output) == output_ll);
     }
     if(input.compare(0, 2, "0b") == 0) {
         val = nullptr;
         errno = 0;
         output_ll = std::strtoll(input.c_str() + 2, &val, 2);
         if(errno == ERANGE) {
             return false;
         }
         output = static_cast<T>(output_ll);
         return (val == (input.c_str() + input.size()) && static_cast<std::int64_t>(output) == output_ll);
     }
     return false;
 }
 
 /// Convert a flag into an integer value  typically binary flags sets errno to nonzero if conversion failed
 inline std::int64_t to_flag_value(std::string val) noexcept {
     static const std::string trueString("true");
     static const std::string falseString("false");
     if(val == trueString) {
         return 1;
     }
     if(val == falseString) {
         return -1;
     }
     val = detail::to_lower(val);
     std::int64_t ret = 0;
     if(val.size() == 1) {
         if(val[0] >= '1' && val[0] <= '9') {
             return (static_cast<std::int64_t>(val[0]) - '0');
         }
         switch(val[0]) {
         case '0':
         case 'f':
         case 'n':
         case '-':
             ret = -1;
             break;
         case 't':
         case 'y':
         case '+':
             ret = 1;
             break;
         default:
             errno = EINVAL;
             return -1;
         }
         return ret;
     }
     if(val == trueString || val == "on" || val == "yes" || val == "enable") {
         ret = 1;
     } else if(val == falseString || val == "off" || val == "no" || val == "disable") {
         ret = -1;
     } else {
         char *loc_ptr{nullptr};
         ret = std::strtoll(val.c_str(), &loc_ptr, 0);
         if(loc_ptr != (val.c_str() + val.size()) && errno == 0) {
             errno = EINVAL;
         }
     }
     return ret;
 }
 
 /// Integer conversion
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::integral_value ||
                           classify_object<T>::value == object_category::unsigned_integral,
                       detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     return integral_conversion(input, output);
 }
 
 /// char values
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::char_value, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     if(input.size() == 1) {
         output = static_cast<T>(input[0]);
         return true;
     }
     return integral_conversion(input, output);
 }
 
 /// Boolean values
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::boolean_value, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     errno = 0;
     auto out = to_flag_value(input);
     if(errno == 0) {
         output = (out > 0);
     } else if(errno == ERANGE) {
         output = (input[0] != '-');
     } else {
         return false;
     }
     return true;
 }
 
 /// Floats
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::floating_point, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     if(input.empty()) {
         return false;
     }
     char *val = nullptr;
     auto output_ld = std::strtold(input.c_str(), &val);
     output = static_cast<T>(output_ld);
     if(val == (input.c_str() + input.size())) {
         return true;
     }
     // remove separators
     if(input.find_first_of("_'") != std::string::npos) {
         std::string nstring = input;
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '_'), nstring.end());
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '\''), nstring.end());
         return lexical_cast(nstring, output);
     }
     return false;
 }
 
 /// complex
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::complex_number, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     using XC = typename wrapped_type<T, double>::type;
     XC x{0.0}, y{0.0};
     auto str1 = input;
     bool worked = false;
     auto nloc = str1.find_last_of("+-");
     if(nloc != std::string::npos && nloc > 0) {
         worked = lexical_cast(str1.substr(0, nloc), x);
         str1 = str1.substr(nloc);
         if(str1.back() == 'i' || str1.back() == 'j')
             str1.pop_back();
         worked = worked && lexical_cast(str1, y);
     } else {
         if(str1.back() == 'i' || str1.back() == 'j') {
             str1.pop_back();
             worked = lexical_cast(str1, y);
             x = XC{0};
         } else {
             worked = lexical_cast(str1, x);
             y = XC{0};
         }
     }
     if(worked) {
         output = T{x, y};
         return worked;
     }
     return from_stream(input, output);
 }
 
 /// String and similar direct assignment
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::string_assignable, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     output = input;
     return true;
 }
 
 /// String and similar constructible and copy assignment
 template <
     typename T,
     enable_if_t<classify_object<T>::value == object_category::string_constructible, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     output = T(input);
     return true;
 }
 
