Improve template conditional readability with custom traits values.

libgnucash/app-utils/gnc-option-impl.hpp

@@ -237,6 +237,18 @@ QofInstance* qof_instance_from_string(const std::string& str,
 QofInstance* qof_instance_from_guid(GncGUID*, GncOptionUIType type);
 std::string qof_instance_to_string(const QofInstance* inst);
 
+template <typename T>
+struct is_QofInstanceValue
+{
+    static constexpr bool value =
+         (std::is_same_v<std::decay_t<T>, GncOptionValue<const QofInstance*>> ||
+          std::is_same_v<std::decay_t<T>,
+          GncOptionValidatedValue<const QofInstance*>>);
+};
+
+template <typename T> inline constexpr bool
+is_QofInstanceValue_v = is_QofInstanceValue<T>::value;
+
 /* These will work when m_value is a built-in class; GnuCash class and container
  * values will need specialization unless they happen to define operators << and
  * >>.
@@ -246,16 +258,9 @@ std::string qof_instance_to_string(const QofInstance* inst);
  */
 #ifndef SWIG
 template<class OptType,
-         typename std::enable_if_t<std::is_base_of_v<OptionClassifier,
-                                                     std::decay_t<OptType>> &&
-                                   ! (std::is_same_v<std::decay_t<OptType>,
-                                      GncOptionValue<const QofInstance*>> ||
-                                      std::is_same_v<std::decay_t<OptType>,
-                                      GncOptionValidatedValue<const QofInstance*>> ||
-                                      std::is_same_v<std::decay_t<OptType>,
-                                      GncOptionRangeValue<int>> ||
-                                      std::is_same_v<std::decay_t<OptType>,
-                                      GncOptionRangeValue<double>>), int> = 0>
+         typename std::enable_if_t<is_OptionClassifier_v<OptType> &&
+                                   ! (is_QofInstanceValue_v<OptType> ||
+                                      is_RangeValue_v<OptType>), int> = 0>
 std::ostream& operator<<(std::ostream& oss, const OptType& opt)
 {
     oss << opt.get_value();
@@ -271,10 +276,7 @@ operator<< <GncOptionValue<bool>>(std::ostream& oss,
 }
 
 template<class OptType,
-         typename std::enable_if_t<std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionValidatedValue<const QofInstance*>> ||
-                                   std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionValue<const QofInstance*> >, int> = 0>
+         typename std::enable_if_t<is_QofInstanceValue_v<OptType>, int> = 0>
 inline std::ostream&
 operator<< (std::ostream& oss, const OptType& opt)
 {
@@ -296,16 +298,9 @@ operator<< (std::ostream& oss, const OptType& opt)
 }
 
 template<class OptType,
-         typename std::enable_if_t<std::is_base_of_v<OptionClassifier,
-                                                     std::decay_t<OptType>> &&
-                                   !(std::is_same_v<std::decay_t<OptType>,
-                                     GncOptionValue<const QofInstance*>> ||
-                                     std::is_same_v<std::decay_t<OptType>,
-                                     GncOptionValidatedValue<const QofInstance*>> ||
-                                      std::is_same_v<std::decay_t<OptType>,
-                                      GncOptionRangeValue<int>> ||
-                                      std::is_same_v<std::decay_t<OptType>,
-                                      GncOptionRangeValue<double>>), int> = 0>
+         typename std::enable_if_t<is_OptionClassifier_v<OptType> &&
+                                   !(is_QofInstanceValue_v<OptType> ||
+                                     is_RangeValue_v<OptType>), int> = 0>
 std::istream& operator>>(std::istream& iss, OptType& opt)
 {
     std::decay_t<decltype(opt.get_value())> value;
@@ -322,11 +317,7 @@ std::istream& operator>>(std::istream& iss, OptType& opt)
 }
 
 template<class OptType,
-         typename std::enable_if_t<std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionValidatedValue<const QofInstance*>> ||
-                                   std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionValue<const QofInstance*> >,
-                                   int> = 0>
+         typename std::enable_if_t<is_QofInstanceValue_v<OptType>, int> = 0>
 std::istream&
 operator>> (std::istream& iss, OptType& opt)
 {
@@ -507,11 +498,7 @@ private:
 };
 
