Update Readme.md of labextension with proper install instructions

[DrBones]

I am delighted to see that we can now use vpython in jupyterlab 3. However, I spend a few hours understanding why the given instruction "jupyter labextension install vpython" did not work and trying to debug a nonexsting issue. It is only when I found a closed issue where @jcoady explained how to install for jlab > 3 that I understood that I was installing the wrong thing.

Maybe the Readme.md can be updated to include the information from that issue that for different jlab versions the following commands need to be executed?

The vpython extension for JuptyerLab 3 and vpython version 7.6.1 can be installed with the command.
pip install jupyterlab-vpython==3.0.4
The vpython extension for JupyterLab 2 and vpython version 7.6.1 can be installed with the command.
jupyter labextension install vpython@2.0.1

Thanks in advance and also for this great visualization package
Cheers

[a3626a]

I think jupyterlab-vpython is a separate project by @jcoady
https://github.com/jcoady/jupyterlab_vpython
and proper installation instruction is there.

Here's another question: Why vpython-jupyter should be diverged into two separate repositories?

[mwcraig]

@DrBones -- you are correct, the installation instructions should be updated.

Took what you wrote and modified it just a touch -- if you have time to open a puol request to add this to the readme that would be great.

---

The vpython extension for JuptyerLab 3 and vpython version 7 can be installed with the command

pip install jupyterlab-vpython

or

conda install -c vpython jupyterlab-vpython

The vpython extension for JupyterLab 2 and vpython version 7 can be installed with the command below after installing nodejs:

jupyter labextension install vpython@2

[mwcraig]

@a3626a

I think jupyterlab-vpython is a separate project by @jcoady
https://github.com/jcoady/jupyterlab_vpython
and proper installation instruction is there.

Sort of... jupyterlab-vpython packages the jupyterlab extension for vpython.

Here's another question: Why vpython-jupyter should be diverged into two separate repositories?

Prior to Jupyter lab 3, vpython had a separate javascript package on npm that was required to allow vpython-jupyter in jupyter lab. That was a hassle because in addition to having a working python installation, you needed a working javascript via nodejs.

jupyter lab 3 allowed extensions to be installed from Python. The recommendation of the jupyter lab developers was to put that into a separate package, though there are projects that put it all into one repository.

One of the factors that led to the current split for vpython is that there are many users who do not use or want jupyter lab. If we roll it all into one package then we need to add jupyterlab as a required dependency.

Your feedback is helpful -- at some point we should perhaps combine them.

[jcoady]

I added jupyterlab-vpython as a submodule in the labextension directory of the vpython-jupyter repository. See the following for a basic explanation of git submodules.

https://gist.github.com/gitaarik/8735255