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]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-In order to clean up the wrapping of C++ code, we need conversion of C++ objects to a string. This is currently done in a hacky way in `ccobject.h` but we propose a much cleaner interface using more modern Cython features.
+In order to clean up the wrapping of C++ code, we need conversion of C++ objects to a string. This is currently done in a hacky way in `ccobject.h` but we propose a much cleaner interface using Cython's support for templates.

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1 +1,3 @@
 In order to clean up the wrapping of C++ code, we need conversion of C++ objects to a string. This is currently done in a hacky way in `ccobject.h` but we propose a much cleaner interface using Cython's support for templates.
+
+Moreover, this new function will support both Python 2 and Python 3. In the latter case, the filesystem encoding is used.

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1,3 +1,3 @@
-In order to clean up the wrapping of C++ code, we need conversion of C++ objects to a string. This is currently done in a hacky way in `ccobject.h` but we propose a much cleaner interface using Cython's support for templates.
+In order to clean up the wrapping of C++ code, we need proper conversion of C++ objects to a Python string. 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.
 
 Moreover, this new function will support both Python 2 and Python 3. In the latter case, the filesystem encoding is used.

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1,3 +1,9 @@
-In order to clean up the wrapping of C++ code, we need proper conversion of C++ objects to a Python string. 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 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.

[jdemeyer]

Branch: u/jdemeyer/implement_cppstr___to_convert_any_c___object_to_str

[jdemeyer]

Commit: 5952084

[jdemeyer]

New commits:

5952084

Implement conversion C++ <-> str