[C++-sig] Calling python function repr from C++ using boost.python (possible?)

[Jones, Torrin A (US)]

This worked very well thanks.

-----Original Message-----
From: Stefan Ring [mailto:stefanrin at gmail.com] 
Sent: Tuesday, March 05, 2019 12:04 PM
To: Development of Python/C++ integration <cplusplus-sig at python.org>
Cc: Jones, Torrin A (US) <torrin.jones at baesystems.com>
Subject: Re: [C++-sig] Calling python function repr from C++ using boost.python (possible?)

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On Sat, Mar 2, 2019 at 6:12 PM Jones, Torrin A (US) <torrin.jones at baesystems.com> wrote:
>
> Is it possible to call repr from C++ on a C++ object that can be converted to python?  Let me explain.
>
>
>
> I have an enum that I converted to python using boost::python::enum_().  That class already provides a good repr() to python (thanks to the boost::python developers for that).  However that enum is used as a type on a member in another C++ class that I have where boost::python does not provide a good repr().  So I’m trying to provide one and thought, it sure would be nice if I could just call repr() on the member.  I assume I have to convert the value on that member to python first, some kind of way then call repr?  Is that possible?  Or is there a better way?
>
>
>
> Example:
>
>
>
> Typedef enum
>
> {
>
>    V1 = 0,
>
>    V2 = 5,
>
>    V3 = 6
>
> } values;
>
>
>
> Class ValueExample
>
> {
>
>    Public:
>
>       ValueExample(const values& v) {m_value = v};
>
>       Values getValue() const { return m_value };
>
>    Private:
>
>       Values m_value;
>
> }
>
>
>
> Std::string
>
> ValueExampleRepr(const ValueExample& object)
>
> {
>
>    Std::stringstream ss;
>
>
>
>    // What do I put here?
>
>    // Ss << repr(object.getValue());
>
>
>
>    Return ss::str();
>
> }
>
>
>
> Boost::python::enum_<values> values(“values”);
>
> Values.value(“V1”, V1);
>
> Values.value(“V2”, V2);
>
> Values.value(“V3”, V3);
>
>
>
> Boost::python::class_<ValueExample> ValueExample(“ValueExample”);
>
>
>
> ValueExample(“__repr__”, ValueExampleRepr);

I can only come up with this:

Ss << extract<std::string>(boost::python::object(object.getValue()).attr("__repr__")())();