 template<class OptType,
-         typename std::enable_if_t<std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionRangeValue<int>> ||
-                                   std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionRangeValue<double>>,
-                                   int> = 0>
+         typename std::enable_if_t<is_RangeValue_v<OptType>, int> = 0>
 inline std::ostream&
 operator<< (std::ostream& oss, const OptType& opt)
 {
@@ -522,11 +509,7 @@ operator<< (std::ostream& oss, const OptType& opt)
 }
 
 template<class OptType,
-         typename std::enable_if_t<std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionRangeValue<int>> ||
-                                   std::is_same_v<std::decay_t<OptType>,
-                                                  GncOptionRangeValue<double>>,
-                                   int> = 0>
+         typename std::enable_if_t<is_RangeValue_v<OptType>, int> = 0>
 inline std::istream&
 operator>> (std::istream& iss, OptType& opt)
 {

libgnucash/app-utils/gnc-option.cpp

@@ -34,8 +34,7 @@ extern "C"
 }
 
 template <typename ValueType,
-          typename std::enable_if_t<!std::is_base_of_v<OptionClassifier,
-                                                       std::decay_t<ValueType>>,
+          typename std::enable_if_t<!is_OptionClassifier_v<ValueType>,
                                int>>
 GncOption::GncOption(const char* section, const char* name,
                      const char* key, const char* doc_string,
@@ -49,31 +48,30 @@ GncOption::GncOption(const char* section, const char* name,
 template <typename ValueType> ValueType
 GncOption::get_value() const
 {
-    return std::visit([](const auto option)->ValueType {
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option.get_value())>, std::decay_t<ValueType>>)
+    return std::visit(
+        [](const auto option)->ValueType {
+            if constexpr (is_same_decayed_v<decltype(option.get_value()),
+                          ValueType>)
                                            return option.get_value();
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                                        GncOptionDateValue> &&
-                                        std::is_same_v<std::decay_t<ValueType>,
+            if constexpr (is_same_decayed_v<decltype(option),
+                          GncOptionDateValue>)
+            {
+                if constexpr (is_same_decayed_v<ValueType,
                                         RelativeDatePeriod>)
                               return option.get_period();
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                                        GncOptionDateValue> &&
-                                        std::is_same_v<std::decay_t<ValueType>,
-                                        size_t>)
+                if constexpr (std::is_same_v<ValueType, size_t>)
                               return option.get_period_index();
-                          if constexpr
-                              (std::is_same_v<std::decay_t<decltype(option)>,
-                               GncOptionMultichoiceValue> &&
-                               std::is_same_v<std::decay_t<ValueType>,
-                               size_t>)
+                return ValueType{};
+            }
+            if constexpr (is_same_decayed_v<decltype(option),
+                          GncOptionMultichoiceValue>)
+            {
+                if constexpr (std::is_same_v<ValueType, size_t>)
                               return option.get_index();
-                          if constexpr
-                              (std::is_same_v<std::decay_t<decltype(option)>,
-                               GncOptionMultichoiceValue> &&
-                               std::is_same_v<std::decay_t<ValueType>,
+                if constexpr (is_same_decayed_v<ValueType,
                                GncMultichoiceOptionIndexVec>)
                               return option.get_multiple();
+            }
                           return ValueType {};
                       }, *m_option);
 }
@@ -81,23 +79,25 @@ GncOption::get_value() const
 template <typename ValueType> ValueType
 GncOption::get_default_value() const
 {
-    return std::visit([](const auto option)->ValueType {
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option.get_value())>, std::decay_t<ValueType>>)
+    return std::visit(
+        [](const auto option)->ValueType {
+            if constexpr (is_same_decayed_v<decltype(option.get_value()),
+                          ValueType>)
                                            return option.get_default_value();
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                                        GncOptionDateValue> &&
-                                        std::is_same_v<std::decay_t<ValueType>,
+            if constexpr (is_same_decayed_v<decltype(option),
+                          GncOptionDateValue>)
+            {
+                if constexpr (is_same_decayed_v<ValueType,
                                         RelativeDatePeriod>)
                               return option.get_default_period();
