Implement conversion C++ <-> str

[jdemeyer]

In order to clean up the wrapping of C++ code, we need proper conversion of C++ objects to and from Python strings. This is currently done in a hacky way in ccobject.h but it can be done more cleanly using Cython's support for C++ templates.

In particular, we implement:

• ccrepr() to convert any C++ object to str
• ccreadstr() to convert a str to a C++ object

We intentionally use the words repr and read because this is using string input/output (operators << and >>).

Moreover, this new function will support both Python 2 and Python 3. In the latter case, the filesystem encoding is used.

CC: @embray

Component: python3

Author: Jeroen Demeyer

Branch/Commit: b7127ce

Reviewer: Vincent Delecroix

Issue created by migration from https://trac.sagemath.org/ticket/23857

[jdemeyer]

Branch: u/jdemeyer/implement_cppstr___to_convert_any_c___object_to_str

[jdemeyer]

Commit: 5952084

[jdemeyer]

New commits:

5952084

Implement conversion C++ <-> str

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

88d9ded

Implement conversion C++ <-> str

[sagetrac-git]

Changed commit from 5952084 to 88d9ded

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

8598ab6

Implement conversion C++ <-> str

[sagetrac-git]

Changed commit from 88d9ded to 8598ab6

[sagetrac-git]

Changed commit from 8598ab6 to b7127ce

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

b7127ce

Implement conversion C++ <-> str

[videlec]

comment:12

This is nice! How did you test the Python3 version?

[jdemeyer]

comment:13

Replying to @videlec:

This is nice! How did you test the Python3 version?

To be honest, I did not. I am just hoping that it works.

[videlec]

Reviewer: Vincent Delecroix

[vbraun]

Changed branch from u/jdemeyer/implement_cppstr___to_convert_any_c___object_to_str to b7127ce