C++ Programming :: Template in Template Problem


	Template in Template Problem The following is a much simplified version of some code that is refusing to compile. Is there anything technically wrong with the code? class ClassWithTemplateFunction { public: template<class T> inline void SomeSillyFunction(T value) const { } }; template <typename T> void TemplateFunction( ClassWithTemplateFunction & rC, T value) { rC.SomeSillyFunction< T >( value ); } int main() { ClassWithTemplateFunction C; int value = 0; TemplateFunction<int>(C, value); return 0; } The error I get from the compiler is " Parse error before '>' " on the line: rC.SomeSillyFunction< T >( value ); Any help would be appreciated. - Hide quoted text - easy wrote: > The following is a much simplified version of some code that is > refusing to compile. Is there anything technically wrong with the > code? > class ClassWithTemplateFunction > { > public: > template<class T> inline void SomeSillyFunction(T value) const > { > } > }; > template <typename T> void TemplateFunction( ClassWithTemplateFunction > & rC, T value) > { > rC.SomeSillyFunction< T >( value ); > } > int main() > { > ClassWithTemplateFunction C; > int value = 0; > TemplateFunction<int>(C, value); > return 0; > } > The error I get from the compiler is " Parse error before '>' " on the > line: rC.SomeSillyFunction< T >( value ); > Any help would be appreciated. Try: rC.template SomeSillyFunction< T >( value ); On 16 Feb, 16:19, "easy" <chris.mich@lmco.com> wrote: - Hide quoted text - > The following is a much simplified version of some code that is > refusing to compile. Is there anything technically wrong with the > code? > class ClassWithTemplateFunction > { > public: > template<class T> inline void SomeSillyFunction(T value) const > { > } > }; > template <typename T> void TemplateFunction( ClassWithTemplateFunction > & rC, T value) > { > rC.SomeSillyFunction< T >( value ); > } > int main() > { > ClassWithTemplateFunction C; > int value = 0; > TemplateFunction<int>(C, value); > return 0; > } > The error I get from the compiler is " Parse error before '>' " on the > line: rC.SomeSillyFunction< T >( value ); > Any help would be appreciated. What compiler are you using? Using MS Visual Studio 2005 your code compiles with no errors and when I step through in the debugger it follows the expected path. Also, the code compiles without errors in Comeau online (can't execute it there to see what happens). Gavin Deane On Feb 16, 10:28 am, "Gavin Deane" <deane_ga@hotmail.com> wrote: - Hide quoted text - > On 16 Feb, 16:19, "easy" <chris.mich@lmco.com> wrote: > > The following is a much simplified version of some code that is > > refusing to compile. Is there anything technically wrong with the > > code? > > class ClassWithTemplateFunction > > { > > public: > > template<class T> inline void SomeSillyFunction(T value) const > > { > > } > > }; > > template <typename T> void TemplateFunction( ClassWithTemplateFunction > > & rC, T value) > > { > > rC.SomeSillyFunction< T >( value ); > > } > > int main() > > { > > ClassWithTemplateFunction C; > > int value = 0; > > TemplateFunction<int>(C, value); > > return 0; > > } > > The error I get from the compiler is " Parse error before '>' " on the > > line: rC.SomeSillyFunction< T >( value ); > > Any help would be appreciated. > What compiler are you using? > Using MS Visual Studio 2005 your code compiles with no errors and when > I step through in the debugger it follows the expected path. Also, the > code compiles without errors in Comeau online (can't execute it there > to see what happens). > Gavin Deane- Hide quoted text - > compiler = gcc 3.3.5 On Feb 16, 10:23 am, Rolf Magnus <ramag@t-online.de> wrote: - Hide quoted text - > easy wrote: > > The following is a much simplified version of some code that is > > refusing to compile. Is there anything technically wrong with the > > code? > > class ClassWithTemplateFunction > > { > > public: > > template<class T> inline void SomeSillyFunction(T value) const > > { > > } > > }; > > template <typename T> void TemplateFunction( ClassWithTemplateFunction > > & rC, T value) > > { > > rC.SomeSillyFunction< T >( value ); > > } > > int main() > > { > > ClassWithTemplateFunction C; > > int value = 0; > > TemplateFunction<int>(C, value); > > return 0; > > } > > The error I get from the compiler is " Parse error before '>' " on the > > line: rC.SomeSillyFunction< T >( value ); > > Any help would be appreciated. > Try: > rC.template SomeSillyFunction< T >( value );- Hide