Στις 17/6/2017 01:22, ο Jonathan Wakely έγραψε:
On 16 June 2017 at 22:44, Georgios Petasis via gcc-help <gcc-help@xxxxxxxxxxx> wrote:Hi all, I am trying to compile the following code, I am getting an error, and I am unable to fix the error. I am trying to compile this: template<typename Pattern> class HasAttributeMatchingValue: public AnnotationUnaryPredicateWithStates<std::string, Pattern> { bool operator() (const ELEP::CDM::Annotation& ann) const { return ann.containsAttributeMatchingValue(std::get<0>(m_state), std::get<1>(m_state)); }; }; The error I am getting is: `m_state` was not declared in this scope: return ann.containsAttributeMatchingValue(std::get<0>(m_state), std::get<1>(m_state)); If I use instead: template<typename Pattern> class HasAttributeMatchingValue: public AnnotationUnaryPredicateWithStates<std::string, std::string> { bool operator() (const ELEP::CDM::Annotation& ann) const { return ann.containsAttributeMatchingValue(std::get<0>(m_state), std::get<1>(m_state)); }; }; It compiles without problem. AnnotationUnaryPredicateWithStates is a template: template<class... States> class AnnotationUnaryPredicateWithStates : public UnaryPredicateWithStates<ELEP::CDM::Annotation, States ... > {}; template<class Arg, class... States> class UnaryPredicateWithStates : public UnaryFunctionWithStates<Arg, bool, States ... > {}; template<class Arg, class Result, class... Ts> class UnaryFunctionWithStates : public UnaryFunction<Arg, Result> { public: UnaryFunctionWithStates() = default; template <class... Args> UnaryFunctionWithStates(Args&&... args) : m_state(std::forward<Args>(args)...) {}; protected: std::tuple<Ts...> m_state; }; template<class Arg, class Result> class UnaryFunction { public: virtual Result operator()(const Arg &) const = 0; }; What am I doing wrong?See https://gcc.gnu.org/wiki/VerboseDiagnostics#dependent_base
Dear Jonathan, Thank you very much, this solved the problem. I didn't know about it. Regards, George
