void ParameterExpression::outputCPPImpl(CodeGenerator &cg,
                                        AnalysisResultPtr ar) {
  FunctionScopePtr func =
    dynamic_pointer_cast<FunctionScope>(ar->getScope());
  VariableTablePtr variables = func->getVariables();
  TypePtr paramType = func->getParamType(cg.getItemIndex());
  bool isCVarRef = false;
  if (cg.getContext() == CodeGenerator::CppStaticMethodWrapper ||
      (!variables->isLvalParam(m_name) &&
       !variables->getAttribute(VariableTable::ContainsDynamicVariable) &&
       !variables->getAttribute(VariableTable::ContainsExtract) &&
       !m_ref)) {
    if (paramType->is(Type::KindOfVariant) ||
        paramType->is(Type::KindOfSome)) {
      cg_printf("CVarRef");
      isCVarRef = true;
    }
    else if (paramType->is(Type::KindOfArray)) cg_printf("CArrRef");
    else if (paramType->is(Type::KindOfString)) cg_printf("CStrRef");
    else paramType->outputCPPDecl(cg, ar);
  } else {
    paramType->outputCPPDecl(cg, ar);
  }

  cg_printf(" %s%s", Option::VariablePrefix, m_name.c_str());
  if (m_defaultValue) {
    CodeGenerator::Context context = cg.getContext();
    bool comment =  context == CodeGenerator::CppImplementation ||
      (context == CodeGenerator::CppDeclaration && func->isInlined());
    if (comment) {
      cg_printf(" // ");
    }
    cg_printf(" = ");
    ConstantExpressionPtr con =
      dynamic_pointer_cast<ConstantExpression>(m_defaultValue);
    if (isCVarRef && con && con->isNull()) {
      cg_printf("null_variant");
    } else {
      if (comment) {
        cg.setContext(CodeGenerator::CppParameterDefaultValueImpl);
      } else {
        cg.setContext(CodeGenerator::CppParameterDefaultValueDecl);
      }
      m_defaultValue->outputCPP(cg, ar);
      cg.setContext(context);
    }
    if (comment) {
      cg_printf("\n");
    }
  }
}