--- /dev/null
+#pragma once
+
+#include "stg/common.h"
+#include "stg/optional.h"
+
+#include <string>
+#include <map>
+
+namespace SGCONF
+{
+
+template <typename T>
+inline
+void MaybeSet(const std::map<std::string, std::string> & options, const std::string & name, STG::Optional<T> & res)
+{
+std::map<std::string, std::string>::const_iterator it(options.find(name));
+if (it == options.end())
+ return;
+T value;
+if (str2x(it->second, value) < 0)
+ return;
+res = value;
+}
+
+template <typename T, typename F>
+inline
+void MaybeSet(const std::map<std::string, std::string> & options, const std::string & name, T & res, F conv)
+{
+std::map<std::string, std::string>::const_iterator it(options.find(name));
+if (it == options.end())
+ return;
+conv(it->second, res);
+}
+
+template <>
+inline
+void MaybeSet<std::string>(const std::map<std::string, std::string> & options, const std::string & name, STG::Optional<std::string> & res)
+{
+std::map<std::string, std::string>::const_iterator it(options.find(name));
+if (it == options.end())
+ return;
+res = it->second;
+}
+
+} // namespace SGCONF