Function operator <<

unittests/catch.hpp:4966–4969

namespace Catch {

    auto operator <<( std::ostream& os, ITransientExpression const& expr ) -> std::ostream& {
        expr.streamReconstructedExpression( os );
        return os;
    }

    LazyExpression::LazyExpression( bool isNegated )
    :   m_isNegated( isNegated )