 /// Wide strings
 template <
     typename T,
     enable_if_t<classify_object<T>::value == object_category::wstring_assignable, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     output = widen(input);
     return true;
 }
 
 template <
     typename T,
     enable_if_t<classify_object<T>::value == object_category::wstring_constructible, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     output = T{widen(input)};
     return true;
 }
 
 /// Enumerations
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::enumeration, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     typename std::underlying_type<T>::type val;
     if(!integral_conversion(input, val)) {
         return false;
     }
     output = static_cast<T>(val);
     return true;
 }
 
 /// wrapper types
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::wrapper_value &&
                           std::is_assignable<T &, typename T::value_type>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     typename T::value_type val;
     if(lexical_cast(input, val)) {
         output = val;
         return true;
     }
     return from_stream(input, output);
 }
 
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::wrapper_value &&
                           !std::is_assignable<T &, typename T::value_type>::value && std::is_assignable<T &, T>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     typename T::value_type val;
     if(lexical_cast(input, val)) {
         output = T{val};
         return true;
     }
     return from_stream(input, output);
 }
 
 /// Assignable from double or int
 template <
     typename T,
     enable_if_t<classify_object<T>::value == object_category::number_constructible, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     int val = 0;
     if(integral_conversion(input, val)) {
         output = T(val);
         return true;
     }
 
     double dval = 0.0;
     if(lexical_cast(input, dval)) {
         output = T{dval};
         return true;
     }
 
     return from_stream(input, output);
 }
 
 /// Assignable from int
 template <
     typename T,
     enable_if_t<classify_object<T>::value == object_category::integer_constructible, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     int val = 0;
     if(integral_conversion(input, val)) {
         output = T(val);
         return true;
     }
     return from_stream(input, output);
 }
 
 /// Assignable from double
 template <
     typename T,
     enable_if_t<classify_object<T>::value == object_category::double_constructible, detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     double val = 0.0;
     if(lexical_cast(input, val)) {
         output = T{val};
         return true;
     }
     return from_stream(input, output);
 }
 
 /// Non-string convertible from an int
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::other && std::is_assignable<T &, int>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     int val = 0;
     if(integral_conversion(input, val)) {
 #ifdef _MSC_VER
 #pragma warning(push)
 #pragma warning(disable : 4800)
 #endif
         // with Atomic<XX> this could produce a warning due to the conversion but if atomic gets here it is an old style
         // so will most likely still work
         output = val;
 #ifdef _MSC_VER
 #pragma warning(pop)
 #endif
         return true;
     }
     // LCOV_EXCL_START
     // This version of cast is only used for odd cases in an older compilers the fail over
     // from_stream is tested elsewhere an not relevant for coverage here
     return from_stream(input, output);
     // LCOV_EXCL_STOP
 }
 
 /// Non-string parsable by a stream
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::other && !std::is_assignable<T &, int>::value &&
                           is_istreamable<T>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string &input, T &output) {
     return from_stream(input, output);
 }
 
 /// Fallback overload that prints a human-readable error for types that we don't recognize and that don't have a
 /// user-supplied lexical_cast overload.
 template <typename T,
           enable_if_t<classify_object<T>::value == object_category::other && !std::is_assignable<T &, int>::value &&
                           !is_istreamable<T>::value && !adl_detail::is_lexical_castable<T>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_cast(const std::string & /*input*/, T & /*output*/) {
     static_assert(!std::is_same<T, T>::value,  // Can't just write false here.
                   "option object type must have a lexical cast overload or streaming input operator(>>) defined, if it "
                   "is convertible from another type use the add_option<T, XC>(...) with XC being the known type");
     return false;
 }
 
 /// Assign a value through lexical cast operations
 /// Strings can be empty so we need to do a little different
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<std::is_same<AssignTo, ConvertTo>::value &&
                           (classify_object<AssignTo>::value == object_category::string_assignable ||
                            classify_object<AssignTo>::value == object_category::string_constructible ||
                            classify_object<AssignTo>::value == object_category::wstring_assignable ||
                            classify_object<AssignTo>::value == object_category::wstring_constructible),
                       detail::enabler> = detail::dummy>
 bool lexical_assign(const std::string &input, AssignTo &output) {
     return lexical_cast(input, output);
 }
 