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                                        GncOptionDateValue> &&
-                                        std::is_same_v<std::decay_t<ValueType>,
-                                        size_t>)
+                if constexpr (std::is_same_v<ValueType, size_t>)
                               return option.get_default_period_index();
+                return ValueType{};
+            }
                           if constexpr
-                              (std::is_same_v<std::decay_t<decltype(option)>,
+                (is_same_decayed_v<decltype(option),
                                GncOptionMultichoiceValue> &&
-                               std::is_same_v<std::decay_t<ValueType>,
+                 is_same_decayed_v<ValueType,
                                GncMultichoiceOptionIndexVec>)
                               return option.get_default_multiple();
                           return ValueType {};
@@ -108,26 +108,24 @@ GncOption::get_default_value() const
 template <typename ValueType> void
 GncOption::set_value(ValueType value)
 {
-    std::visit([value](auto& option) {
+    std::visit(
+        [value](auto& option) {
                    if constexpr
-                       (std::is_same_v<std::decay_t<decltype(option.get_value())>,
-                        std::decay_t<ValueType>> ||
-                        (std::is_same_v<std::decay_t<decltype(option)>,
+                (is_same_decayed_v<decltype(option.get_value()), ValueType> ||
+                 (is_same_decayed_v<decltype(option),
                          GncOptionDateValue> &&
-                         (std::is_same_v<std::decay_t<ValueType>,
-                         RelativeDatePeriod> ||
-                          std::is_same_v<std::decay_t<ValueType>, size_t>)))
+                  (is_same_decayed_v<ValueType, RelativeDatePeriod> ||
+                   std::is_same_v<ValueType, size_t>)))
                        option.set_value(value);
-                   if constexpr
-                       (std::is_same_v<std::decay_t<decltype(option)>,
+            if constexpr (is_same_decayed_v<decltype(option),
                         GncOptionMultichoiceValue>)
                    {
-                       if constexpr (std::is_same_v<std::decay_t<ValueType>,
+                if constexpr (is_same_decayed_v<ValueType,
                                      GncMultichoiceOptionIndexVec>)
                            option.set_multiple(value);
                        else if constexpr
                            (std::is_same_v<ValueType, size_t> ||
-                            std::is_same_v<std::decay_t<ValueType>, std::string> ||
+                     is_same_decayed_v<ValueType, std::string> ||
                             std::is_same_v<std::remove_cv<ValueType>, char*>)
                            option.set_value(value);
                    }
@@ -137,27 +135,23 @@ GncOption::set_value(ValueType value)
 template <typename ValueType> void
 GncOption::set_default_value(ValueType value)
 {
-    std::visit([value](auto& option) {
+    std::visit(
+        [value](auto& option) {
                    if constexpr
-                       (std::is_same_v<std::decay_t<decltype(option.get_value())>,
-                        std::decay_t<ValueType>> ||
-                        (std::is_same_v<std::decay_t<decltype(option)>,
-                         GncOptionDateValue> &&
-                         (std::is_same_v<std::decay_t<ValueType>,
-                         RelativeDatePeriod> ||
-                          std::is_same_v<std::decay_t<ValueType>, size_t>)))
+                (is_same_decayed_v<decltype(option.get_value()), ValueType>||
+                 (is_same_decayed_v<decltype(option), GncOptionDateValue> &&
+                  (is_same_decayed_v<ValueType, RelativeDatePeriod> ||
+                   std::is_same_v<ValueType, size_t>)))
                        option.set_default_value(value);
-                   if constexpr
-                       (std::is_same_v<std::decay_t<decltype(option)>,
+            if constexpr (is_same_decayed_v<decltype(option),
                         GncOptionMultichoiceValue>)
                    {
-                       if constexpr
-                           (std::is_same_v<std::decay_t<ValueType>,
+                if constexpr (is_same_decayed_v<ValueType,
                             GncMultichoiceOptionIndexVec>)
-                           option.set_multiple(value);
+                    option.set_default_multiple(value);
                        else if constexpr
                            (std::is_same_v<ValueType, size_t> ||
-                            std::is_same_v<std::decay_t<ValueType>, std::string> ||
+                     is_same_decayed_v<ValueType, std::string> ||
                             std::is_same_v<std::remove_cv<ValueType>, char*>)
                            option.set_default_value(value);
                    }
@@ -174,7 +168,7 @@ GncOption::get_limits(ValueType& max, ValueType& min, ValueType& step) const noe
 {
