Hi,
While making myself an interim shared_resource class, I found myself reusing
the shared_ptr safe-bool conversion, and thought that really the idiom ought
to go into the operators library.
I am unsure about the name, but for now bool_testable seems to match the
naming style used by the rest of operators, and be reasonably clear about
its intent. Any suggestions gratefully received
Essentially you supply a operator! and it supplies an unspecified-bool-type
conversion operator.
//Key
//T: primary operand type
//t: values of type T
// Template Supplied Operations Requirements
//
// bool_testable<T> operator unspecified-bool-type() !t
template <class T, class B = ::boost::detail::empty_base> struct
bool_testable : B
{
private:
void safe_bool_conversion() const { }
public:
typedef void (bool_testable<T, B>::*unspecified_bool_type)() const;
operator unspecified_bool_type() const
{
return !static_cast<const T&>(*this) ? 0 : &bool_testable<T,
B>::safe_bool_conversion;
}
};
Any problems with this?
Sam
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