 /// Assign a value through lexical cast operations
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<std::is_same<AssignTo, ConvertTo>::value && std::is_assignable<AssignTo &, AssignTo>::value &&
                           classify_object<AssignTo>::value != object_category::string_assignable &&
                           classify_object<AssignTo>::value != object_category::string_constructible &&
                           classify_object<AssignTo>::value != object_category::wstring_assignable &&
                           classify_object<AssignTo>::value != object_category::wstring_constructible,
                       detail::enabler> = detail::dummy>
 bool lexical_assign(const std::string &input, AssignTo &output) {
     if(input.empty()) {
         output = AssignTo{};
         return true;
     }
 
     return lexical_cast(input, output);
 }
 
 /// Assign a value through lexical cast operations
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, AssignTo>::value &&
                           classify_object<AssignTo>::value == object_category::wrapper_value,
                       detail::enabler> = detail::dummy>
 bool lexical_assign(const std::string &input, AssignTo &output) {
     if(input.empty()) {
         typename AssignTo::value_type emptyVal{};
         output = emptyVal;
         return true;
     }
     return lexical_cast(input, output);
 }
 
 /// Assign a value through lexical cast operations for int compatible values
 /// mainly for atomic operations on some compilers
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, AssignTo>::value &&
                           classify_object<AssignTo>::value != object_category::wrapper_value &&
                           std::is_assignable<AssignTo &, int>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_assign(const std::string &input, AssignTo &output) {
     if(input.empty()) {
         output = 0;
         return true;
     }
     int val{0};
     if(lexical_cast(input, val)) {
 #if defined(__clang__)
 /* on some older clang compilers */
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wsign-conversion"
 #endif
         output = val;
 #if defined(__clang__)
 #pragma clang diagnostic pop
 #endif
         return true;
     }
     return false;
 }
 
 /// Assign a value converted from a string in lexical cast to the output value directly
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<!std::is_same<AssignTo, ConvertTo>::value && std::is_assignable<AssignTo &, ConvertTo &>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_assign(const std::string &input, AssignTo &output) {
     ConvertTo val{};
     bool parse_result = (!input.empty()) ? lexical_cast(input, val) : true;
     if(parse_result) {
         output = val;
     }
     return parse_result;
 }
 
 /// Assign a value from a lexical cast through constructing a value and move assigning it
 template <
     typename AssignTo,
     typename ConvertTo,
     enable_if_t<!std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, ConvertTo &>::value &&
                     std::is_move_assignable<AssignTo>::value,
                 detail::enabler> = detail::dummy>
 bool lexical_assign(const std::string &input, AssignTo &output) {
     ConvertTo val{};
     bool parse_result = input.empty() ? true : lexical_cast(input, val);
     if(parse_result) {
         output = AssignTo(val);  // use () form of constructor to allow some implicit conversions
     }
     return parse_result;
 }
 
 /// primary lexical conversion operation, 1 string to 1 type of some kind
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<classify_object<ConvertTo>::value <= object_category::other &&
                           classify_object<AssignTo>::value <= object_category::wrapper_value,
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
     return lexical_assign<AssignTo, ConvertTo>(strings[0], output);
 }
 
 /// Lexical conversion if there is only one element but the conversion type is for two, then call a two element
 /// constructor
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<(type_count<AssignTo>::value <= 2) && expected_count<AssignTo>::value == 1 &&
                           is_tuple_like<ConvertTo>::value && type_count_base<ConvertTo>::value == 2,
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
     // the remove const is to handle pair types coming from a container
     using FirstType = typename std::remove_const<typename std::tuple_element<0, ConvertTo>::type>::type;
     using SecondType = typename std::tuple_element<1, ConvertTo>::type;
     FirstType v1;
     SecondType v2;
     bool retval = lexical_assign<FirstType, FirstType>(strings[0], v1);
     retval = retval && lexical_assign<SecondType, SecondType>((strings.size() > 1) ? strings[1] : std::string{}, v2);
     if(retval) {
         output = AssignTo{v1, v2};
     }
     return retval;
 }
 
