Provide GncOption::GetLimits for setting a NUMBER_RANGE spin button.

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

@@ -400,6 +400,12 @@ public:
         else
             throw std::invalid_argument("Validation failed, value not set.");
     }
+    void get_limits(ValueType& upper, ValueType& lower, ValueType& step) const noexcept
+    {
+        upper = m_max;
+        lower = m_min;
+        step = m_step;
+    }
     bool is_changed() const noexcept { return m_value != m_default_value; }
     GncOptionUIType get_ui_type() const noexcept { return m_ui_type; }
     void make_internal() { m_ui_type = GncOptionUIType::INTERNAL; }

libgnucash/app-utils/gnc-option.cpp

@@ -123,6 +123,17 @@ GncOption::set_value(ValueType value)
                }, *m_option);
 }
 
+template <typename ValueType> void
+GncOption::get_limits(ValueType& max, ValueType& min, ValueType& step) const noexcept
+{
+    std::visit([&max, &min, &step](const auto& option) {
+                   if constexpr
+                       (std::is_same_v<std::decay_t<decltype(option)>,
+                        GncOptionRangeValue<ValueType>>)
+                       option.get_limits(max, min, step);
+               }, *m_option);
+}
+
 const std::string&
 GncOption::get_section() const
 {
@@ -478,6 +489,8 @@ template void GncOption::set_value(RelativeDatePeriod);
 template void GncOption::set_value(size_t);
 template void GncOption::set_value(GncMultichoiceOptionIndexVec);
 
+template void GncOption::get_limits(double&, double&, double&) const noexcept;
+template void GncOption::get_limits(int&, int&, int&) const noexcept;
 template bool GncOption::validate(bool) const;
 template bool GncOption::validate(int) const;
 template bool GncOption::validate(int64_t) const;

libgnucash/app-utils/gnc-option.hpp

@@ -87,6 +87,8 @@ public:
     void make_internal();
     bool is_changed() const noexcept;
     bool is_multiselect() const noexcept;
+    template <typename ValueType> void get_limits(ValueType&, ValueType&,
+                                                  ValueType&) const noexcept;
     template <typename ValueType> bool validate(ValueType value) const;
     std::size_t num_permissible_values() const;
     std::size_t permissible_value_index(const char* value) const;

libgnucash/app-utils/test/gtest-gnc-option.cpp

@@ -622,6 +622,20 @@ TEST_F(GncRangeOption, test_setter)
     EXPECT_EQ(1.5, m_doubleoption.get_default_value<double>());
 }
 
+TEST_F(GncRangeOption, test_get_info)
+{
+    int imax{}, imin{}, istep{};
+    double dmax{}, dmin{}, dstep{};
+    m_intoption.get_limits(imax, imin, istep);
+    m_doubleoption.get_limits(dmax, dmin, dstep);
+    EXPECT_EQ(30, imax);
+    EXPECT_EQ(1, imin);
+    EXPECT_EQ(1, istep);
+    EXPECT_EQ(1.0, dmin);
+    EXPECT_EQ(3.0, dmax);
+    EXPECT_EQ(0.1, dstep);
+}
+
 TEST_F(GncRangeOption, test_range_out)
 {
     std::ostringstream oss;