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POHow to generate a member function with a deduced signature
 

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  1. POHow to generate a member function with a deduced signature
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    <p>is it possible to produce method definition (with an exact number of parameters and return value of known type), having:</p> <ul> <li>method argument types "frozen" in a variadic arguments pack</li> <li>deduced method return type</li> <li>method name (passed to a macro?)</li> </ul> <p>Details:</p> <p>I have a simple reflection structure (partial specialisation stuff omited for readability), which deduces member functions return type and argument types:</p> <pre><code>template&lt;typename RetType, typename ...ArgTypes&gt; struct reflect_method&lt;RetType(HostClassType::*)(ArgTypes...)&gt; { using method_type = RetType; using method_args = type_placeholder&lt;ArgTypes...&gt;; using call_type = RetType(HostClassType::*)(ArgTypes...); }; </code></pre> <p>where <code>method_type</code> is a method return type, <code>method_args</code> are a method argument types "frozen" in a helper template struct <code>type_placeholder</code>.</p> <p>What I'm trying to do is to create a method in a generated class which will reflect arguments and return type of another method of some other class. The created method will provide a decoration for the reflected method.</p> <p>Pseudocode implementation:</p> <pre><code>#define RPCCLASS(class_name) class RPC##class_name : public class_name \ { \ using SelfType = RPC##class_name; \ using ParentType = class_name; #define RPCCLASS_END() }; #define RPCBIND(method_name) \ using method_name_##tag = reflect_method&lt;decltype(ParentType::method_name)&gt;; \ method_name_##tag::method_type method_name(method_name_##tag::method_args::at&lt;0&gt;::type arg0, \ method_name_##tag::method_args::at&lt;1&gt;::type arg1, \ /* ... */ \ /*don't know how to put correct number of arguments here)*/) \ { \ /* do some stuff */ \ /* ... */ \ /* invoke the reflected method */ \ return Invoke&lt;method_name_##tag&gt;::apply(this, method_name, \ arg0, \ arg1 \ /*again don't know how to put correct number of arguments here)*/) \ } // USAGE: class MyOwnClass { public: virtual long long doFun(int a, char b, const std::string&amp; c); }; RPCCLASS(MyOwnClass) RPCBIND(doFun) RPCCLASS_END() </code></pre>
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    1. USTony The Lion
    1. USMarcin
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    1. COYou might want to have a look at the implementation of [Turtle.Mocks](http://turtle.sourceforge.net/) mock object framework. They have something like this in their `MOCK_METHOD` macros
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      1. USArne Mertz
    2. COThank's I'll look into it
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    3. COif you are able to use c++11 shouldn't `decltype` help you alot?
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      1. USAlex
 

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