Added templated constructor to C++11 Approx

When using C++11, comparison operators are already templated to take
anything that can be explicitly converted to double, but constructor
took only doubles. This lead to warnings when an `Approx` was
constructed from floats, which was problematic for some users.

Since just adding float constructor would be a large breaking change, as
suddenly `Approx( 1 )` would become ambiguous, I added a templated
constructor that will take anything that is explicitly convertible to
double. This has the added benefit of allowing constructing `Approx`
instances from instances of strong typedefs, ie allowing
`calculated_temp == Approx( known_temp)`.

Closes #873
This commit is contained in:
Martin Hořeňovský 2017-04-04 15:19:15 +02:00
parent cdd83c2e15
commit 0354d50278

View File

@ -49,6 +49,12 @@ namespace Detail {
} }
#if defined(CATCH_CONFIG_CPP11_TYPE_TRAITS) #if defined(CATCH_CONFIG_CPP11_TYPE_TRAITS)
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
explicit Approx( T value ): Approx(static_cast<double>(value))
{}
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type> template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator == ( const T& lhs, Approx const& rhs ) { friend bool operator == ( const T& lhs, Approx const& rhs ) {
// Thanks to Richard Harris for his help refining this formula // Thanks to Richard Harris for his help refining this formula
@ -76,26 +82,22 @@ namespace Detail {
} }
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type> template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator <= ( T lhs, Approx const& rhs ) friend bool operator <= ( T lhs, Approx const& rhs ) {
{
return double(lhs) < rhs.m_value || lhs == rhs; return double(lhs) < rhs.m_value || lhs == rhs;
} }
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type> template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator <= ( Approx const& lhs, T rhs ) friend bool operator <= ( Approx const& lhs, T rhs ) {
{
return lhs.m_value < double(rhs) || lhs == rhs; return lhs.m_value < double(rhs) || lhs == rhs;
} }
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type> template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator >= ( T lhs, Approx const& rhs ) friend bool operator >= ( T lhs, Approx const& rhs ) {
{
return double(lhs) > rhs.m_value || lhs == rhs; return double(lhs) > rhs.m_value || lhs == rhs;
} }
template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type> template <typename T, typename = typename std::enable_if<std::is_constructible<double, T>::value>::type>
friend bool operator >= ( Approx const& lhs, T rhs ) friend bool operator >= ( Approx const& lhs, T rhs ) {
{
return lhs.m_value > double(rhs) || lhs == rhs; return lhs.m_value > double(rhs) || lhs == rhs;
} }
#else #else
@ -120,23 +122,19 @@ namespace Detail {
return !operator==( rhs, lhs ); return !operator==( rhs, lhs );
} }
friend bool operator <= ( double lhs, Approx const& rhs ) friend bool operator <= ( double lhs, Approx const& rhs ) {
{
return lhs < rhs.m_value || lhs == rhs; return lhs < rhs.m_value || lhs == rhs;
} }
friend bool operator <= ( Approx const& lhs, double rhs ) friend bool operator <= ( Approx const& lhs, double rhs ) {
{
return lhs.m_value < rhs || lhs == rhs; return lhs.m_value < rhs || lhs == rhs;
} }
friend bool operator >= ( double lhs, Approx const& rhs ) friend bool operator >= ( double lhs, Approx const& rhs ) {
{
return lhs > rhs.m_value || lhs == rhs; return lhs > rhs.m_value || lhs == rhs;
} }
friend bool operator >= ( Approx const& lhs, double rhs ) friend bool operator >= ( Approx const& lhs, double rhs ) {
{
return lhs.m_value > rhs || lhs == rhs; return lhs.m_value > rhs || lhs == rhs;
} }
#endif #endif