     std::visit([&max, &min, &step](const auto& option) {
                    if constexpr
-                       (std::is_same_v<std::decay_t<decltype(option)>,
+                       (is_same_decayed_v<decltype(option),
                         GncOptionRangeValue<ValueType>>)
                        option.get_limits(max, min, step);
                }, *m_option);
@@ -292,8 +286,9 @@ GncOption::is_changed() const noexcept
 bool
 GncOption::is_multiselect() const noexcept
 {
-    return std::visit([](const auto& option)->bool {
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+    return std::visit(
+        [](const auto& option)->bool {
+            if constexpr (is_same_decayed_v<decltype(option),
                                         GncOptionAccountListValue>)
                               return option.is_multiselect();
                           else
@@ -304,16 +299,17 @@ GncOption::is_multiselect() const noexcept
 template<typename ValueType> bool
 GncOption::validate(ValueType value) const
 {
-    return std::visit([value] (const auto& option) -> bool {
-                          if constexpr ((std::is_same_v<std::decay_t<decltype(option)>,
+    return std::visit(
+        [value] (const auto& option) -> bool {
+            if constexpr ((is_same_decayed_v<decltype(option),
                                          GncOptionMultichoiceValue> &&
-                                         std::is_same_v<std::decay_t<ValueType>,
+                           is_same_decayed_v<ValueType,
                                          std::string>) ||
-                                        (std::is_same_v<std::decay_t<decltype(option)>,
+                          (is_same_decayed_v<decltype(option),
                                          GncOptionMultichoiceValue> &&
-                                         std::is_same_v<std::decay_t<ValueType>,
+                           is_same_decayed_v<ValueType,
                                          GncMultichoiceOptionIndexVec>) ||
-                                        std::is_same_v<std::decay_t<decltype(option)>,
+                          is_same_decayed_v<decltype(option),
                                         GncOptionValidatedValue<ValueType>>)
                                            return option.validate(value);
                           else
@@ -324,10 +320,11 @@ GncOption::validate(ValueType value) const
 std::size_t
 GncOption::num_permissible_values() const
 {
-    return std::visit([] (const auto& option) -> size_t {
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+    return std::visit(
+        [] (const auto& option) -> size_t {
+            if constexpr (is_same_decayed_v<decltype(option),
                                         GncOptionMultichoiceValue>  ||
-                                        std::is_same_v<std::decay_t<decltype(option)>,
+                          is_same_decayed_v<decltype(option),
                                         GncOptionDateValue>)
                                            return option.num_permissible_values();
                           else
@@ -338,10 +335,11 @@ GncOption::num_permissible_values() const
 std::size_t
 GncOption::permissible_value_index(const char* value) const
 {
-    return std::visit([&value] (const auto& option) -> size_t {
-                          if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+    return std::visit(
+        [&value] (const auto& option) -> size_t {
+            if constexpr (is_same_decayed_v<decltype(option),
                                         GncOptionMultichoiceValue>  ||
-                                        std::is_same_v<std::decay_t<decltype(option)>,
+                          is_same_decayed_v<decltype(option),
                                         GncOptionDateValue>)
                                            return option.permissible_value_index(value);
                           else
@@ -393,10 +391,7 @@ bool
 GncOption::is_alternate() const noexcept
 {
     return std::visit([](auto& option) -> bool {
-                          if constexpr(std::is_same_v<std::decay_t<decltype(option)>,
-                                       GncOptionRangeValue<int>> ||
-                       std::is_same_v<std::decay_t<decltype(option)>,
-                                       GncOptionRangeValue<double>>)
+                          if constexpr(is_RangeValue_v<decltype(option)>)
                               return option.is_alternate();
                           return false;
                       }, *m_option);
@@ -406,10 +401,7 @@ void
 GncOption::set_alternate(bool alt) noexcept
 {
     std::visit([alt](auto& option) {
-                   if constexpr(std::is_same_v<std::decay_t<decltype(option)>,
-                                GncOptionRangeValue<int>> ||
-                       std::is_same_v<std::decay_t<decltype(option)>,
-                                GncOptionRangeValue<double>>)
+                   if constexpr(is_RangeValue_v<decltype(option)>)
                        option.set_alternate(alt);
                }, *m_option);
 }