 /// Lexical conversion of a container types of single elements
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                           type_count<ConvertTo>::value == 1,
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
     output.erase(output.begin(), output.end());
     if(strings.empty()) {
         return true;
     }
     if(strings.size() == 1 && strings[0] == "{}") {
         return true;
     }
     bool skip_remaining = false;
     if(strings.size() == 2 && strings[0] == "{}" && is_separator(strings[1])) {
         skip_remaining = true;
     }
     for(const auto &elem : strings) {
         typename AssignTo::value_type out;
         bool retval = lexical_assign<typename AssignTo::value_type, typename ConvertTo::value_type>(elem, out);
         if(!retval) {
             return false;
         }
         output.insert(output.end(), std::move(out));
         if(skip_remaining) {
             break;
         }
     }
     return (!output.empty());
 }
 
 /// Lexical conversion for complex types
 template <class AssignTo, class ConvertTo, enable_if_t<is_complex<ConvertTo>::value, detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {
 
     if(strings.size() >= 2 && !strings[1].empty()) {
         using XC2 = typename wrapped_type<ConvertTo, double>::type;
         XC2 x{0.0}, y{0.0};
         auto str1 = strings[1];
         if(str1.back() == 'i' || str1.back() == 'j') {
             str1.pop_back();
         }
         auto worked = lexical_cast(strings[0], x) && lexical_cast(str1, y);
         if(worked) {
             output = ConvertTo{x, y};
         }
         return worked;
     }
     return lexical_assign<AssignTo, ConvertTo>(strings[0], output);
 }
 
 /// Conversion to a vector type using a particular single type as the conversion type
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_mutable_container<AssignTo>::value && (expected_count<ConvertTo>::value == 1) &&
                           (type_count<ConvertTo>::value == 1),
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
     bool retval = true;
     output.clear();
     output.reserve(strings.size());
     for(const auto &elem : strings) {
 
         output.emplace_back();
         retval = retval && lexical_assign<typename AssignTo::value_type, ConvertTo>(elem, output.back());
     }
     return (!output.empty()) && retval;
 }
 
 // forward declaration
 
 /// Lexical conversion of a container types with conversion type of two elements
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                           type_count_base<ConvertTo>::value == 2,
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(std::vector<std::string> strings, AssignTo &output);
 
 /// Lexical conversion of a vector types with type_size >2 forward declaration
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                           type_count_base<ConvertTo>::value != 2 &&
                           ((type_count<ConvertTo>::value > 2) ||
                            (type_count<ConvertTo>::value > type_count_base<ConvertTo>::value)),
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output);
 
 /// Conversion for tuples
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_tuple_like<AssignTo>::value && is_tuple_like<ConvertTo>::value &&
                           (type_count_base<ConvertTo>::value != type_count<ConvertTo>::value ||
                            type_count<ConvertTo>::value > 2),
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output);  // forward declaration
 
 /// Conversion for operations where the assigned type is some class but the conversion is a mutable container or large
 /// tuple
 template <typename AssignTo,
           typename ConvertTo,
           enable_if_t<!is_tuple_like<AssignTo>::value && !is_mutable_container<AssignTo>::value &&
                           classify_object<ConvertTo>::value != object_category::wrapper_value &&
                           (is_mutable_container<ConvertTo>::value || type_count<ConvertTo>::value > 2),
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
 
     if(strings.size() > 1 || (!strings.empty() && !(strings.front().empty()))) {
         ConvertTo val;
         auto retval = lexical_conversion<ConvertTo, ConvertTo>(strings, val);
         output = AssignTo{val};
         return retval;
     }
     output = AssignTo{};
     return true;
 }
 
 /// function template for converting tuples if the static Index is greater than the tuple size
 template <class AssignTo, class ConvertTo, std::size_t I>
 inline typename std::enable_if<(I >= type_count_base<AssignTo>::value), bool>::type
 tuple_conversion(const std::vector<std::string> &, AssignTo &) {
     return true;
 }
 
