From herron at ELLINGTON.com  Tue Jul  7 01:04:44 2020
From: herron at ELLINGTON.com (Liam Herron)
Date: Tue, 7 Jul 2020 05:04:44 +0000
Subject: [C++-sig] What is the best way to have a C++ function return a
 python datetime.date object or a python datetime.datetime object?
Message-ID: <96426055F003C542B3FB8A0928736DF904F4FB8103@EX2.ELLINGTON.com>

I have a date and a datetime object in C++ and I would like to add the following methods:
        toPyDate()
        toPyDatetime()
        fromPyDate()
        fromPyDatetime()

I would like to 'bolt-on' these methods to my C++ classes in the BOOST_PYTHON_MODULE interface layer.

I am trying to avoid additional python wrappers around my boost python library.

Can this be done without additional python?   What is the best/cleanest way to do this?

Regards,
Liam Herron

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From Holger.Joukl at LBBW.de  Tue Jul  7 03:29:23 2020
From: Holger.Joukl at LBBW.de (Holger.Joukl at LBBW.de)
Date: Tue, 7 Jul 2020 07:29:23 +0000
Subject: [C++-sig] What is the best way to have a C++ function return a
 python datetime.date object or a python datetime.datetime object?
In-Reply-To: <96426055F003C542B3FB8A0928736DF904F4FB8103@EX2.ELLINGTON.com>
References: <96426055F003C542B3FB8A0928736DF904F4FB8103@EX2.ELLINGTON.com>
Message-ID: <2bd40ed69d2c421cbd969013d74ef05a@LBBW.de>

Hi,

> I have a date and a datetime object in C++ and I would like to add the following methods:
>        toPyDate()
>        toPyDatetime()
>        fromPyDate()
>        fromPyDatetime()
>
> I would like to ?bolt-on? these methods to my C++ classes in the BOOST_PYTHON_MODULE interface layer.
>
> I am trying to avoid additional python wrappers around my boost python library.
>
> Can this be done without additional python?   What is the best/cleanest way to do this?

Without having tried it:

You should probably look at the Python datetime C-API and use it to construct DateTime objects,
then return these from your methods:

https://docs.python.org/3/c-api/datetime.html

Returning PyObjects should allow boost.python to work its magic.

The alternative being auto-magic conversion between your C++ date/time classes and Python
DateTime objects, e.g. along the lines of

https://www.boost.org/doc/libs/1_73_0/libs/python/doc/html/faq/how_can_i_automatically_convert_.html
https://stackoverflow.com/a/16109416

Best regards,
Holger






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