2011/3/18 Frédéric Bron <frederic.bron@m4x.org>:
I've found some problems. In the ICL I have an operator +
template <class Type> inline typename enable_if <is_associative_element_container<Type>, Type>::type operator + (Type object, const Type& operand);
and is seems that more overloads are checked valid as actually exist. Is this intentional?
BOOST_AUTO_TEST_CASE(has_op_extension_qualifiers) { typedef int T; typedef interval_set<T> IntervalSetT; typedef IntervalSetT::interval_type IntervalT;
// This is supposed to succeed BOOST_CHECK((has_operator_plus<IntervalSetT, const IntervalSetT&, IntervalSetT>::value));
BOOST_CHECK((!is_convertible<const IntervalSetT&, IntervalSetT&>::value));
// These are supposed to fail, but they succeed BOOST_CHECK((has_operator_plus<IntervalSetT, IntervalSetT&, IntervalSetT>::value)); BOOST_CHECK((has_operator_plus<IntervalSetT, IntervalSetT, IntervalSetT>::value)); BOOST_CHECK((has_operator_plus<IntervalSetT, IntervalSetT, IntervalSetT const&>::value)); }
Your question here is the same as the following example:
struct T { }; struct RET { };
RET f(T, const T&) { return RET(); } void g(RET) { } void h(const RET&) { }
int main() { //Does this work? { T t1; const T &t2=t1; g(f(t1, t2)); } // -> yes { T t1; T &t2=t1; g(f(t1, t2)); } // -> yes { T t1; T t2; g(f(t1, t2)); } // -> yes { T t1; T t2; h(f(t1, t2)); } // -> yes return 0; }
What it means it that has_operator_plus<LHS, RHS, RET> does not check for exact conformance of arguments LHS and RHS but checks if you can use LHS and RHS as arguments to the operator.
understood. Doesn't this mean, that the naming has_operator_xxx is imprecise and should be operator_xxx_applicable_to or operator_xxx_callable_on instead? Joachim -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de