 /// Conversion of a tuple element where the type size ==1 and not a mutable container
 template <class AssignTo, class ConvertTo>
 inline typename std::enable_if<!is_mutable_container<ConvertTo>::value && type_count<ConvertTo>::value == 1, bool>::type
 tuple_type_conversion(std::vector<std::string> &strings, AssignTo &output) {
     auto retval = lexical_assign<AssignTo, ConvertTo>(strings[0], output);
     strings.erase(strings.begin());
     return retval;
 }
 
 /// Conversion of a tuple element where the type size !=1 but the size is fixed and not a mutable container
 template <class AssignTo, class ConvertTo>
 inline typename std::enable_if<!is_mutable_container<ConvertTo>::value && (type_count<ConvertTo>::value > 1) &&
                                    type_count<ConvertTo>::value == type_count_min<ConvertTo>::value,
                                bool>::type
 tuple_type_conversion(std::vector<std::string> &strings, AssignTo &output) {
     auto retval = lexical_conversion<AssignTo, ConvertTo>(strings, output);
     strings.erase(strings.begin(), strings.begin() + type_count<ConvertTo>::value);
     return retval;
 }
 
 /// Conversion of a tuple element where the type is a mutable container or a type with different min and max type sizes
 template <class AssignTo, class ConvertTo>
 inline typename std::enable_if<is_mutable_container<ConvertTo>::value ||
                                    type_count<ConvertTo>::value != type_count_min<ConvertTo>::value,
                                bool>::type
 tuple_type_conversion(std::vector<std::string> &strings, AssignTo &output) {
 
     std::size_t index{subtype_count_min<ConvertTo>::value};
     const std::size_t mx_count{subtype_count<ConvertTo>::value};
     const std::size_t mx{(std::min)(mx_count, strings.size() - 1)};
 
     while(index < mx) {
         if(is_separator(strings[index])) {
             break;
         }
         ++index;
     }
     bool retval = lexical_conversion<AssignTo, ConvertTo>(
         std::vector<std::string>(strings.begin(), strings.begin() + static_cast<std::ptrdiff_t>(index)), output);
     if(strings.size() > index) {
         strings.erase(strings.begin(), strings.begin() + static_cast<std::ptrdiff_t>(index) + 1);
     } else {
         strings.clear();
     }
     return retval;
 }
 
 /// Tuple conversion operation
 template <class AssignTo, class ConvertTo, std::size_t I>
 inline typename std::enable_if<(I < type_count_base<AssignTo>::value), bool>::type
 tuple_conversion(std::vector<std::string> strings, AssignTo &output) {
     bool retval = true;
     using ConvertToElement = typename std::
         conditional<is_tuple_like<ConvertTo>::value, typename std::tuple_element<I, ConvertTo>::type, ConvertTo>::type;
     if(!strings.empty()) {
         retval = retval && tuple_type_conversion<typename std::tuple_element<I, AssignTo>::type, ConvertToElement>(
                                strings, std::get<I>(output));
     }
     retval = retval && tuple_conversion<AssignTo, ConvertTo, I + 1>(std::move(strings), output);
     return retval;
 }
 
 /// Lexical conversion of a container types with tuple elements of size 2
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                           type_count_base<ConvertTo>::value == 2,
                       detail::enabler>>
 bool lexical_conversion(std::vector<std::string> strings, AssignTo &output) {
     output.clear();
     while(!strings.empty()) {
 
         typename std::remove_const<typename std::tuple_element<0, typename ConvertTo::value_type>::type>::type v1;
         typename std::tuple_element<1, typename ConvertTo::value_type>::type v2;
         bool retval = tuple_type_conversion<decltype(v1), decltype(v1)>(strings, v1);
         if(!strings.empty()) {
             retval = retval && tuple_type_conversion<decltype(v2), decltype(v2)>(strings, v2);
         }
         if(retval) {
             output.insert(output.end(), typename AssignTo::value_type{v1, v2});
         } else {
             return false;
         }
     }
     return (!output.empty());
 }
 
