-----Original Message----- On Behalf Of Arkadiy Vertleyb "Brian Braatz" <brianb@rmtg.com> wrote

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Is is possible to, given a functor generated as a result of a lambda bind expression, pull the return type from the lambda functor?

I am wondering if "result_of" may be something that you are looking for. OTOH, I don't really know what the status of this library is.

Regards

Thank you for your thoughts- result_of looks like what I want - but I am having difficultly figuring out what the lamda factor LOOKS like after it is compile time generated. (I am (very very) slowly dissecting lambda bind to try to figure this out). IF ANYONE knows the answer to how you would GET TO result_of syntax wise help would be appreciated. (previous mail with sample code below) -----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Brian Braatz Sent: Wednesday, December 22, 2004 8:03 AM To: boost@lists.boost.org Subject: [boost] Help \ Advice requested on getting the return type from aLambda fctor I wrote up the simple example that shows what I am trying to figure out Basically, I am trying to pull the deduced return type (or explicitly passed as a template param in lambda bind()) in my template. If I have a function that is receiving a functor, I would like to be able to take that functor and pull the RETURN TYPE out of it. Lets say I have a function that returns a string: std::string ReturnAString() { return "this is a string"; } And then here is my template function (code below does not compile) template < typename TFUNCTOR> TFUNCTOR::result_type CallFctorDeduceRet( TFUNCTOR & functor) { return functor(); } Now here is my bind call std::cout << ( bind<std::string>(&ReturnAString)); Is there a way to GET to the return type in the Lambda fctor that was generated with a BIND call? I would like to be able to pull the <std::string> from the bind call and use it in the template function. It is not a problem for my template function to be dependant upon lambda bind. I have been going through the lambda code. And while it is brilliant, I am having a bit of difficulty figuring out what I am looking at (grin). Any help or direction is greatly appreciated FULL SAMPLE CODE HERE: template <typename CURRIEDTYPE> // Id class for currying type without creating the object class Id { public: typedef CURRIEDTYPE TYPE; }; // Explictly pass IN a return type template < typename TFUNCTOR, typename TRET> TRET CallFctorPassInRet ( TFUNCTOR & functor, Id<TRET> & ) { Id<TRET>::TYPE TRet; TRet = functor(); return TRet; } std::string ReturnAString() { return "this is a string"; } // try to get return type from the lambda fctor // Below does not compile- but it is along the lines of what I // WANT to do- note that I am trying to get from the Lambda functor the deduced return type template < typename TFUNCTOR> TFUNCTOR::result_type CallFctorDeduceRet( TFUNCTOR & functor) { return functor(); } void Test_LambdaRetDeduction() { std::cout << "CallFctorPassInRet returns [" << CallFctorPassInRet( bind(&ReturnAString), Id<std::string>()) << "]" << std::endl; // below is what I want to make work std::cout << "CallFctorDeduceRet returns [" << CallFctorDeduceRet( bind<std::string>(&ReturnAString)) << "]" << std::endl; }