quoted text - > I am unfamilliar with inserting the operator "template" in the function call. I will try it. On Feb 16, 10:23 am, Rolf Magnus <ramag@t-online.de> wrote: - Hide quoted text - > easy wrote: > > The following is a much simplified version of some code that is > > refusing to compile. Is there anything technically wrong with the > > code? > > class ClassWithTemplateFunction > > { > > public: > > template<class T> inline void SomeSillyFunction(T value) const > > { > > } > > }; > > template <typename T> void TemplateFunction( ClassWithTemplateFunction > > & rC, T value) > > { > > rC.SomeSillyFunction< T >( value ); > > } > > int main() > > { > > ClassWithTemplateFunction C; > > int value = 0; > > TemplateFunction<int>(C, value); > > return 0; > > } > > The error I get from the compiler is " Parse error before '>' " on the > > line: rC.SomeSillyFunction< T >( value ); > > Any help would be appreciated. > Try: > rC.template SomeSillyFunction< T >( value );- Hide quoted text - > rC.template SomeSillyFunction< T >( value ); compiles. I will have to study more the keyword "template". - Hide quoted text - Rolf Magnus wrote: > easy wrote: >> The following is a much simplified version of some code that is >> refusing to compile. Is there anything technically wrong with the >> code? >> class ClassWithTemplateFunction >> { >> public: >> template<class T> inline void SomeSillyFunction(T value) const >> { >> } >> }; >> template <typename T> void TemplateFunction( ClassWithTemplateFunction >> & rC, T value) >> { >> rC.SomeSillyFunction< T >( value ); >> } >> int main() >> { >> ClassWithTemplateFunction C; >> int value = 0; >> TemplateFunction<int>(C, value); >> return 0; >> } >> The error I get from the compiler is " Parse error before '>' " on the >> line: rC.SomeSillyFunction< T >( value ); >> Any help would be appreciated. > Try: > rC.template SomeSillyFunction< T >( value ); My fix is: rC.SomeSillyFunction( value ); This way the compiler is left to figure out how to instantiate the template. Your fix is rather confusing? Why is adding 'template' here a resolution? Can you make an analogy as an explanation? * Fei Liu: > Rolf Magnus wrote: >> Try: >> rC.template SomeSillyFunction< T >( value ); > My fix is: rC.SomeSillyFunction( value ); > This way the compiler is left to figure out how to instantiate the > template. Your fix is rather confusing? Why is adding 'template' here a > resolution? Can you make an analogy as an explanation? Using the 'template' keyword is a more general fix, because it lets you choose the template parameter(s) independent of the argument's type(s). -- A: Because it messes up the order in which people normally read text. Q: Why is it such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail? Fei Liu wrote: > Rolf Magnus wrote: >> easy wrote: >> Try: >> rC.template SomeSillyFunction< T >( value ); > My fix is: rC.SomeSillyFunction( value ); > This way the compiler is left to figure out how to instantiate the > template. Your fix is rather confusing? Why is adding 'template' here a > resolution? Can you make an analogy as an explanation? I thought template in this context was a FAQ, kind of like typedef typename xxx. Apparently not. On Feb 16, 12:21 pm, Fei Liu <fei@aepnetworks.com> wrote: - Hide quoted text - > Rolf Magnus wrote: > > easy wrote: > >> The following is a much simplified version of some code that is > >> refusing to compile. Is there anything technically wrong with the > >> code? > >> class ClassWithTemplateFunction > >> { > >> public: > >> template<class T> inline void SomeSillyFunction(T value) const > >> { > >> } > >> }; > >> template <typename T> void TemplateFunction( ClassWithTemplateFunction > >> & rC, T value) > >> { > >> rC.SomeSillyFunction< T >( value ); > >> } > >> int main() > >> { > >> ClassWithTemplateFunction C; > >> int value = 0; > >> TemplateFunction<int>(C, value); > >> return 0; > >> } > >> The error I get from the compiler is " Parse error before '>' " on the > >> line: rC.SomeSillyFunction< T >( value ); > >> Any help would be appreciated. > > Try: > > rC.template SomeSillyFunction< T >( value ); > My fix is: rC.SomeSillyFunction( value ); > This way the compiler is left to figure out how to instantiate the > template. Your fix is rather confusing? Why is adding 'template' here a > resolution? Can you make an analogy as an explanation?- Hide quoted text - > Once I knew what to look for I found this discussion. Very helpful. http://groups.google.com/group/comp.lang.c++/browse_thread/thread/248...