libgnucash/app-utils/gnc-option.hpp

@@ -53,6 +53,38 @@ template <typename ValueType> class GncOptionRangeValue;
 template <typename ValueType> class GncOptionValidatedValue;
 class GncOptionDateValue;
 
+template <typename T>
+struct is_OptionClassifier
+{
+    static constexpr bool value =
+        std::is_base_of_v<OptionClassifier, std::decay_t<T>>;
+};
+
+template <typename T> inline constexpr bool
+is_OptionClassifier_v = is_OptionClassifier<T>::value;
+
+template <typename T, typename U>
+struct is_same_decayed
+{
+    static constexpr bool value = std::is_same_v<std::decay_t<T>,
+                                                 std::decay_t<U>>;
+};
+
+template <typename T, typename U> inline constexpr bool
+is_same_decayed_v = is_same_decayed<T, U>::value;
+
+template <typename T>
+struct is_RangeValue
+{
+    static constexpr bool value =
+         (is_same_decayed_v<T, GncOptionRangeValue<int>> ||
+          is_same_decayed_v<T, GncOptionRangeValue<double>>);
+};
+
+template <typename T> inline constexpr bool
+is_RangeValue_v = is_RangeValue<T>::value;
+
+
 using GncOptionVariant = std::variant<GncOptionValue<std::string>,
                                       GncOptionValue<bool>,
                                       GncOptionValue<int64_t>,
@@ -82,14 +114,13 @@ class GncOption
 {
 public:
     template <typename OptionType,
-              typename std::enable_if_t<std::is_base_of_v<OptionClassifier,
-                                                          std::decay_t<OptionType>>,
+              typename std::enable_if_t<is_OptionClassifier_v<OptionType>,
                                int>  = 0>
+
     GncOption(OptionType option) :
         m_option{std::make_unique<GncOptionVariant>(option)} {}
     template <typename ValueType,
-              typename std::enable_if_t<!std::is_base_of_v<OptionClassifier,
-                                                          std::decay_t<ValueType>>,
+              typename std::enable_if_t<!is_OptionClassifier_v<ValueType>,
                                int>  = 0>
     GncOption(const char* section, const char* name,
               const char* key, const char* doc_string,

libgnucash/app-utils/gnc-optiondb.i

@@ -263,7 +263,7 @@ scm_color_list_to_string(SCM list)
 template <typename ValueType> inline ValueType
 scm_to_value(SCM new_value)
 {
-    if constexpr (std::is_same_v<std::decay_t<ValueType>, SCM>)
+    if constexpr (is_same_decayed_v<ValueType, SCM>)
         return new_value;
     return ValueType{};
 }
@@ -816,7 +816,26 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
         return scm_cons(desig, scm_from_int(val));
     }
 
-    %}
+template <typename T>
+struct is_MultichoiceOrRange
+{
+    static constexpr bool value =
+        is_same_decayed_v<T, GncOptionMultichoiceValue> ||
+        is_same_decayed_v<T, GncOptionRangeValue<int>>;
+};
+
+template <typename T>
+inline constexpr bool is_MultichoiceOrRange_v = is_MultichoiceOrRange<T>::value;
+
+template <typename ValueType>
+inline SCM return_scm_value(ValueType value)
+{
+    if constexpr (is_same_decayed_v<ValueType, SCM>)
+        return value;
+    return scm_from_value(static_cast<ValueType>(value));
+}
+
+%}
 %ignore GncOptionDBCallback;
 