 /// lexical conversion of tuples with type count>2 or tuples of types of some element with a type size>=2
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_tuple_like<AssignTo>::value && is_tuple_like<ConvertTo>::value &&
                           (type_count_base<ConvertTo>::value != type_count<ConvertTo>::value ||
                            type_count<ConvertTo>::value > 2),
                       detail::enabler>>
 bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
     static_assert(
         !is_tuple_like<ConvertTo>::value || type_count_base<AssignTo>::value == type_count_base<ConvertTo>::value,
         "if the conversion type is defined as a tuple it must be the same size as the type you are converting to");
     return tuple_conversion<AssignTo, ConvertTo, 0>(strings, output);
 }
 
 /// Lexical conversion of a vector types for everything but tuples of two elements and types of size 1
 template <class AssignTo,
           class ConvertTo,
           enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                           type_count_base<ConvertTo>::value != 2 &&
                           ((type_count<ConvertTo>::value > 2) ||
                            (type_count<ConvertTo>::value > type_count_base<ConvertTo>::value)),
                       detail::enabler>>
 bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
     bool retval = true;
     output.clear();
     std::vector<std::string> temp;
     std::size_t ii{0};
     std::size_t icount{0};
     std::size_t xcm{type_count<ConvertTo>::value};
     auto ii_max = strings.size();
     while(ii < ii_max) {
         temp.push_back(strings[ii]);
         ++ii;
         ++icount;
         if(icount == xcm || is_separator(temp.back()) || ii == ii_max) {
             if(static_cast<int>(xcm) > type_count_min<ConvertTo>::value && is_separator(temp.back())) {
                 temp.pop_back();
             }
             typename AssignTo::value_type temp_out;
             retval = retval &&
                      lexical_conversion<typename AssignTo::value_type, typename ConvertTo::value_type>(temp, temp_out);
             temp.clear();
             if(!retval) {
                 return false;
             }
             output.insert(output.end(), std::move(temp_out));
             icount = 0;
         }
     }
     return retval;
 }
 
 /// conversion for wrapper types
 template <typename AssignTo,
           class ConvertTo,
           enable_if_t<classify_object<ConvertTo>::value == object_category::wrapper_value &&
                           std::is_assignable<ConvertTo &, ConvertTo>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {
     if(strings.empty() || strings.front().empty()) {
         output = ConvertTo{};
         return true;
     }
     typename ConvertTo::value_type val;
     if(lexical_conversion<typename ConvertTo::value_type, typename ConvertTo::value_type>(strings, val)) {
         output = ConvertTo{val};
         return true;
     }
     return false;
 }
 
 /// conversion for wrapper types
 template <typename AssignTo,
           class ConvertTo,
           enable_if_t<classify_object<ConvertTo>::value == object_category::wrapper_value &&
                           !std::is_assignable<AssignTo &, ConvertTo>::value,
                       detail::enabler> = detail::dummy>
 bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {
     using ConvertType = typename ConvertTo::value_type;
     if(strings.empty() || strings.front().empty()) {
         output = ConvertType{};
         return true;
     }
     ConvertType val;
     if(lexical_conversion<typename ConvertTo::value_type, typename ConvertTo::value_type>(strings, val)) {
         output = val;
         return true;
     }
     return false;
 }
 
 /// Sum a vector of strings
 inline std::string sum_string_vector(const std::vector<std::string> &values) {
     double val{0.0};
     bool fail{false};
     std::string output;
     for(const auto &arg : values) {
         double tv{0.0};
         auto comp = lexical_cast(arg, tv);
         if(!comp) {
             errno = 0;
             auto fv = detail::to_flag_value(arg);
             fail = (errno != 0);
             if(fail) {
                 break;
             }
             tv = static_cast<double>(fv);
         }
         val += tv;
     }
     if(fail) {
         for(const auto &arg : values) {
             output.append(arg);
         }
     } else {
         std::ostringstream out;
         out.precision(16);
         out << val;
         output = out.str();
     }
     return output;
 }
 
 }  // namespace detail
 // [CLI11:type_tools_hpp:end]
 }  // namespace CLI

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