Add signature() to cpp_function_base

src/cpp_function.cpp

@@ -35,6 +35,22 @@ cpp_entity_kind cpp_function_parameter::do_get_entity_kind() const noexcept
     return kind();
 }
 
+std::string cpp_function_base::do_get_signature() const
+{
+    std::string result = "(";
+    for (auto& param : parameters())
+        result += detail::to_string(param.type()) + ',';
+    if (is_variadic())
+        result += "...";
+
+    if (result.back() == ',')
+        result.back() = ')';
+    else
+        result.push_back(')');
+
+    return result;
+}
+
 cpp_entity_kind cpp_function::kind() noexcept
 {
     return cpp_entity_kind::function_t;