 %include "gnc-option-date.hpp"
@@ -840,16 +859,10 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
         if (!$self)
             return SCM_BOOL_F;
         return std::visit([](const auto& option)->SCM {
-                if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                              GncOptionMultichoiceValue> ||
-                              std::is_same_v<std::decay_t<decltype(option)>,
-                              GncOptionRangeValue<int>>)
+                if constexpr (is_MultichoiceOrRange_v<decltype(option)>)
                     return get_scm_value(option);
                 auto value{option.get_value()};
-                if constexpr (std::is_same_v<std::decay_t<decltype(value)>,
-                              SCM>)
-                    return value;
-                return scm_from_value(static_cast<decltype(value)>(value));
+                return return_scm_value(value);
             }, swig_get_option($self));
     }
     SCM get_scm_default_value()
@@ -857,25 +870,20 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
         if (!$self)
             return SCM_BOOL_F;
         return std::visit([](const auto& option)->SCM {
-                if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                              GncOptionMultichoiceValue> ||
-                              std::is_same_v<std::decay_t<decltype(option)>,
-                              GncOptionRangeValue<int>>)
+                if constexpr (is_MultichoiceOrRange_v<decltype(option)>)
                     return get_scm_default_value(option);
                 auto value{option.get_default_value()};
-                if constexpr (std::is_same_v<std::decay_t<decltype(value)>,
-                              SCM>)
-                    return value;
-                return scm_from_value(static_cast<decltype(value)>(value));
+                return return_scm_value(value);
             }, swig_get_option($self));
     }
+
     void set_value_from_scm(SCM new_value)
     {
         if (!$self)
             return;
         try {
             std::visit([new_value](auto& option) {
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+                    if constexpr (is_same_decayed_v<decltype(option),
                                   GncOptionDateValue>)
                     {
                         if (scm_date_absolute(new_value))
@@ -885,14 +893,14 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
                         return;
                     }
 
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+                    if constexpr (is_same_decayed_v<decltype(option),
                                   GncOptionMultichoiceValue>)
                     {
                         option.set_multiple(scm_to_multichoices(new_value, option));
                         return;
                     }
 
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+                    if constexpr (is_same_decayed_v<decltype(option),
                                   GncOptionRangeValue<int>>)
                     {
                         if (scm_is_pair(new_value))
@@ -901,10 +909,7 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
                             option.set_value(scm_to_int(new_value));
                         return;
                     }
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                                  GncOptionValue<const QofInstance*>> ||
-                                  std::is_same_v<std::decay_t<decltype(option)>,
-                                  GncOptionValidatedValue<const QofInstance*>>)
+                    if constexpr (is_QofInstanceValue_v<decltype(option)>)
                     {
                         if (scm_is_string(new_value))
                         {
@@ -937,7 +942,7 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
             return;
         try {
             std::visit([new_value](auto& option) {
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+                    if constexpr (is_same_decayed_v<decltype(option),
                                   GncOptionDateValue>)
                     {
                         if (scm_date_absolute(new_value))
@@ -946,14 +951,14 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
                             option.set_default_value(scm_relative_date_get_period(new_value));
                         return;
                     }
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+                    if constexpr (is_same_decayed_v<decltype(option),
                                   GncOptionMultichoiceValue>)
                     {
                         option.set_default_multiple(scm_to_multichoices(new_value,
                                                                         option));
                         return;
                     }
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
+                    if constexpr (is_same_decayed_v<decltype(option),
                                   GncOptionRangeValue<int>>)
                     {
                         if (scm_is_pair(new_value))
@@ -962,10 +967,7 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
                             option.set_default_value(scm_to_int(new_value));
                         return;
                     }
-                    if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                                  GncOptionValue<const QofInstance*>> ||
-                                  std::is_same_v<std::decay_t<decltype(option)>,
-                                  GncOptionValidatedValue<const QofInstance*>>)
+                    if constexpr (is_QofInstanceValue_v<decltype(option)>)
                     {
                         if (scm_is_string(new_value))
                         {
@@ -996,11 +998,11 @@ wrap_unique_ptr(GncOptionDBPtr, GncOptionDB);
         if (!self)
             return SCM_BOOL_F;
         return std::visit([](const auto& option)->SCM {
-                if constexpr (std::is_same_v<std::decay_t<decltype(option)>,
-                    GncOptionMultichoiceValue>)
+                if constexpr (is_same_decayed_v<decltype(option),
+                              GncOptionMultichoiceValue>)
                     return scm_c_eval_string("'multichoice");
                 else if constexpr (std::is_same_v<decltype(option.get_value()),
-                    bool>)
+                                   bool>)
                     return scm_c_eval_string("'boolean");
                 else
                     return SCM_BOOL_F;