xo-reflect: + FunctionTdxInfo::make_canonical_name()

include/xo/reflect/TypeDescr.hpp

@@ -148,18 +148,21 @@ namespace xo {
                 return true;
             }
 
+            /** construct canonical description for this type
+             *  will be like
+             *    Retval(*)(Arg1,..,Argn)
+             **/
+            std::string make_canonical_name() const;
+
+        public:
             /** function return value **/
             TypeDescr retval_td_ = nullptr;
             /** function arguments,  in positional order **/
             std::vector<TypeDescr> arg_td_v_;
             /** true iff function promises never to throw **/
             bool is_noexcept_ = false;
-        };
+        }; /*FunctionTdxInfo*/
-    }
-}
 
-namespace xo {
-    namespace reflect {
         class TypeDescrExtra;
 
         /* run-time description for a native c++ type */

src/reflect/TypeDescr.cpp

@@ -15,6 +15,25 @@ namespace xo {
         uint32_t
         TypeId::s_next_id = 1;
 
+        std::string
+        FunctionTdxInfo::make_canonical_name() const
+        {
+            std::ostringstream ss;
+
+            ss << retval_td_->canonical_name();
+            ss << "(*)(";
+            for (std::size_t i = 0, n = arg_td_v_.size(); i < n; ++i) {
+                if (i > 0)
+                    ss << ",";
+                ss << arg_td_v_[i]->canonical_name();
+            }
+            ss << ")";
+
+            return ss.str();
+        } /*make_canonical_name*/
+
+        // ----- TypeDescrBase -----
+
         std::unordered_map<FunctionTdxInfo, TypeDescrBase*>
         TypeDescrBase::s_function_type_map;