Using boost::phoenix to adapt a BOOST_CHECK macro

Question

During testing when using c++ 11 I have used the following construct:

std::for_each( coll.begin(), coll.end(), 
    [ &obj, expRes ]( const value_type& val )
    {
       BOOST_CHECK_EQUAL( expRes, obj.someFunc( val ) );
    } );

I am currently working on a project where C++11 is not used and am I a looking for a way to generate a similar lambda expression, without having to create separate a function / functor.

I understand basic use of boost::phoenix to create lambdas, but I cannot think of a way to create a phoenix lambda that is capable of calling a boost::test macro.

The best I can come up with is:

template< typename T >
void MakeCheck( const T& lhs, const T& rhs )
{
    BOOST_CHECK_EQUAL( lhs, rhs );
}


/// inside some other function...
std::for_each( coll.begin(), coll.end(), 
    ph::bind( MakeCheck<bool>, true, 
              ph::bind( &MyClass::someFunc, obj, ph::arg_names::arg1 ) ) );

Unfortunately this approach looses the line number information of failed checks, since the macro BOOST_CHECK_EQUAL reports the line number of the macro, not the line number of the std::for_each call.

Is there a better way of creating a lambda that involves a macro call using 'boost::phoenix`?

Answer 1

Macros are always expanded first, so the only way to get the correct line number would be to:

• not embed macros in templates
• or extract any __LINE__ , __FILE__ , or other context sensitive macros from the template body by turning them into template parameters and wrap the top level expression (macro or template) with a macro using these extracted values.

It's probably not so difficult to refactor the boost code to include these modifications (about 4 levels of nested code), but that wouldn't be easy to maintain afterward.