Add argument wrapper for directory and files.

tests/python/test_argument_wrapper.cpp

@@ -0,0 +1,69 @@
+#include "pybind11_utils/arg_wrapper.h"
+
+#include <pybind11/pybind11.h>
+#include <pybind11/stl.h>
+
+#include <string>
+
+// wrapper that can be constructed from
+class Wrapper {
+    std::string value;
+
+public:
+    Wrapper() = default;
+
+    Wrapper(Wrapper const&)            = default;
+    Wrapper(Wrapper&&)                 = default;
+    Wrapper& operator=(Wrapper const&) = default;
+    Wrapper& operator=(Wrapper&&)      = default;
+
+    template <class U, std::enable_if_t<std::is_convertible_v<U, std::string>, int> = 0>
+    Wrapper(U&& u) : value{std::forward<U>(u)}
+    {
+    }
+
+    Wrapper(int u) : value{std::to_string(u)} {}
+
+    operator int() const { return std::stoi(value); }
+    operator std::string() const { return value; }
+};
+
+MO2_PYBIND11_WRAP_ARGUMENT_CASTER(Wrapper, int, std::string);
+
+template <std::size_t... Is, class Fn>
+auto wrap(Fn&& fn)
+{
+    return mo2::python::wrap_arguments<Wrapper, Is...>(std::forward<Fn>(fn));
+}
+
+std::string fn1(std::string const& value)
+{
+    return value + "-" + value;
+}
+
+int fn2(int value)
+{
+    return value * 2;
+}
+
+std::string fn3(int value, std::vector<int> values, std::string const& name)
+{
+    return name + "-" + std::to_string(value + values.size());
+}
+
+PYBIND11_MODULE(argument_wrapper, m)
+{
+    m.def("fn1_raw", &fn1);
+    m.def("fn1_wrap", wrap(&fn1));
+    m.def("fn1_wrap_0", wrap<0>(&fn1));
+
+    m.def("fn2_raw", &fn2);
+    m.def("fn2_wrap", wrap(&fn2));
+    m.def("fn2_wrap_0", wrap<0>(&fn2));
+
+    m.def("fn3_raw", &fn3);
+    m.def("fn3_wrap", wrap(&fn3));
+    m.def("fn3_wrap_0", wrap<0>(&fn3));
+    m.def("fn3_wrap_2", wrap<2>(&fn3));
+    m.def("fn3_wrap_0_2", wrap<0, 2>(&fn3));
+}