Modify the banner for Python3-based Sage

[slelievre]

This ticket is about modifying the banner for Python3-based Sage, if others agree.

For example, if the SageNB notebook does not work in Python3-based Sage, we could replace

Type "notebook()" for the browser-based notebook interface.

by

Powered by Python 3.

[slelievre]

For instance, instead of

┌────────────────────────────────────────────────────────────────────┐
│ SageMath version 8.4.rc0, Release Date: 2018-10-07                 │
│ Type "notebook()" for the browser-based notebook interface.        │
│ Type "help()" for help.                                            │
└────────────────────────────────────────────────────────────────────┘

the banner could look like

┌────────────────────────────────────────────────────────────────────┐
│ SageMath version 8.4.rc0, Release Date: 2018-10-07                 │
│ Powered by Python 3. Type "?" for help.                            │
└────────────────────────────────────────────────────────────────────┘

[chapoton]

notebook() should rather be changed to launch the jupyter notebook

[jhpalmieri]

Is it possible to start the Jupyter notebook from Python? I mean, it must be, but it is not documented in any obvious place.

[slelievre]

From the Sage REPL, providing sage is in the PATH, one can run

sage: os.system('sage -n jupyter')

or just

sage: !sage -n jupyter

In case JupyterLab is also present, one could also do

sage: os.system('sage -n jupyterlab')

or just

sage: !sage -n jupyterlab

Installing JupyterLab can be achieved by running

$ sage --pip install jupyterlab

in a terminal.

[embray]

I would rather simply put the Python version in the banner, if at all. I would just drop the message about notebook() in general; that or change notebook() to launch Jupyter notebook by default.

[chapoton]

here is a proposal

---

New commits:

​578554c

change the banner : no more notebook(), show python version

[chapoton]

My proposal looks like that:

┌────────────────────────────────────────────────────────────────────┐
│ SageMath version 8.5.beta1, Release Date: 2018-10-27               │
│ Using Python 3.6. Type "help()" for help.                          │
└────────────────────────────────────────────────────────────────────┘

[embray]

Fine by me. Maybe bring this up on the mailing list. People tend to have a lot of opinions about this banner, for some reason... (I mean, it is the first thing you see when you start Sage so I guess that makes sense)

[jdemeyer]

+1 to this except that I would mention the complete Python version number (2.7.15 instead of 2.7). It's more informative and I don't see any reason to not use the complete version number.

[klee]

Jupyter seems to prefer narrower banner, as you can see in About ... Kernel menu.

So how about?

│ SageMath 8.5.beta1, released 2018-10-27     |  
│ Using Python 3.6. Type "help()" for help.   │

On the other hand, "Running with" reads better than "Using", though this makes it longer...

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​476633d

trac 26460 banner with full python version

[chapoton]

Now with the full python version. For the width, we are constrained by the beta releases message, so no change. And we do not have any clean command to replace "notebook()"

┌────────────────────────────────────────────────────────────────────┐
│ SageMath version 8.5.beta1, Release Date: 2018-10-27               │
│ Using Python 2.7.15. Type "help()" for help.                       │
└────────────────────────────────────────────────────────────────────┘
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Warning: this is a prerelease version, and it may be unstable.     ┃
┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛

[dimpase]

You've removed the copyright info, which is not so good. How about mimicking the CPython, which has Type "help", "copyright", "credits" or "license" for more information..

So we could have a line saying

Type "help()", "copyright()", or "credits()" for more information.

And Using Python... can be squeezed into the end of the 1st line.

[chapoton]

I have not removed the copyright info. It was commented since long.