Refactor slightly BuiltinFunctionEmbedder and check types

Now the arguments and return values types are checked at construction. One checks if the C++ type corresponds to a pugs type.

Closes #29 (closed)

src/language/modules/BuiltinModule.hpp

@@ -4,10 +4,17 @@
 #include <language/modules/IModule.hpp>
 #include <language/utils/ASTNodeDataType.hpp>
 
+#include <utils/Exceptions.hpp>
+
+#include <sstream>
+
 class IBuiltinFunctionEmbedder;
 class TypeDescriptor;
 class ValueDescriptor;
 
+template <typename FX, typename... Args>
+class BuiltinFunctionEmbedder;
+
 class BuiltinModule : public IModule
 {
  protected:
@@ -15,9 +22,27 @@ class BuiltinModule : public IModule
   NameTypeMap m_name_type_map;
   NameValueMap m_name_value_map;
 
+  template <typename FX, typename... Args>
+  void
+  _addBuiltinFunction(const std::string& name, std::function<FX(Args...)>&& f)
+  {
+    try {
+      this->_addBuiltinFunction(name, std::make_shared<BuiltinFunctionEmbedder<FX(Args...)>>(
+                                        std::forward<std::function<FX(Args...)>>(f)));
+    }
+    catch (std::invalid_argument& e) {
+      std::ostringstream os;
+      os << "while defining builtin function '" << rang::fgB::yellow << name << rang::fg::reset << "'\n";
+      os << e.what();
+      throw UnexpectedError(os.str());
+    }
+  }
+
+ private:
   void _addBuiltinFunction(const std::string& name,
                            std::shared_ptr<IBuiltinFunctionEmbedder> builtin_function_embedder);
 
+ protected:
   void _addTypeDescriptor(const ASTNodeDataType& type);
 
   void _addNameValue(const std::string& name, const ASTNodeDataType& type, const DataVariant& data);